Acoustic inspection device and method of operation

Abstract

To provide acoustic inspection systems and methods useful for determining microstructural characteristics, such as microtexture regions (MTRs), of a material sample.SOLUTION: In some embodiments, a method of determining a material characteristic of a material sample includes transmitting acoustic waves from a transducer having a concave face that includes one or more piezoelectric elements through a coupling medium to a surface of the material sample to produce surface acoustic waves along a portion of a surface of the material sample. The one or more piezoelectric elements of the concave face may operate as at least one of an acoustic transmitter and an acoustic receiver. The method also includes receiving at the concave face the surface acoustic waves reflected from the surface of the material sample. The method includes then determining at least one material characteristic of the material sample based on a property of the surface acoustic waves.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Application No. 63 / 540737, filed September 27, 2023, and U.S. Provisional Application No. 63 / 470360, filed June 1, 2023, which are incorporated by reference in their entireties.

[0002] These teachings relate generally to systems and methods for inspecting components, and more particularly to acoustic inspection devices and methods of operation thereof. [Background technology]

[0003] Components in various industries may be inspected for properties or characteristics that may affect the properties, performance, or expected life of the component. In the aerospace industry, various components may be formed from metal alloys, such as titanium alloys. However, certain metal alloys may contain microstructures, such as micro-texture regions (MTRs), that may degrade the performance of components formed from the alloy. Therefore, it may be useful to have inspection devices and methods for evaluating the microstructural properties of such materials. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] Venkatesh V, Noraas R, Pilchak A, Tamirisa S, Calvert K, Salem A, et al., Data driven tools and methods for microtexture classification and dwell fatigue life prediction in dual phase titanium alloys, MATEC Web Conf. 2020;321:11091 [Non-patent document 2] Pilchak, AL, Shank, J., Tucker, JC et al., A dataset for the development, verification, and validation of microstructure-sensitive process models for near-alpha titanium alloys, Integr. Mater. Manuf. Innov. 5, 259-276 (2016) Summary of the Invention

[0005] Various needs are met, at least in part, by the provision of acoustic inspection devices and methods of operation as described in the following detailed description, particularly when considered in conjunction with the drawings. A full and enabling disclosure of aspects of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in this specification, which makes reference to the accompanying drawings. [Brief explanation of the drawings]

[0006] [Figure 1] 1 is a schematic diagram of an inspection system according to an embodiment. [Figure 2] Figure 2A is a schematic diagram of an inspection device including a transducer according to an embodiment, Figure 2B is a schematic diagram of the end of the transducer of Figure 2A, and Figure 2C is a schematic diagram of scans performed by the inspection device of Figure 2A at different sound path angles. [Figure 3] Figure 3A is a schematic diagram of an alternative sensing device having a transducer according to an embodiment;Figure 3B is a schematic diagram of the bottom end of the transducer of Figure 3A; [Figure 4] 4A and 4B are a side view and a perspective view, respectively, of an inspection device including a mask according to an embodiment; [Figure 5A] FIG. 1 is a flow diagram of a method for inspecting a material sample according to an embodiment. [Figure 5B] FIG. 1 is a flow diagram of a method for inspecting a material sample according to an embodiment. [Figure 5C] FIG. 1 is a flow diagram of a method for inspecting a material sample according to an embodiment. [Figure 5D] FIG. 1 is a flow diagram of a method for inspecting a material sample according to an embodiment. [Figure 6A] Schematic of an acoustic wave passing through two different crystal structures. [Figure 6B] 6B is a graph of the acoustic signal from the acoustic wave of FIG. 6A. [Figure 7A] FIG. 1 is a schematic diagram of a surface wave scanning a sample. [Figure 7B] FIG. 1 is a schematic diagram of a surface wave scanning a sample. [Figure 8] FIG. 1 is a flow diagram of a method for inspecting a component according to an embodiment. [Figure 9] FIG. 1 is a flow diagram of an inspection method according to an embodiment. [Figure 10] 10A and 10B are exemplary C-scan images of a material sample. [Figure 11] 11A, 11B, and 11C are graphs showing the correlation between acoustic scores and MTR values ​​for several material samples. DETAILED DESCRIPTION OF THE INVENTION

[0007] Elements in the figures are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions and / or relative positions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of various embodiments of the present teachings. Also, common but well-understood elements that are useful or necessary in commercially feasible embodiments are often not depicted to facilitate a more unobtrusive view of these various embodiments of the present teachings. Although certain acts and / or steps may be described or depicted in a particular order of occurrence, those skilled in the art will understand that such specificity with respect to order is not actually required.

[0008] In some cases, determining the microstructural characteristics of a component involves destructive testing, such as electron backscatter diffraction (EBSD). Typically, material samples for EBSD testing are also highly prepared, which may involve, for example, polishing the sample to a mirror finish. Generally speaking, various aspects of the present disclosure present nondestructive techniques for detecting the microstructural characteristics of components formed from materials having a crystalline structure. Nondestructive testing can evaluate the component while avoiding damage to the component during the inspection process. Because nondestructive testing does not damage the component, the component can still be used after inspection and returned to operating condition, reducing costs. Furthermore, the acoustic inspection systems and methods described herein can be performed on simple surfaces that are not highly prepared (e.g., do not need to be polished to a mirror finish) and can evaluate peened and machined surfaces.

[0009] The terms and expressions used herein have the ordinary technical meaning given to such terms and expressions by one of ordinary skill in the art, unless a different specific meaning is otherwise stated herein. The word "or" as used herein shall be construed as having a disjunctive rather than a conjunctive construction, unless otherwise specified. Terms such as "coupled," "fixed," and "attached" refer to both direct coupling, fixing, or attachment, and indirect coupling, fixing, or attachment via one or more intermediate components or features, unless otherwise specified.

[0010] References in the singular include the plural unless the context clearly indicates otherwise.

[0011] The term "approximate" is used throughout this specification and claims to modify any quantitative expression that may vary within acceptable limits without resulting in a change in the relevant basic function. Thus, values ​​modified by terms such as "about," "approximately," and "substantially" should not be limited to the exact value specified. In at least some instances, the term "approximate" may correspond to the precision of an instrument for measuring a value or the precision of a method or machine for constructing or fabricating a component and / or system. For example, the term "approximate" may indicate within a margin of 2.

[0012] Turning now to the figures, FIG. 1 illustrates an inspection system 100 that can be used to inspect a material sample 102. The inspection system 100 can be used to determine one or more properties of the material sample 102. In some embodiments, the material properties may be related to the microstructure of the material sample 102. The material sample 102 may contain discontinuity features, such as cracks, voids, material anomalies (regions of different density or modulus), inclusions, etc., that can be detected by the inspection system 100. The material sample 102 may also have microstructural features that are not cracks, voids, etc., but that can also be detected by the inspection system 100. The microstructural features can be continuous features. Microstructural features (e.g., non-discrete features) can be detected by the system along with discontinuity features. Material properties that can be inferred using the inspection system 100 may include, but are not limited to, grain (crystal) size, grain (crystal) orientation, grain shape, presence of MTRs, size of MTRs, strength of MTRs, orientation of MTRs, macrotexture, dislocation content, residual elastic compressive stress, or tensile stress, etc. In some examples, the material property is MTR characteristics in titanium alloys, grain size in alloys, or textured regions in alloys, such as nickel alloys. The material property can be any MTR property, such as size, shape, strength, density, frequency, orientation, orientation spread, adjacent region properties, or volume fraction. In addition to titanium, the techniques described herein can also be applied to other alloys, including, but not limited to, nickel.

[0013] MTR may refer to a collection of grains with similar crystal orientation. Macrotexture may refer to MTR or grains with a preferred crystal orientation relative to the sample axis. Macrotexture may also cause differences in fatigue strength and tensile strength. It should be noted that changes in material properties can affect the performance of an alloy. For example, increasing the size and / or strength of MTR in titanium alloys decreases room temperature hold fatigue properties. Similarly, increasing macrotexture (measured by the strength of the crystal c-axis orientation in the sample) in titanium alloys increases the 0.2% yield strength and ultimate tensile strength. Increasing grain size decreases fatigue properties in nickel alloys.

[0014] Inspection system 100 includes an inspection device 104, a recorder 110, one or more databases 118 (hereinafter referred to in the singular as database 118), a computing device 124, and a control unit 128. Inspection system 100 and its various components may be operated and controlled via a user interface 144.

[0015] The material sample 102 may be formed from a material having a crystalline structure, such as cubic zirconia, or a metal alloy, such as a titanium alloy, nickel alloy, aluminum alloy, or steel. However, it is contemplated that the devices and methods described herein may be applied to any material in which the characteristics of surface acoustic waves traveling across the material vary as a function of the material's properties and / or in a certain direction within the material's grains (crystals). The material sample 102 may be of any suitable shape, size, or form. The material sample 102 may be a part or component, or in some embodiments, a raw material, such as a billet, plate, forging, or extrusion, used as an input material in another processing operation, such as extrusion, forging, rolling, or machining, to fabricate the part or component. The inspection system 100 may be used to scan any surface of a part or raw material in process. It is also contemplated that a slice or linear sample of a billet, forging, or part may serve as the material sample 102. Thus, the inspection device 104 may be able to detect material properties of raw materials before the raw materials are used to manufacture or otherwise form a component. In this manner, the material properties can be used to establish material quality and determine whether the raw materials are suitable for use in a particular component. Testing before forming a component can ensure that appropriate materials are used to form the component before expending manufacturing efforts and may alleviate the need for testing on manufactured parts or components.

[0016] The forging process of billets and components of metal alloys, such as titanium alloys, can affect the material properties of the metal alloy, such as the size and location of the MTR. For example, the MTR can be formed during billet transformation, in which the titanium alloy is cooled below the beta transus (e.g., the temperature at which the high-temperature beta phase finally begins to transform into the low-temperature alpha phase), and then shaped during billet processing and / or component forging at temperatures below the beta transus. Several factors, such as billet processing, component forging processing, and cooling rate from liquid heat treatment, can affect the formation and shaping of the MTR. Therefore, it is contemplated that the material sample 102 can be taken at any point in the thermomechanical processing of the metal alloy to form a part after material properties such as the MTR have been formed. For example, the material sample 102 can be an end slice of a billet, a microslice of a forged part (e.g., a fan disk), the surface of a forged part, or any other suitable sample taken from a billet, forging, or part before or after any step in the thermomechanical processing of the metal alloy. In some approaches, the material sample 102 may also be a part or component of a gas turbine engine (eg, a part or component before assembly or a part or component disassembled from a gas turbine engine).

[0017] In the illustrated embodiment of FIG. 1 , the inspection device 104 includes a transducer 106 coupled to a mask 107, a scanning device 108, and a coupling medium 109. The transducer 106 includes an acoustic transmitter portion and an acoustic receiver portion. The acoustic transmitter portion can be any suitable device for exciting an area of ​​the material sample 102 with acoustic waves. The acoustic transmitter portion can be any excitation source, energy source, or vibration source that generates or emits acoustic waves or pulses. The acoustic waves can be ultrasonic waves. The acoustic receiver portion can be any suitable device for receiving, measuring, quantifying, or otherwise detecting acoustic waves and / or their properties. The acoustic receiver portion can convert incoming acoustic waves or pulses into an electrical measurement signal (e.g., an acoustic signal) indicative of the incoming acoustic waves. In some configurations, the acoustic receiver portion and the acoustic transmitter portion are contained within and / or implemented by a single piezoelectric device (see, e.g., FIGS. 2A and 2B ). In such a single piezoelectric device, the transducer 106 can be switched between a transmit mode and a receive mode. In other configurations, the acoustic receiver portion and the acoustic transmitter portion are separate piezoelectric devices (see, for example, Figures 3A and 3B).

[0018] In some embodiments, the acoustic transmitter and receiver sections may operate using a single center frequency and associated bandwidth. In other embodiments, the acoustic transmitter and receiver sections may operate by sweeping a range of frequencies. The acoustic transmitter and receiver sections of transducer 106 may operate using frequencies up to about 2 gigahertz, and in some embodiments, may operate using frequencies between about 0.5 MHz and about 100 MHz, or between about 30 MHz and about 50 MHz. It may be desirable to select a frequency having a wavelength in the material that corresponds to the crystal size of the material comprising material sample 102.

[0019] The mask 107 is directly coupled to the transducer 106. The mask 107 can be any structure that blocks acoustic waves. In some embodiments, the mask 107 is shaped to control the sound path angle across the surface of the material sample 102. The mask 107 allows for selection of the direction of acoustic energy, or sound path angle, of the acoustic transmitter portion of the transducer 106. As used herein, the sound path angle refers to the angle across the surface of the material sample 102 relative to a reference line across the surface of the material sample 102. For example, the reference line may correspond to one of the sample coordinate axes or the direction of material flow. The sound path angle is shown in FIG. 2C. Exemplary masks are shown in FIGS. 4A and 4B. It should be understood that the mask 107 is one exemplary configuration for setting the sound path angle. Selecting from among multiple acoustic transmitters and receivers is another exemplary approach for setting the sound path angle (FIGS. 3A and 3B). 3A and 3B, since the sound path angle can be set by selecting pairs of acoustic transmitters and receivers, it is contemplated that the mask 107 may not be included. In some approaches, the mask 107 may be omitted by not including the portion of the piezoelectric active element that is covered by the mask 107.

[0020] The scanning device 108 is configured to adjust the position of the transducer 106 relative to the material sample 102. The scanning device 108 may include a movable platform, a turntable, or another device capable of holding and / or moving the material sample 102. The scanning device 108 may also include a device such as a robotic arm operable to move the transducer 106. The scanning device 108 may be two separate controllable devices operating in conjunction with each other. In some approaches, the scanning device 108 may also be configured to adjust the sound path angle.

[0021] The coupling medium 109 is disposed between the transducer 106 and the material sample 102. The material sample 102, or a portion thereof, may be immersed in or wetted with the coupling medium 109. The coupling medium 109 may fill the propagation gap between the acoustic transmitter and receiver portions of the transducer 106 and the space between the transducer 106 and the surface of the material sample 102. In some approaches, the space surrounding the acoustic transmitter and receiver portions of the transducer and the surface of the material sample 102 may be filled with the coupling medium 109. The coupling medium 109 may be a liquid, such as water, or another fluid couplant, such as an oil or solution. In some embodiments, the coupling medium 109 may be a paste, a gel, or in certain embodiments, a solid. The coupling medium 109 may aid in the transfer of acoustic energy from the transducer 106 to the material sample 102. The coupling medium 109 provides an efficient path for acoustic wave propagation from the transducer 106 to the material sample 102 to improve acoustic wave transmission. For example, acoustic energy may not travel well through air or solids. For example, an impedance mismatch may exist between the transducer 106 and the material sample 102, causing acoustic energy to be reflected back toward the transducer 106 rather than penetrating the material sample 102. The coupling medium 109 may act as a bridge between the transducer 106 and the material sample 102, displacing air and allowing acoustic energy to be transferred to the material sample 102. The coupling medium 109 may help increase or maximize the acoustic energy transferred from the transducer 106 to the material sample 102.

[0022] The recorder 110 is in operative communication with the inspection device 104, particularly with the transducer 106, but may also be in communication with any component of the inspection device 104. The recorder 110 may record any data (e.g., surface acoustic wave data) collected, generated, or otherwise received by the inspection device 104. The recorder 110 may be an acoustic signal recorder for recording the encoded acoustic signal and / or its characteristics on a suitable storage medium. In some approaches, the recorder 110 may record the encoded acoustic signal and / or its characteristics in a database 118. The recorder 110 is configured to acquire signals indicative of the acoustic waves received by the acoustic receiver portion of the transducer 106.

[0023] In some approaches, the recorder 110 can record surface acoustic wave data, which can include characteristics of the acoustic wave. The surface acoustic wave data can include characteristics of the acoustic wave, such as a time of flight 112, a signal amplitude 113, a time series of the signal amplitude 115, a time of arrival 116, and / or a position 117 of the acoustic wave received by the acoustic receiver. The time of flight 112 can include the difference between the time of transmission of the acoustic wave from the transducer 106 and the time of reception of the reflected acoustic wave by the transducer 106. The signal amplitude 113 can represent the strength of the signal representing the acoustic wave received by the transducer 106 and can indicate the strength of the acoustic wave as represented by the wave height. The time series of the signal amplitude 115 can include a series of times at which various signal amplitudes are detected or received by the transducer 106. The time of arrival 116 can indicate the time at which the reflected acoustic wave is received at the transducer 106. The position 117 can indicate the position of the transducer 106 relative to the material sample 102. The surface acoustic wave data may also include geometric features such as size or aspect ratio captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample 102 as characteristics of the acoustic wave data. The signal amplitude time series 115 provides a sequence of arrival events when the acoustic wave is split and multiple arrival times exist (e.g., has multiple propagation times). In some approaches, the recorder 110 may also communicate with the scanning device 108 and record data related to the position and / or sound path angle of the material sample 102 relative to the inspection device 104. In yet another approach, the recorder 110 may also record time data associated with the time when one or more types of data were recorded. For example, the recorder 110 may record time data related to when one or more signals were acquired or received by the inspection device 104 and / or when one or more acoustic waves were transmitted (e.g., the difference between transmission and reception is the propagation time). The recorder 110 may also record position data indicating the location on the material sample 102, such as, for example, the location on the material sample 102 where the acoustic data was acquired and / or the sound path angle. The recorder 110 may also record the entire waveform or a portion thereof received by the inspection device 104 as an A-scan or B-scan.The shape of the waveform may indicate MTR characteristics such as size, intensity, etc.

[0024] Database 118 may include one or more types of data (e.g., surface acoustic wave data) collected or used by inspection system 100. For example, database 118 may include one or more types of data collected, generated, and / or otherwise received by inspection device 104. In another example, database 118 may include data recorded by recorder 110 (such as recorded data 120 in FIG. 1 ). In yet another example, database 118 may include data calculated or otherwise determined by computing device 124 (such as calculated data 122 in FIG. 1 ). As mentioned above, database 118 need not be a single database, but may include one or more databases.

[0025] Computing device 124 is configured to determine at least one property of material sample 102. Computing device 124 may determine the at least one property based, at least in part, on data 120 recorded by recorder 110 and / or on data contained within database 118.

[0026] In some approaches, the computing device 124 may be configured to use the direct values ​​recorded by the recorder 110. For example, the computing device 124 may be configured to use one or more, or a combination of, the following types of data obtained from the inspection device 104: time of flight 112, signal amplitude 113, time series of signal amplitude 115, time of arrival 116, position 117, sound path angle (see FIG. 2B). In one approach, the computing device 124 may determine whether the direct value (or its absolute value) recorded by the recorder 110 meets (e.g., exceeds) a threshold value. In another approach, the computing device 124 may compare data collected at a particular position at different sound path angles.

[0027] Additionally or alternatively, the computing device 124 may be configured to perform statistical correlation or other data analysis of the data 120 recorded by the recorder 110. For example, the computing device 124 may be configured to determine standard deviation, mean, median, spread, variance, Fourier transform, etc. The computing device 124 may determine analysis parameters of time, position statistics, propagation time statistics, and / or signal amplitude statistics, and may include binning data from multiple regions of interest together or applying various filtering techniques such as median or Gaussian filters. In certain embodiments, the computing device 124 may be configured to determine one or more of the following:

[0028] The standard deviation of the propagation times for one or more regions of interest on the material sample 102.

[0029] Averaged propagation times for one or more regions of interest on the material sample 102.

[0030] The maximum value of the propagation time for one or more regions of interest on the material sample 102 .

[0031] The standard deviation of the signal amplitude for one or more regions of interest on the material sample 102.

[0032] The average value of the amplitude for one or more regions of interest on the material sample 102 .

[0033] The maximum amplitude for one or more regions of interest on the material sample 102 .

[0034] The spatial variation of the temporal variation of the propagation time for the material sample 102.

[0035] The spatial variation of the temporal variation of the signal amplitude for the material sample 102.

[0036] Fourier sequence of a time domain signal.

[0037] Fourier sequences for spatial representation of amplitude and / or propagation time signals.

[0038] In some approaches, the computing device 124 may combine data to calculate new measurements, for example, to determine the velocity of acoustic waves propagating across the surface of the material sample 102. Another example may be comparing velocity calculations for different sound path angles at a particular location to estimate the lattice orientation of the grains (crystals). The computing device 124 may further combine calculation results for multiple locations to form an image showing the relative lattice orientation of the grains within the sample. This image may then be further processed to calculate the size, morphology, and / or intensity of microstructural features within the sample, such as MTR. The computing device 124 may determine the velocity based on the propagation time recorded by the recorder 110 and the propagation gap (e.g., the distance the acoustic wave propagates across the surface of the material sample 102).

[0039] In some approaches, the computing device 124 may be calibrated using data from electron backscatter diffraction (EBSD). For example, data 120 recorded by the recorder 110, such as time of flight, may be correlated to material properties, such as microstructural features determined by electron backscatter diffraction (EBSD). In this manner, the computing device 124 may automatically determine or identify material properties based on the characteristics of acoustic waves propagating across the surface of the material.

[0040] The control unit 128 is in operative communication with the inspection device 104, particularly the transducer 106. The control unit 128 may be configured to operate the transducer 106, particularly to operate the acoustic transmitter and receiver portions of the transducer 106 to control the transmission and reception of acoustic waves. In some embodiments, the control unit 128 is configured to control the timing, frequency, and / or sound path angle. In some approaches, the control unit 128 is also configured to control the scanning device 108 to adjust the position of the transducer 106 relative to the material sample 102.

[0041] The control unit 128 typically includes one or more processors 136 and / or microprocessors. The memory 130 stores a set of operational code or instructions 134 that are executed by the control unit 128 and / or the one or more processors 136 to implement the functions of the inspection system 100 and the inspection device 104 or components thereof. In some embodiments, the memory 130 may also store some or all of the data 132 that may be needed to inspect the material sample 102.

[0042] The control unit 128 may be implemented as one or more processors 136. Similarly, the memory 130 may be implemented as one or more memory devices, such as one or more processor-readable and / or computer-readable media, and may include volatile and / or non-volatile media, such as RAM, ROM, EEPROM, flash memory, and / or other memory technologies. Further, while the memory 130 is shown as being internal to the control unit 128, the memory 130 may be internal memory, external memory, or a combination of internal and external memory. Additionally, the control unit 128 typically includes a power supply (not shown), which may be rechargeable and / or may receive power from an external power source.

[0043] The user interface 144 may be used to control one or more components of the inspection system 100. The user interface 144 may be used for user input and / or output display. For example, the user interface 144 may include any known input / output (I / O) devices 138, such as one or more buttons, knobs, selectors, switches, keys, touch input surfaces, audio inputs, and / or displays. Additionally, the user interface 144 may include one or more output display devices, such as, but not limited to, lights, visual indicators, display screens, etc., to communicate communication information, status information, order information, shipping information, notifications, errors, conditions, and / or other such information to the user. Similarly, in some embodiments, the user interface 144 may include an audio system capable of receiving voice commands or requests verbally uttered by the user and / or outputting audio content, alerts, etc.

[0044] In some approaches, the inspection system 100 may further communicate with a manufacturing system 129. The manufacturing system 129 may be any manufacturing system, and in some non-limiting examples, any system that performs thermomechanical processing of components, manufacturing of parts, or manufacturing of raw materials used to form components or parts. In some embodiments, the manufacturing system 129 is used to form the material sample 102 or to form a component, part, or raw material having a similar material composition (e.g., similar alloy composition, crystal structure, etc.) as the material sample 102. The manufacturing system 129 may perform one or more manufacturing processes, for example, to form a component or part or to otherwise perform thermomechanical processing of materials. The inspection system 100 may provide manufacturing process feedback to the manufacturing system 129. For example, the material properties 126 determined by the computing device 124 may be used to adjust parameters of the manufacturing process performed by the manufacturing system 129. For example, if the computing device 124 determines that the material sample 102 has a high MTR strength or an unacceptable microstructure, the inspection system 100 may cause adjustments to the parameters of the manufacturing process performed by the manufacturing system 129 (e.g., the amount of material to be trimmed at the end of the billet).

[0045] In some approaches, the material properties detected by the inspection system 100 may include MTR characteristics of the material sample 102. The MTR characteristics may be characteristics of the MTR within the material sample 102 and / or characteristics of the material sample 102 that are indicative of the presence of the MTR. For example, the material properties may include one or more of the grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of the microtextured regions, intensity of the microtextured regions, orientation of the microtextured regions, macrotexture, dislocation content, residual elastic compressive stress, or tensile stress of the material sample.

[0046] During operation, the inspection device 104 performs at least one scan of the material sample 102. During the scan, the inspection device 104, and in particular the acoustic transmitter portion of the transducer 106, transmits or generates acoustic waves. The acoustic waves propagate through the coupling medium 109 to the surface of the material sample 102 to generate surface acoustic waves that propagate along the surface of the material sample 102 and are received by the receiver portion of the transducer 106. The acoustic receiver portion detects the acoustic waves after they interact with the surface of the material sample 102.

[0047] The control unit 128 may access data acquired by the acoustic receiver portion of the transducer 106, such as data indicative of the surface acoustic waves. Additionally, the control circuitry may determine at least one material property of the material sample based on the data indicative of the surface acoustic waves.

[0048] The acoustic propagation characteristics of the material sample 102 can affect how acoustic waves propagate through or across the material sample 102. The type of material, the method of formation, microstructural features (e.g., MTR), and other factors can affect how acoustic waves propagate. The velocity of acoustic waves can vary as a function of the material properties of the material sample 102, such as the size and strength of MTRs present within the material sample 102. For example, the speed of sound is proportional to the elastic modulus of the material sample. In crystalline materials such as titanium alloys, the elastic modulus is typically affected by the orientation in the material relative to the c-axis or basal pole, which is typically referred to as

[0001] in the Miller-Bravais index. Therefore, the angle of orientation relative to the c-axis of the crystals in the material sample 102, such as a titanium alloy, can also affect the velocity of acoustic waves propagating through the material sample 102. This velocity variation can be measured and used to calculate the absolute orientation of the

[0001] axis of a grain or the average

[0001] orientation of a group of grains relative to the sample surface. In another example, the amplitude of the acoustic waves may vary based on the presence of dislocations or the intensity of MTR regions within the material sample 102. In this manner, the acoustic waves may reveal or otherwise reveal information about the properties of the material sample 102.

[0049] In some approaches, the inspection device 104 may perform scans at multiple different locations on the surface of the material sample 102. In some embodiments, the inspection device 104 may scan the entire surface or a large portion of the surface of the material sample 102. At each location or point on the surface of the material sample, the inspection device 104 may perform scans at multiple different sound path angles, in some embodiments, three or more different sound path angles. That is, the acoustic transmitter portion of the transducer 106 may perform multiple scans at a single point, where the acoustic transmitter portion transmits acoustic waves in multiple directions across the surface of the material sample at a single point. In some approaches, the inspection device 104 performs scans at at least four sound path angles at each location.

[0050] A particular sound propagation direction and / or sound path angle may provide improved resolution or contrast of the propagation time values ​​of the sample. For example, a particular sound propagation direction and / or sound path angle of the acoustic waves may be selected to optimize or otherwise improve the response of the grain structure characteristics of the material sample 102. In some approaches, the sound path angle may be adjusted (e.g., via the position of the slit 198 in FIG. 4B ) to align with the metal flow of the billet if the material sample 102 is a billet, or with the metal flow of the forging if the material sample 102 is a forging. In other approaches, the sound path angle may be adjusted based on one or more properties of the material sample 102.

[0051] The inspection system 100 can detect changes in the crystalline orientation of a sample via changes in surface wave velocity parallel to the propagation direction of the acoustic waves generated by the transducer 106. For a given propagation direction, velocity alone may not be sufficient to provide a unique solution for the orientation of material (e.g., grains) within the region of interest. The maximum velocity in the image may correspond to grains with a

[0001] orientation parallel to the beam propagation direction, while the minimum velocity may correspond to a

[0001] orientation anywhere from the surface normal to 90° relative to the beam propagation direction at the surface. Similarly, intermediate beam velocities may correspond to MTRs oriented in

[0001] at intermediate angles relative to the surface, or may be a mixture of grains at different orientations with an average velocity intermediate between the two extremes. The inspection system 100 can perform additional data processing to extract spatially correlated crystallographic data similar to an EBSD inverse pole figure map.

[0052] For a given location within the material sample 102, a series of acoustic scans can be collected at multiple acoustic wave propagation directions (e.g., sound path angles). The velocity measured at a given point is expected to vary as a function of the inclination of the 0001 with respect to the surface; regions with the 0001 perpendicular to the surface will remain constant for different propagation angles, while regions with the 0001 tilted with respect to the surface will exhibit variable wave propagation velocities. This variation in propagation velocity can be used to determine the inclination of the 0001 with respect to the surface.

[0053] Turning to FIG. 2A, an inspection device 150 is shown that includes a mask 165. FIG. 2A provides a cross-sectional side view of the inspection device 150. The inspection device 150 may correspond to the inspection device 104, and the material sample 160 may correspond to the material sample 102 of FIG. 1. The inspection device 150 includes a transducer 152. The transducer 152 is cylindrical in shape, although in other embodiments, the transducer 152 may have other suitable shapes. The transducer 152 has a concave surface 156. The transducer 152 is mounted adjacent to the surface of the material sample 160. The concave surface 156 of the transducer 152 is located at the end of the transducer 152.

[0054] As shown in FIG. 2A , the concave surface 156 is spaced a distance 166 from the surface of the material sample 160. The concave surface 156 of the transducer 152 can be a hemispherical or non-hemispherical surface bounded by a periphery 159. In one example, the non-hemispherical surface can be a concave rectangular strip having a curved surface. Such a strip may or may not have curved corners. The periphery 159 of the concave surface 156 of the transducer 152 includes an acoustic transmitter portion 157 and an acoustic receiver portion 158. The acoustic transmitter portion 157 and the acoustic receiver portion 158 create a propagation gap between them. The acoustic transmitter portion 157 faces the acoustic receiver portion 158. In this embodiment, the acoustic transmitter portion 157 and the acoustic receiver portion 158 are part of a single piezoelectric device.

[0055] The concave surface 156 is the active element of the transducer 152 and is a single piezoelectric element that operates as both an acoustic transmitter and an acoustic receiver. The concave surface 156 can be switched between a transmit mode and a receive mode during operation. The piezoelectric element can operate in a transmit mode, in which the transducer 152 operates to activate the piezoelectric element (e.g., the concave surface 156) to generate acoustic waves. The piezoelectric element can also operate in a receive (or listening) mode, in which the transducer 152 waits for acoustic waves to reflect off the surface of the material sample 160 and bounce back onto the piezoelectric element (e.g., the concave surface 156). Applying electrical energy to the concave surface 156 causes the concave surface 156 to expand and contract, causing it to vibrate. The vibration of the concave surface 156 results in acoustic waves propagating from the acoustic transmitter portion 157 of the transducer 152 to the material sample 160. The thickness of the active element can determine the frequency of the acoustic waves. The acoustic wave propagates across the surface of the material sample 160. The acoustic wave is reflected from the concave surface 156 and returns to the acoustic receiver portion 158 of the transducer 152.

[0056] Because the concave surface 156 is a piezoelectric material, when acoustic waves reach the concave surface 156, the motion is converted into an electrical signal. If the acoustic waves are ultrasonic, the electrical signal may be referred to as an ultrasonic waveform. The transducer 152 may emit the acoustic waves at a particular pulse repetition rate. The pulses (e.g., transmission of acoustic waves) may be spaced to allow time between pulses so that the acoustic waves have sufficient time to reach the material sample 160 and return to the transducer 152 before the next pulse is generated. It is also contemplated that the acoustic transmitter portion 157 may function as an acoustic receiver and the acoustic receiver portion 158 may function as an acoustic transmitter, such that acoustic waves may also propagate across the material sample 160 in opposite or two directions between the acoustic transmitter portion 157 and the acoustic receiver portion 158.

[0057] The acoustic transmitter portion 157 generates or transmits acoustic waves. As shown, the acoustic waves generated by the acoustic transmitter portion 157 of the transducer 152 impinge on the surface of the material sample 160 at an angle of incidence 164. The angle of incidence 164 is such that the acoustic waves propagate across the propagation gap 162 across the surface of the material sample 160. In some approaches, the angle of incidence is between about 20 degrees and about 40 degrees. In other approaches, the angle of incidence is between about 25 degrees and about 35 degrees. In yet other approaches, the angle of incidence is between about 28 degrees and about 32 degrees, and in some embodiments, the angle of incidence is about 30 degrees. The radius of curvature of the concave surface 156 can be selected to achieve a particular angle of incidence that focuses the acoustic energy and results in surface acoustic waves (Rayleigh waves) propagating across the surface of the material sample 160. The radius of curvature can correspond to the angle of incidence, and therefore, it is contemplated that the aforementioned ranges of angles of incidence also apply to the radius of curvature. For example, the radius of curvature can be between about 20 degrees and about 40 degrees.

[0058] The propagation gap 162 is the distance that the acoustic wave propagates across the surface of the material sample 160. The acoustic wave propagates across the propagation gap 162 and is received by the acoustic receiver portion 158 of the transducer 152. The propagation time of the acoustic wave across the propagation gap 162 is affected by properties such as the microstructure of the material sample 160. For example, the size and orientation of the crystalline grain structure can affect the propagation time of the acoustic wave across the propagation gap 162.

[0059] The inspection device 150 further includes a coupling medium (not shown in FIG. 2A ). In some approaches, the space surrounding the propagation gap 162, the material sample 160, and the concave surface 156 is filled with the coupling medium. In some approaches, the entire inspection device 150 is immersed in the coupling medium (such as the coupling medium 109 of FIG. 1 ). In some approaches, a first volume 161A that immerses the entire concave surface 156 is filled with the coupling medium. In other approaches, a second volume 161B that encompasses the space between the acoustic transmitter portion 157 and the acoustic receiver portion 158, and through which acoustic waves can propagate between the transducer 152 and the surface of the material sample 160, is filled with the coupling medium.

[0060] 2A. The bottom end of the transducer 152 includes a concave surface 156. A peripheral edge 159 of the concave surface 156 is an annular edge to which a mask 165 is coupled. A portion of the peripheral edge 159 of the concave surface 156 is blocked by the mask 165. The mask 165 includes a slit 167 that creates a path from the acoustic transmitter portion 157 to the acoustic receiver portion 158. The slit 167 may help guide or direct acoustic waves from the acoustic transmitter portion 157 to the acoustic receiver portion 158. In some approaches, the mask 165 may be omitted by not including the portion of the piezoelectric active element that is covered by the mask 165.

[0061] FIG. 2C is a top view of a portion of the top surface of the material sample 160 of FIG. 2A. In particular, FIG. 2C illustrates various sound path angles for acoustic waves transmitted and received by the inspection device 150. As illustrated, the inspection device 150 can perform scans at multiple different sound path angles. In the illustrative example shown in FIG. 2C, the inspection device 150 performs four scans, including a scan at a sound path angle of 0 degrees, a scan at a sound path angle of 45 degrees, a scan at a sound path angle of 90 degrees, and a scan at a sound path angle of 135 degrees. The direction between the acoustic transmitter portion 157 and the acoustic receiver portion 158 is used to determine or set the sound path angle. It should be understood that the specific sound path angles illustrated in FIG. 2C are not limiting, and the inspection device 150 can perform scans at any combination of angles and any number of different angles. It is believed that comparing the velocities of surface acoustic waves at different sound path angles can enable estimation of the lattice orientation of particles (crystals).

[0062] 3A shows an inspection device 170 having an alternative configuration. FIG. 3A provides a cross-sectional side view of the inspection device. The inspection device 170 may correspond to the inspection device 104, and the material sample 180 may correspond to the material sample 102 of FIG. 1. The inspection device 170 includes a transducer 172 having a concave surface 174. In this example, the transducer 172 is cylindrical. The transducer 172 is mounted adjacent to the surface of the material sample 180.

[0063] Transducer 172 includes a concave surface 174 that includes an acoustic transmitter portion 176 spaced apart from an acoustic receiver portion 178. In this example, acoustic transmitter portion 176 and acoustic receiver portion 178 are separate piezoelectric elements (whereas FIGS. 2A and 2B include the acoustic transmitter portion and acoustic receiver portion within a single piezoelectric element). Acoustic transmitter portion 176 is positioned opposite acoustic receiver portion 178. Acoustic transmitter portion 176 may include one or more acoustic transmitters. Similarly, acoustic receiver portion 178 may include one or more acoustic receivers.

[0064] The acoustic transmitter portion 176 generates or transmits acoustic waves. As shown, the acoustic waves generated by the acoustic transmitter portion 176 impinge on the surface of the material sample 180 at an angle of incidence 182. The angle of incidence 182 is such that the acoustic waves propagate across a propagation gap 186 across the surface of the material sample 180. In some approaches, the angle of incidence is between about 20 degrees and about 40 degrees, between about 25 degrees and about 35 degrees, between about 28 degrees and about 32 degrees, and in some embodiments, the angle of incidence is about 30 degrees. The radius of curvature of the concave surface 174 can be selected to achieve a particular angle of incidence that results in surface acoustic waves (Rayleigh waves) propagating across the surface of the material sample 180. The acoustic waves are then received by the acoustic receiver portion 178 of the transducer 172.

[0065] The inspection device 170 further includes a sensor 179 to indicate the position of the transducer 172 relative to the material sample 180. The sensor 179 can sense, detect, or otherwise determine the distance 184 between the concave surface 174 and the surface of the material sample 180. The sensor 179 can be a piezoelectric device that functions as an acoustic transmitter and receiver. Thus, the sensor 179 can transmit acoustic waves to the sample and receive reflected waves from the sample. The propagation time of the acoustic waves to the material sample 180 and back to the sensor 179, and the speed of sound through a coupling medium such as water, can then be used to determine the distance 184. In some embodiments, the sensor 179 can also be used to ensure that the material sample 180 is level with the transducer 172. For example, the sensor 179 can be used to measure the distance 184 between the transducer 172 and the material sample 180. The horizontal of material sample 180 may be adjusted until distance 184 is substantially the same at various points across the surface of material sample 180, or otherwise substantially the same at multiple points along material sample 180. To accomplish this, the horizontal of material sample 180 may be adjusted until the propagation times are substantially the same at various points along the surface of the sample. It is contemplated that the surface of material sample 180 may be substantially flat.

[0066] The distance 184 can be used to determine the propagation distance that the acoustic wave propagates between the acoustic transmitter portion 176 and the acoustic receiver portion 178. The propagation distance is represented by the sum of the first distance 177A, the propagation gap 186, and the second distance 177C. The first distance 177A extends between the acoustic transmitter portion 176 and the surface of the material sample 180. The second distance 177C extends between the surface of the material sample 180 and the acoustic receiver portion 178. In some approaches, the propagation distance can be determined via one or more geometric formulas when the distance 184 is known. The propagation gap 186 can also be determined by using one or more geometric formulas when the distance 184 is known. The propagation gap 186, along with the propagation time, is used to determine the velocity of the surface acoustic wave propagating across the surface of the material sample 180.

[0067] The inspection device 170 further includes a coupling medium (not shown in FIG. 3A ). In some approaches, the space surrounding the propagation gap 186, the material sample 180, and the concave surface 174 is filled with the coupling medium. In some approaches, the entire inspection device 170 is immersed in the coupling medium. In some approaches, a first volume 171A that immerses the entire concave surface 174 is filled with the coupling medium. In other approaches, a second volume 171B that encompasses the space between the acoustic transmitter portion 176 and the acoustic receiver portion 178, and through which acoustic waves can propagate between the transducer 172 and the surface of the material sample 180, is filled with the coupling medium.

[0068] Figure 3B is a bottom view of the transducer 172 of Figure 3A. The bottom end of the transducer 172 includes a concave surface 174. The concave surface 174 does not include a mask. Figure 3B shows an acoustic transmitter portion 176, which in this embodiment includes an array of acoustic transmitters, and an acoustic receiver portion 178, which includes an array of acoustic receivers. The acoustic transmitter portion 176 and the acoustic receiver portion 178 are positioned on opposite sides of the concave surface 174. It is also contemplated that the acoustic transmitter portion 176 can function as an acoustic receiver and the acoustic receiver portion 178 can function as an acoustic transmitter, such that acoustic waves can simultaneously propagate in opposite directions across the material sample 180.

[0069] 4A and 4B show a transducer 190 that can be used in the inspection devices described herein. The transducer 190 includes a mounting portion 192 and a recessed surface 194. The recessed surface 194 includes an acoustic transmitter portion and an acoustic receiver portion. The mounting portion 192 can be any suitable structure, mechanism, or device for attaching or coupling the transducer 190 to another structure. The mounting portion 192 can function as a transducer holder. In some examples, the mounting portion 192 is coupled to a portion of an immersion tank used for acoustic inspection. For example, the mounting portion 192 can be coupled to a robotic arm or other structure attached to the immersion tank to move the transducer 190 relative to the material sample to be inspected. Other structures that can be used to move the transducer 190 include, for example, a mast that moves via a drive system. Such a mast can be a linear XY scanner or can have gimbal and / or swivel angle control. The immersion tank can include a coupling medium (coupling medium 109 in FIG. 1). Electrical connections to the transducer 190 may be provided through the interior of the mounting portion 192, although electrical connections may also be supplied from external wiring.

[0070] As shown, the mounting portion 192 includes external threads that are received by complementary threads on another structure. For example, the mounting portion 192 can be coupled to a robotic arm attached to the immersion tank. The transducer 190 can be rotated, for example, to adjust a portion of the mask 196 and, therefore, the sound path angle, by screwing or loosening the threads on the transducer's mounting portion 192 relative to the threads on the other structure. It is also contemplated that the sound path angle can also be adjusted by replacing the mask 196 with a different mask, using a friction-fit rubber cap to attach the mask 196 to the transducer 190, or using the mechanical capabilities of the immersion tank, such as rotating a turntable or mounting portion on which the material sample rests.

[0071] The transducer 190 may include a mask 196. The mask 196 is coupled to the distal end of the transducer 190. In the embodiment shown in FIG. 4B, the mask 196 is coupled to the periphery of the concave surface 194. The mask 196 includes a slit 198 formed therein. The slit 198 is an opening in the mask 196 that provides a path through which acoustic waves can propagate. The mask 196 is configured to direct sound through the slit 198. The mask 196 may be made of any suitable material and may be any suitable size or shape for directing sound from the acoustic transmitter portion (or portion thereof) of the transducer 190 to the acoustic receiver portion (or portion thereof) of the transducer 190. The transducer 190 may be rotated via the mounting portion 192 to adjust the position of the mask 196. Rotating the transducer 190 repositions the slit 198 to adjust the sound path angle.

[0072] The acoustic inspection devices described herein may use other suitable mask configurations. Also, although the transducer 190 uses a mask 196 to adjust the sound path angle, it is contemplated that other suitable manipulation features, devices, or techniques for directing or restricting the propagation of acoustic waves may be used. In some techniques, the mask 196 may be omitted by not including the portion of the piezoelectric active element covered by the mask.

[0073] 5A-5D, a method 200 for inspecting a material sample 202 is shown. In some approaches, the material sample 202 is the material sample 102 described with reference to FIG. 1. The material sample 202 may be in any suitable form or shape, such as a rectangular bar or a circular slice cut from a billet. While the material sample 202 shown in FIGS. 5A-5D is a rectangular bar, in other examples, the material sample 202 may have a different shape. The method 200 may use the inspection system 100 of FIG. 1. Accordingly, the control unit 128, the recorder 110, the inspection device 104, and the computing device 124 may be configured to perform one or more steps of the method 200.

[0074] At block 204, the method 200 includes scanning the material sample 202 at a first sound path angle. The scanning includes transmitting acoustic waves along the surface of the material sample 202 and monitoring properties of the surface acoustic waves. As described above, in some embodiments, the inspection device 104 may scan the material sample 202. In the scanning operation, the transmitter portion of the transducer 106 may transmit acoustic waves, and the receiver portion of the transducer 106 may receive the acoustic waves. The recorder 110 records the properties of the surface acoustic waves. The inspection device 104 may perform multiple scans at the first sound path angle, where the multiple scans occur at multiple different positions or points across the surface of the material sample 202. In some approaches, the scanning device 108 may adjust the position of the material sample 202 and / or the transducer 106 to perform scans at various positions across the surface of the material sample 202.

[0075] Image 204A is an exemplary 2D image of data recorded by recorder 110 after inspection device 104 scans material sample 202. In particular, image 204A shows the propagation times from scans performed at various locations across the surface of material sample 202. The rectangular shape of image 204A corresponds to one of the rectangular surfaces of material sample 202.

[0076] At block 206, the method 200 includes performing additional scans at additional sound path angles via the inspection device 104. In some approaches, the transducer 106 is rotated to perform scans at the additional sound path angles.

[0077] First image 206A, second image 206B, third image 206C, and fourth image 206D are exemplary 2D images of data recorded by recorder 110 from additional scans of a material sample. First image 206A includes data from a scan performed at a first sound path angle (e.g., a sound path angle of 0°). Second image 206B includes data from a scan performed at a second sound path angle (e.g., a sound path angle of 45°). Third image 206C includes data from a scan performed at a third sound path angle (e.g., a sound path angle of 90°). Fourth image 206D includes data from a scan performed at a fourth sound path angle (e.g., a sound path angle of 135°).

[0078] One or more of the steps from block 208 to block 212 may be performed by a control unit, such as control unit 128 described with reference to FIG.

[0079] At block 208, method 200 includes aligning data from different scans to compare data acquired at different sound path angles at a particular location of interest. For example, at location 208A on material sample 202, data from a scan at a first sound path angle (e.g., from first image 206A) is aligned with data from a scan at a second sound path angle (e.g., from second image 206B), data from a scan at a third sound path angle (e.g., from third image 206C), and data from a scan at a fourth sound path angle (e.g., from fourth image 206D).

[0080] In block 210, method 200 includes fitting the aligned data to a sinusoidal function, where the phase shift of the sinusoidal wave is proportional to the angle of the crystal's c-axis. For example, graph 210A provides the flight time for a scan performed at position 208A at each sound path angle. In particular, graph 210A plots flight time as a function of sound wave angle. Graph 210A also shows the flight time data fitted to a sinusoidal function of the form A0 + A × sin(2 × (θ - φ)), where A0 = mean flight time (ToT), A = amplitude of ToT, θ = sound propagation direction angle, and φ = phase shift. This fitting procedure can be ordinary least squares or any other technique capable of determining the best fit of a sinusoidal function to the data.

[0081] At block 212, method 200 includes mapping the data from block 210 onto the surface of material sample 202 to create or generate mapping 212A. For example, if the sinusoidal function has a small phase shift value, the location is marked with a first color, shade, or other indicator in the mapping. If the sinusoidal function for the data at a second location has a larger phase shift value, the second location is marked with a second color, shade, or other indicator in the mapping. It is contemplated that the mapping may include more than two colors, shades, or indicators.

[0082] Mapping 212A is an example of a mapping created by mapping data from block 210 to locations on the surface of material sample 202. Large areas of light or dark shading may indicate MTRs within material sample 202. Large areas of constant color or intensity may indicate areas where the formation of material structures are aligned in the same direction.

[0083] 6A and 6B show acoustic waves passing through two different crystalline structures 218, 220 from a transmitter to a receiver, illustrating how crystal orientation affects the propagation time of acoustic waves propagating through a material. As shown in FIG. 6A, acoustic wave 224 travels faster across the surface of second crystalline structure 220 than acoustic wave 226 travels across the surface of first crystalline structure 218. The difference in speed between acoustic wave 224 and acoustic wave 226 is due, at least in part, to the different grain (crystal) orientations in first crystalline structure 218 and second crystalline structure 220. As a result, acoustic wave 224 propagates farther than acoustic wave 226 over a given amount of time. The circled number 1 indicates the distance acoustic wave 224 propagates across second crystalline structure 220 over a given amount of time. The circled number 2 indicates the distance acoustic wave 226 propagates across first crystalline structure 218 over the same given amount of time.

[0084] Graph 222 in Figure 6B provides a graph of the arrival times of acoustic waves received by the receiver. The arrival time of the acoustic wave passing through the second crystalline structure 220 (which has a faster acoustic velocity) precedes the arrival time of the acoustic wave passing through the first crystalline structure 218. The circled number 1 on graph 222 indicates the arrival time of acoustic wave 224 that propagated across the second crystalline structure 220. The circled number 2 on graph 222 indicates the arrival time of acoustic wave 226 that propagated across the first crystalline structure 218. Acoustic wave 224 propagates at a faster velocity than acoustic wave 226, and therefore arrives at the receiver earlier than acoustic wave 226.

[0085] 7A and 7B are schematic diagrams illustrating a surface acoustic wave scanning over a sample containing a series of MTRs. Diagram 250 in FIG. 7A shows an acoustic wave 254 traveling from an acoustic transmitter to an acoustic receiver through a series of MTRs 256. The axis of each MTR 256 is oriented at a different angle (see angle indicated by reference numeral 258) relative to the direction of the acoustic wave. Surface wave diagram 252 in FIG. 7B illustrates the relative speed at which the acoustic wave propagates through the MTRs 256. The MTRs in surface wave diagram 252 are shaded from dark to light. The darkest shading 260 indicates the shortest propagation time for the acoustic wave to travel from the acoustic transmitter to the acoustic receiver, and therefore indicates the acoustic wave with the fastest velocity. The shortest propagation time may be due to the MTR major axis being parallel to the acoustic wave direction. The lightest shading 262 indicates the longest propagation time for the acoustic wave to travel from the acoustic transmitter to the acoustic receiver, and therefore indicates the acoustic wave with the slowest velocity. The longest propagation time may be due to the MTR's principal axis being perpendicular to the direction of the acoustic wave. As shown, when the axis of the MTR is aligned with the direction of acoustic wave propagation (e.g., when the axis of the MTR is at a 0 degree angle to the direction of the acoustic wave), the propagation time is shortest. The systems and methods described herein exploit the effect of the MTR on acoustic waves propagating therethrough to detect the presence of the MTR in a material sample.

[0086] 8 is a flowchart of a method for inspecting a component according to the techniques described herein. In some techniques, the method may be performed using the inspection system 100 of FIG. 1, the inspection device 150 of FIG. 2A, and / or the inspection device 170 of FIG. 3A.

[0087] In block 280, the method includes causing the acoustic transmitter portion of the transducer to transmit acoustic waves through the coupling medium to the surface of the material sample. The acoustic transmitter portion of the transducer may be positioned adjacent to an edge of the concave surface of the transducer. In some approaches, the transducer may be the transducer 106 described with reference to FIG. 1. For example, the control unit 128 causes the transducer 106 to transmit acoustic waves through the coupling medium 109 to the material sample 102. In some examples, the acoustic transmitter portion 157 of the transducer 152 of FIGS. 2A and 2B may transmit acoustic waves to the material sample 102. Thus, a transducer used to perform the method of FIG. 8 may include the acoustic transmitter portion 157 and the acoustic receiver portion 158 within a single piezoelectric device. In yet another example, the acoustic transmitter portion 176 of the transducer 172 of FIGS. 3A and 3B may transmit acoustic waves to the material sample 102. Thus, the transducer used to perform the method of FIG. 8 may also include acoustic transmitter portion 176 and acoustic receiver portion 178 as separate piezoelectric devices.

[0088] In block 282, the method includes receiving at least one signal indicative of surface acoustic waves. An acoustic receiver portion of the transducer receives the surface acoustic waves and generates a signal indicative of the acoustic waves. The acoustic receiver may be disposed along the edge of the concave surface of the transducer. For example, the transducer 106 may receive the acoustic waves and generate a signal that is indirectly or directly received by the control unit 128. In some examples, the acoustic receiver portion 158 of the transducer 152 of FIGS. 2A and 2B may receive the acoustic waves and generate a signal indicative of such waves. In yet another example, the acoustic receiver portion 178 of the transducer 172 of FIGS. 3A and 3B may receive the acoustic waves and generate a signal indicative of such waves.

[0089] At block 284, the method includes determining at least one material property of the material sample based on characteristics of the surface acoustic waves, e.g., based on characteristics of at least one signal indicative of the surface acoustic waves. In some approaches, a computing device, such as computing device 124 described with reference to FIG. 1, may determine the material property based on the signal. For example, computing device 124 may determine the material property based on the signal amplitude or arrival time. In some examples, the surface acoustic wave property may include at least one of a propagation time, signal amplitude, a time series of signal amplitude, arrival time, and / or position of the acoustic signal received by the acoustic receiver portion. In some examples, the surface acoustic wave property may include geometric features, such as size or aspect ratio, captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample.

[0090] At block 286, the method includes determining whether to accept or reject the material sample (pass / fail) based on at least one material characteristic. In some examples, this operation is performed by a computing device, such as computing device 124. Computing device 124 may compare the material characteristic to a threshold value to determine whether to accept or reject the material sample (pass / fail). In one example, computing device 124 may determine whether the material sample exceeds or falls below a threshold value for MTR strength to determine whether to accept or reject the material sample (pass / fail).

[0091] In some approaches, the method may further include causing the manufacturing system to adjust parameters of a manufacturing process based at least in part on at least one material property. The manufacturing process may be a process that formed the material sample or a process that fabricates a part, component, or material having a material composition similar to that of the material sample. In this manner, the method of FIG. 8 may be used to provide feedback on the manufacturing process based on the material properties of the material sample and adjust the manufacturing process (e.g., the amount of material to be trimmed at the end of the billet) to improve or optimize the manufacturing process. In some examples, this operation is performed by the manufacturing system 129. For example, the control unit 128 may cause the manufacturing system 129 to adjust parameters of the manufacturing system 129.

[0092] 9 provides an additional exemplary inspection method. Method 300 uses surface acoustic wave data to evaluate a material sample. In particular, the method utilizes an acoustic score that predicts one or more material properties, such as the MTR characteristic of the material sample, to determine whether to accept or reject the material sample (pass / fail).

[0093] The surface acoustic wave data used in method 300 may be acquired using one or more acoustic inspection systems or devices. The one or more acoustic inspection systems or devices may include, but are not limited to, the acoustic inspection systems or devices described herein. In one example, inspection system 100 may be used to acquire the surface acoustic wave data.

[0094] At block 310, the method 300 includes receiving surface acoustic wave data about the material sample from the acoustic inspection device. In one example, the control unit 128 of FIG. 1 may receive the surface acoustic wave data about the material sample 102 from the inspection device 104. In particular, the computing device 124 of the control unit 128 may receive the surface acoustic wave data. In some approaches, the surface acoustic wave data used in the method of FIG. 9 includes one or more characteristics of an acoustic waveform (e.g., an acoustic signal received by a transducer of the acoustic inspection device). The surface acoustic wave data may include one or more parameters of the acoustic signal from the surface acoustic wave scan shown in FIG. 1, such as the propagation time 112, signal amplitude 113, time series of signal amplitude 115, arrival time 116, and / or position 117 of the acoustic signal received by the acoustic receiver portion.

[0095] In one non-limiting example, surface acoustic wave data is obtained by transmitting acoustic waves from a transducer having a concave surface including one or more piezoelectric elements through a coupling medium to a surface of the material sample to generate surface acoustic waves along a portion of the surface of the material sample. The one or more piezoelectric elements may operate as at least one of an acoustic transmitter or an acoustic receiver. The surface acoustic wave data is further obtained by receiving the surface acoustic waves reflected from the surface of the material sample at the concave surface.

[0096] At block 320, method 300 includes determining an acoustic score based on the surface acoustic wave data. The acoustic score is a value or other parameter that is a predictor of the MTR level of the material sample. The MTR level can be any MTR characteristic, such as MTR size, shape, intensity, density, frequency, orientation, orientation spread, adjacent region characteristics, or volume fraction, or can be a value or other parameter derived from one or more MTR characteristics. In one example, control unit 128 of FIG. 1 can determine the acoustic score based on the surface acoustic wave data. In particular, computing device 124 of control unit 128 can determine the acoustic score. Exemplary methods for calculating or determining an acoustic score for a material sample based on the surface acoustic wave data of the material sample are further described below. The acoustic score can be based on any statistical calculation using the surface acoustic wave data, and method 300 is not limited to the exemplary methods detailed below that use information entropy, such as Shannon or Renyi entropy, or a gray-level co-occurrence matrix (G).

[0097] Described herein are exemplary methods for determining an acoustic score for a material sample based on surface acoustic wave data. The method may be based on any statistical calculation, such as the standard deviation of the propagation times for one or more regions of interest on the material sample, the mean propagation times for one or more regions of interest on the material sample, the maximum propagation times for one or more regions of interest on the material sample, the standard deviation of the signal amplitude for one or more regions of interest on the material sample, the mean amplitude for one or more regions of interest on the material sample, the maximum amplitude for one or more regions of interest on the material sample, the spatial variation of the temporal variation of the propagation times for the material sample, the spatial variation of the temporal variation of the signal amplitude for the material sample, a Fourier sequence of a time-domain signal, or a Fourier sequence of a spatial representation of the amplitude signal and / or the propagation time signal. Such statistical methods, as well as more complex methods for measuring signal variation, may be applicable to determining the acoustic score. A first exemplary method is based on the calculation of Shannon entropy (H). A second exemplary method is based on a gray-level co-occurrence matrix (G). It is contemplated that any suitable method for calculating an acoustic score based on surface acoustic wave data may be used. These methods can be applied to two-dimensional surface acoustic wave data or can be adapted to full waveform surface acoustic wave data.

[0098] Surface acoustic wave data may include one or more characteristics of the acoustic signal received by the transducer of the acoustic inspection device, such as amplitude, flight time, a time series of amplitude, or a spatially correlated arrangement of amplitude or flight time values. The acoustic signal values ​​may be extracted from the ultrasonic waveform into a C-scan data matrix. The acoustic signal values ​​may be recorded at various times during the signal. The C-scan data matrix is ​​a spatially correlated representation of the structure of the material sample, which may be represented as a two-dimensional matrix of data values. In one example, the spatially correlated representation may include time data (e.g., (x, y, time) data). The data values ​​in the C-scan matrix represent information about the material properties of the material sample. The data in the C-scan matrix may be visualized as an image, with each cell in the matrix corresponding to a specific location on the material sample. The grayscale or color values ​​in the image correspond to the magnitude of the measured signal characteristics.

[0099] Before calculating the acoustic score by statistical methods, the surface acoustic wave data (Y) may first be standardized or normalized. Standardizing or normalizing a set of surface acoustic wave data may include centering each point in the set about the mean value, for example, by subtracting the mean value from each point, and scaling each data point by the standard deviation. In one example, the surface acoustic wave data (Y) may be standardized according to the following formula:

[0100]

number

[0101] where Y' is the normalized surface acoustic wave data, μ is the mean value of the surface acoustic wave data, and σ is the standard deviation of the surface acoustic wave data. The position and time series acoustic wave data can be normalized in different ways. In one example, normalization of the time series data can be based on comparison with a reference sample. After normalization, the normalized acoustic wave data (Y') can be further processed to correct outlying data points and apply noise reduction. The normalized acoustic wave data (Y') can also be converted into an image with several discrete data levels. The image can, for example, show the MTR level at various locations on a cross section of a material sample.

[0102] Figure 10A is a C-scan image of normalized surface acoustic wave data (Y') for a material sample with a low MTR level. Figure 10B is a C-scan image of normalized surface acoustic wave data (Y') for a material sample with a high MTR level. Regions with higher MTR levels have larger, better-aligned MTRs, while regions with lower MTR levels have smaller, less-aligned MTRs.

[0103] In a first exemplary method, an acoustic score for a material sample is calculated.

[0104]

number

[0105] is calculated or determined based on a measure of information entropy. One such measure may be calculated from the Shannon entropy (H). The Shannon entropy (H) is calculated from the normalized surface acoustic wave data (Y'). The Shannon entropy (H) may serve as a measure of uncertainty or randomness in the surface acoustic wave data. Other measures of entropy may also be used. One such additional example is the Renyi entropy.

[0106] In one example, an acoustic scoring computer program

[0107]

number

[0108] can be calculated via the Shannon entropy (H), which can be calculated via the following formula:

[0109]

number

[0110] where A is the area of ​​the material sample or subarea of ​​the material sample over which data is collected, and p i is the probability that a point in region A has a value equal to the i-th level in Y'.

[0111]

number

[0112] is calculated from the value of H for each region in the acoustic scan performed by the acoustic inspection device.

[0113] Another example of an entropy measure is the acoustic score

[0114]

number

[0115] can be calculated via the Renyi entropy via the following formula:

[0116]

number

[0117] where α is an arbitrary constant between 0 and ∞. For α=0, α=1, α→∞, H(A,α) can be evaluated by taking the limit. For α=1, the limit converges to the same metric as the Shannon entropy (H).

[0118] MTR values ​​for multiple material samples

[0119]

number

[0120] The acoustic score

[0121]

number

[0122] By correlating with, an inverse model can be constructed, which is represented by the following equation:

[0123]

number

[0124] where:

[0125]

number

[0126] is the MTR value

[0127]

number

[0128] is the predicted estimate of , and f is the MTR value obtained for multiple material samples.

[0129]

number

[0130] Data and Acoustic Scores

[0131]

number

[0132] This is a regression model constructed from the data. MTR value

[0133]

number

[0134] MTR can be a measurement obtained via data collected from an electron backscatter diffraction (EBSD) scan. In one non-limiting example, data from a field of view measuring approximately 10-15 mm by approximately 10-15 mm is collected, and a segmentation algorithm is used to define regions of interest having similar orientations corresponding to the MTR. One or more of the techniques for segmenting MTRs (or determining MTR values) from EBSD data described in "MTR Analysis and Measurement," IEEE Transactions on Materials Science and Engineering, Vol. 1, No. 1, pp. 111-114, 2003, incorporated by reference, and "MTR Analysis and Measurement," IEEE Transactions on Materials Science and Engineering, Vol. 1, No. 1, pp. 111-114, 2003 ...

[0135]

number

[0136] It should be noted that σ can represent any of a variety of parameters depending on the objectives of a given application.

[0137] In a second exemplary method, the acoustic scores for the sample are

[0138]

number

[0139] is calculated or determined based on a gray level co-occurrence matrix (G). The gray level co-occurrence matrix (G) is calculated from the standardized surface acoustic wave data (Y'). The gray level co-occurrence matrix (G) is a measure of the intensity relationship between a point P1 = (x, y, t) and its neighboring point P2 = (x + Δx, y + Δy, t), where t is the time at which the data is sampled. It is contemplated that this technique may be applied to raw surface wave acoustic data, standardized acoustic wave data, or other transformations of acoustic wave data.

[0140] In one example, the gray level co-occurrence matrix (G) is defined by the following equation: i,j ) is a square matrix containing the joint probability that P1 has intensity i and P2 has intensity j,

[0141]

number

[0142] where N is a constant that normalizes the probability, A is a subset that includes some or all of the data in Y', x and y are the coordinates of a point in region A, Δx and Δy are specified distance offsets, and i and j are the intensity levels of the data in Y'.

[0143] Acoustic score

[0144]

number

[0145] This second estimate of the joint probability p i,j can be derived from

[0146]

number

[0147] where W(i,j) is a weighting function based on i and j, an example is W(i,j)=|ij|, h is an adjustment function, an example is

[0148]

number

[0149] These acoustic scores are square root functions of

[0150]

number

[0151] From the value of

[0152]

number

[0153] The procedure for the equation for can be repeated to construct a similar regression model, as represented by the following equation:

[0154]

number

[0155] In one other exemplary method, the acoustic score

[0156]

number

[0157] is a calculation based on the size, shape, or aspect ratio of a feature in a C-scan of amplitude data, time-of-flight data, or a time series of amplitude data, and the statistical calculation f n continues to be any operation involving basic statistics, Shannon or Renyi entropy, or Gray Level Co-occurrence Matrix (GLCM) values.

[0158] 9, at block 330, the method includes deciding whether to accept or reject the material sample (pass / fail) based on the acoustic score, which is calculated by the method and formula described above with reference to FIGS.

[0159]

number

[0160] In one example, the control unit 128 of FIG. 1 may determine whether to accept or reject (pass / fail) the material sample based on the acoustic score. In particular, the computing device 124 of the control unit 128 may determine whether to accept or reject (pass / fail) the material sample based on the acoustic score. The acoustic score may be compared to a threshold score or threshold range to determine whether to accept or reject (pass / fail) the material sample. The threshold score or threshold range may reflect an acceptable acoustic score value. An acoustic score that falls within the threshold range may reflect that the material from which the material sample was obtained is suitable for use or further processing. If the acoustic score for the material sample is outside the threshold range, the material sample may be rejected.

[0161] The acoustic scores for a material sample can predict the MTR value for the material sample. Figures 11A-11C show the acoustic scores for multiple material samples.

[0162]

number

[0163] (also known as Surface Wave Ultrasonic Testing or SWUT score) and MTR value

[0164]

number

[0165] 11A-11C show exemplary scatter plots correlating MTR values ​​(also called scores) with the mean score.

[0166]

number

[0167] was determined from EBSD tests performed on each of several material samples. The acoustic scores shown in Figures 11A-11C

[0168]

number

[0169] was determined for each of a plurality of material samples based on the acoustic wave data (Y) for each material sample using the methods described herein. The scatter plots in Figures 11A-11C verify the reliability of using the acoustic scores determined by the methods described herein to predict MTR values ​​for material samples. In Figure 11A, the acoustic scores

[0170]

number

[0171] was determined using Shannon entropy (H). In Figure 11B, the acoustic score

[0172]

number

[0173] is the first weight function

[0174]

number

[0175] and the adjustment function h(x) = x, and the gray level co-occurrence matrix (G) was used to determine the acoustic score.

[0176]

number

[0177] is the second weight function W(i,j)=1 and h(x)=h(ΣΣx)=ΣΣx 2 and a gray level co-occurrence matrix (G) was determined using the weighting and adjustment functions. Numerous other weighting and adjustment functions may also be used, depending on the characteristics of the material sample and the inspection system.

[0178] Further aspects of the present disclosure are provided by the following sections:

[0179] An inspection system comprising: a transducer having a concave surface including one or more piezoelectric elements operating as acoustic transmitters and acoustic receivers; a coupling medium filling a space between the transducer and a surface of a material sample; and a control unit in communication with the transducer, the control unit including at least one processor and at least one memory device storing instructions that, when executed by the at least one processor, cause the at least one processor to generate acoustic waves from the concave surface, such that the acoustic waves propagate through the coupling medium along a portion of the surface of the material sample and are transmitted again to the concave surface as surface acoustic waves; accessing data indicative of the surface acoustic waves received at the concave surface; and determining at least one material property of the material sample based on the data.

[0180] 10. The inspection system of any preceding paragraph, wherein the at least one material property includes one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample.

[0181] The inspection system of any preceding paragraph, wherein the concave surface is a single piezoelectric element that switches between a transmit mode and a receive mode.

[0182] 10. The inspection system of any preceding claim, wherein the concave surface includes a first plurality of piezoelectric elements operating as acoustic transmitters and a second plurality of piezoelectric elements spaced apart from the first plurality of piezoelectric elements operating as acoustic receivers, and wherein acoustic waves propagate unidirectionally from the first plurality of piezoelectric elements to the second plurality of piezoelectric elements.

[0183] The inspection system of any preceding paragraph, wherein the coupling medium is water or another fluid couplant.

[0184] 10. The inspection system of any preceding paragraph, wherein the transducer operates using a frequency between about 0.5 MHz and about 100 MHz.

[0185] Any preceding inspection system wherein the transducer operates by at least one of using a single center frequency and associated bandwidth, or by sweeping a range of frequencies.

[0186] The inspection system of any preceding paragraph, wherein the concave surface has a radius of curvature between about 20 degrees and about 40 degrees.

[0187] The inspection system of any preceding paragraph, further comprising a mask coupled to the concave surface of the transducer.

[0188] 10. The inspection system of any preceding paragraph, wherein the at least one material characteristic is a characteristic of microtextured regions in a titanium alloy, a characteristic of grain size in an alloy, or a characteristic of textured regions in a nickel alloy.

[0189] The inspection system of any preceding claim, further comprising a sensor indicating the position of the transducer relative to the material sample.

[0190] The inspection system of any preceding paragraph, wherein the instructions, when executed, cause the at least one processor to cause the transducer to generate acoustic waves at a plurality of sound path angles.

[0191] The inspection system of any preceding paragraph, wherein the concave surface is a hemispherical or rectangular curved surface bounded by a periphery, the periphery of the concave surface acting as at least one of an acoustic transmitter or an acoustic receiver.

[0192] 1. An inspection method comprising: transmitting acoustic waves from a transducer having a concave surface including one or more piezoelectric elements through a coupling medium to a surface of a material sample to generate surface acoustic waves along a portion of the surface of the material sample, the one or more piezoelectric elements operating as an acoustic transmitter and an acoustic receiver; receiving the surface acoustic waves reflected from the surface of the material sample at the concave surface; and determining at least one material property of the material sample based on characteristics of the surface acoustic waves, the at least one material property including one or more of grain size, grain orientation, grain shape, presence of microtextured regions, size of the microtextured regions, intensity of the microtextured regions, orientation of the microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress.

[0193] The inspection method of any preceding paragraph, wherein the at least one material property includes one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample.

[0194] The inspection method of any preceding paragraph, wherein transmitting acoustic waves includes transmitting acoustic waves in multiple directions across the surface of the material sample at a single point.

[0195] The inspection method of any preceding paragraph, further comprising determining at least one material property of the material sample through statistical correlation based on characteristics of the surface acoustic wave.

[0196] The inspection method of any preceding paragraph, wherein the surface acoustic wave characteristics include geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across the area of ​​the material sample.

[0197] The inspection method of any preceding paragraph, further comprising selecting at least one of a frequency or a propagation direction of the acoustic wave to optimize the response of the grain structure characteristic of the material sample.

[0198] The inspection method of any preceding paragraph, wherein the characteristics of the surface acoustic wave include at least one of the arrival time, the propagation time, or the amplitude of the surface acoustic wave.

[0199] 10. The inspection method of any preceding paragraph, wherein at least one material property is the grain structure of the material sample.

[0200] The inspection method of any preceding paragraph, further comprising determining pass / fail of the material sample based on at least one material property.

[0201] The inspection method of any preceding paragraph, further comprising the step of causing the manufacturing system to adjust a parameter of the manufacturing process based on the at least one material property.

[0202] 1. An inspection method comprising: causing a transducer having a concave surface including one or more piezoelectric elements operating as an acoustic transmitter and an acoustic receiver to transmit acoustic waves from the concave surface such that the acoustic waves propagate along a portion of a surface of a material sample through a coupling medium and are transmitted back to the concave surface as surface acoustic waves; accessing data indicative of the surface acoustic waves; determining at least one material property of the material sample based on the data; and determining pass / fail of the material sample based on the at least one material property.

[0203] The inspection method of any preceding paragraph, wherein the at least one material property includes one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample.

[0204] The inspection method of any preceding paragraph, further comprising the step of causing the manufacturing system to adjust a parameter of the manufacturing process based at least in part on the one material property.

[0205] 1. An inspection method comprising: receiving surface acoustic wave data regarding a material sample from an acoustic inspection device; determining an acoustic score that predicts a microtextured region (MTR) level of the material sample, the acoustic score being determined based on the surface acoustic wave data; and determining a pass / fail status of the material sample based on the acoustic score.

[0206] The inspection method of any preceding paragraph, wherein the material sample is at least a portion of a billet, forging, or manufactured part.

[0207] The inspection method of any preceding clause, further comprising the step of standardizing the surface acoustic wave data to obtain standardized surface acoustic wave data.

[0208] 10. The testing method of any preceding paragraph, wherein the acoustic score is determined based on a measure of information entropy determined based on standardized surface acoustic wave data.

[0209] The testing method of any preceding paragraph, wherein the acoustic score is determined based on Shannon entropy or Renyi entropy determined based on standardized acoustic wave data.

[0210] The testing method of any preceding paragraph, wherein the acoustic score is determined based on a gray level co-occurrence matrix (G) determined based on standardized acoustic wave data.

[0211] Any preceding inspection method, wherein the surface acoustic wave data is obtained by transmitting acoustic waves from a transducer having a concave surface including one or more piezoelectric elements to the surface of the material sample through a coupling medium to generate surface acoustic waves along a portion of the surface of the material sample, the one or more piezoelectric elements operating as an acoustic transmitter and an acoustic receiver, and receiving the surface acoustic waves transmitted from the surface of the material sample at the concave surface.

[0212] The inspection method of any preceding paragraph, wherein the acoustic wave data includes surface acoustic wave characteristics, the acoustic wave characteristics including geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material.

[0213] Additional aspects of the present disclosure are provided by the following sections: [Section 1] a transducer having a concave surface including one or more piezoelectric elements that act as an acoustic transmitter and an acoustic receiver; a coupling medium filling a space between the transducer and the surface of the material sample; a control unit in communication with the transducer; the control unit includes at least one processor and at least one memory device; The at least one memory device, when executed by the at least one processor, causes the at least one processor to: causing the transducer to generate acoustic waves from the concave surface such that the acoustic waves propagate through the coupling medium along a portion of the surface of the material sample and are transmitted back to the concave surface as surface acoustic waves; accessing data indicative of the surface acoustic waves received at the concave surface; and determining at least one material property of the material sample based on the data. Inspection system. [Section 2] Item 10. The inspection system of item 1, wherein the concave surface is a single piezoelectric element that switches between a transmit mode and a receive mode. [Section 3] Item 3. The inspection system of item 1 or 2, wherein the concave surface includes a first plurality of piezoelectric elements that act as acoustic transmitters and a second plurality of piezoelectric elements that are spaced apart from the first plurality of piezoelectric elements and act as acoustic receivers, and the acoustic waves propagate in a single direction from the first plurality of piezoelectric elements to the second plurality of piezoelectric elements. [Claim 4] Item 4. The inspection system of any one of items 1 to 3, further comprising a mask coupled to the concave surface of the transducer. [Section 5] 5. The inspection system of any one of claims 1 to 4, wherein the at least one material characteristic includes one or more of the grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample. [Section 6] Item 6. The inspection system of any one of items 1 to 5, further comprising a sensor that indicates the position of the transducer relative to the material sample. [Section 7] 7. The inspection system of any one of clauses 1 to 6, wherein the instructions, when executed, cause the at least one processor to cause the transducer to generate acoustic waves at multiple sound path angles. [Section 8] 8. An inspection system according to any one of claims 1 to 7, wherein the concave surface is a hemispherical or rectangular curved surface bounded by a periphery, and the periphery of the concave surface acts as the acoustic transmitter or the acoustic receiver. [Section 9] transmitting acoustic waves from a transducer having a concave surface including one or more piezoelectric elements operating as an acoustic transmitter and an acoustic receiver to a surface of the material sample through a coupling medium to generate surface acoustic waves along a portion of the surface of the material sample; receiving the surface acoustic waves at the concave surface that are reflected from the surface of the material sample; and determining at least one material property of the material sample based on the characteristics of the surface acoustic wave; The inspection method, wherein the at least one material property comprises one or more of grain size, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress. [Section 10] Item 10. The inspection method described in item 9, wherein transmitting the acoustic wave includes transmitting the acoustic wave in multiple directions across the surface of the material sample at a single point. [Section 11] Item 11. The inspection method according to item 9 or 10, further comprising determining at least one material property of the material sample through statistical correlation based on the characteristics of the surface acoustic wave. [Section 12] An inspection method described in any one of items 9 to 11, further comprising a step of selecting at least one of the frequency or propagation direction of the acoustic wave to optimize the response of the grain structure characteristics of the material sample. [Section 13] 13. The inspection method according to any one of items 9 to 12, wherein the characteristics of the surface acoustic wave include at least one of an arrival time, a propagation time, or an amplitude of the surface acoustic wave. [Section 14] 14. The inspection method of claim 9, wherein the surface acoustic wave characteristics include geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample. [Section 15] 15. The inspection method of claim 9, wherein the at least one material property comprises one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample. [Section 16] Item 16. The inspection method of any one of items 9 to 15, further comprising a step of determining whether the material sample passes or fails based on the at least one material characteristic. [Section 17] 17. The method of any one of claims 9 to 16, further comprising causing a manufacturing system to adjust a parameter of a manufacturing process based on the at least one material property. [Section 18] receiving surface acoustic wave data about the material sample from an acoustic inspection device; determining an acoustic score that predicts a microtextured region (MTR) level of the material sample, the acoustic score being determined based on the surface acoustic wave data; determining whether the material sample passes or fails based on the acoustic score. [Section 19] Item 19. The inspection method of item 18, wherein the surface acoustic wave data includes surface acoustic wave characteristics, the surface acoustic wave characteristics including geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample. [Section 20] 20. The inspection method according to item 18 or 19, further comprising a step of standardizing the surface acoustic wave data to obtain standardized surface acoustic wave data, wherein the acoustic score is determined based on a measure of information entropy determined based on the standardized surface acoustic wave data or a gray level co-occurrence matrix (G) determined based on the standardized acoustic wave data. [Explanation of symbols]

[0214] 100 Inspection Systems 102 Material Samples 104 Inspection Devices 106 Transducer 107 Mask 108 Scanning Device 109 Binding medium 110 Recorder 112 Propagation Time 113 Signal Amplitude 115 Signal Amplitude Time Series 116 Arrival Time 117 position 118 databases 120 Recorded Data 122 Calculation Data 124 Computing Devices 126 Material Properties 128 Control Unit 129 Manufacturing Systems 130 memory 132 Data 134 Command 136 processors 138 Input / Output (I / O) Devices 144 User Interface 150 Inspection Devices 152 Transducer 156 Concave 157 Acoustic transmitter section 158 Acoustic receiver section 159 Periphery 160 material samples 161A First Volume 161B Second Volume 162 Propagation Gap 164 Angle of incidence 165 Mask 166 distance 167 Slit 170 Inspection Devices 171A First Volume 171B Second Volume 172 Transducer 174 Concave 176 Acoustic transmitter section 177A First Distance 177B Propagation Gap 177C Second Distance 178 Acoustic receiver section 179 Sensors 180 material samples 182 Angle of incidence 184 distance 186 Propagation Gap 190 Transducer 192 Mounting part 194 Concave 196 Mask 198 Slit 202 Material Samples 204A Image 206A First Image 206B Second Image 206C Third Image 206D Fourth Image 210A graph 212A Mapping 218 First Crystal Structure 220 Second Crystal Structure 222 graphs 224 Acoustic Wave 226 Acoustic Wave 250 Figures 252 Surface wave diagram 254 Acoustic Wave 256 MTR 258 angle 260 Darkest Shade 262 Lightest Shade

Claims

1. a transducer having a concave surface including one or more piezoelectric elements that act as an acoustic transmitter and an acoustic receiver; a coupling medium filling a space between the transducer and the surface of the material sample; a control unit in communication with the transducer; the control unit includes at least one processor and at least one memory device; The at least one memory device, when executed by the at least one processor, causes the at least one processor to: causing the transducer to generate acoustic waves from the concave surface such that the acoustic waves propagate through the coupling medium along a portion of the surface of the material sample and are transmitted back to the concave surface as surface acoustic waves; accessing data indicative of the surface acoustic waves received at the concave surface; determining at least one material property of the material sample based on the data; and the at least one material property comprises one or more microstructures or microtextures inherent in the material sample; The instructions, when executed, cause the at least one processor to generate acoustic waves at a plurality of sound path angles with the transducer; The data includes the velocity of the surface acoustic wave.

2. 10. The inspection system of claim 1, wherein the concave surface is a single piezoelectric element that switches between a transmit mode and a receive mode.

3. 2. The inspection system of claim 1, wherein the concave surface includes a first plurality of piezoelectric elements that act as acoustic transmitters and a second plurality of piezoelectric elements that are spaced apart from the first plurality of piezoelectric elements and act as acoustic receivers, and the acoustic waves propagate in a single direction from the first plurality of piezoelectric elements to the second plurality of piezoelectric elements.

4. The inspection system of claim 1 further comprising a mask coupled to the concave surface of the transducer.

5. 10. The inspection system of claim 1, wherein the at least one material characteristic comprises one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample.

6. The inspection system of claim 1 further comprising a sensor indicating a position of the transducer relative to the material sample.

7. The inspection system of claim 1 , wherein the concave surface is a hemispherical or rectangular curved surface bounded by a periphery, the periphery of the concave surface acting as the acoustic transmitter or the acoustic receiver.

8. transmitting acoustic waves from a transducer having a concave surface including one or more piezoelectric elements operating as an acoustic transmitter and an acoustic receiver to a surface of the material sample through a coupling medium to generate surface acoustic waves along a portion of the surface of the material sample; receiving the surface acoustic waves at the concave surface that are reflected from the surface of the material sample; determining at least one material property of the material sample based on the characteristics of the surface acoustic wave; the at least one material property comprises one or more microstructures or microtextures inherent in the material sample; transmitting the acoustic waves includes transmitting the acoustic waves in multiple directions across the surface of the material sample at a single point; The inspection method, wherein the characteristics of the surface acoustic wave include a velocity of the surface acoustic wave.

9. The inspection method of claim 8 , further comprising determining at least one material property of the material sample through statistical correlation based on characteristics of the surface acoustic wave.

10. The inspection method of claim 8 , further comprising selecting at least one of a frequency or a propagation direction of the acoustic wave to optimize a response of a grain structure characteristic of the material sample.

11. The inspection method of claim 8 , wherein the properties of the surface acoustic wave include at least one of an arrival time, a propagation time, or an amplitude of the surface acoustic wave.

12. The inspection method of claim 8 , wherein the surface acoustic wave characteristics include geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample.

13. 9. The inspection method of claim 8, wherein the at least one material characteristic comprises one or more of grain size, grain structure, grain orientation, grain shape, presence of microtextured regions, size of microtextured regions, intensity of microtextured regions, orientation of microtextured regions, macrotexture, dislocation content, and residual elastic compressive or tensile stress of the material sample.

14. The method of claim 8 , further comprising determining whether the material sample passes or fails based on the at least one material characteristic.

15. The method of claim 8 , further comprising causing a manufacturing system to adjust a parameter of a manufacturing process based on the at least one material property.

16. receiving surface acoustic wave data about the material sample from an acoustic inspection device; determining an acoustic score that predicts a microtextured region (MTR) level of the material sample, the acoustic score being determined based on the surface acoustic wave data; determining whether the material sample passes or fails based on the acoustic score; the microtextured region (MTR) level comprises one or more microstructures or microtextures inherent to the material sample; The inspection method, wherein the surface acoustic wave data includes surface acoustic wave velocities in multiple directions across the surface of the material sample at a single point.

17. 17. The inspection method of claim 16, wherein the surface acoustic wave data includes surface acoustic wave characteristics, the surface acoustic wave characteristics including geometric features captured in a two-dimensional or three-dimensional representation of the surface acoustic wave response across an area of ​​the material sample.

18. 17. The inspection method of claim 16, further comprising standardizing the surface acoustic wave data to obtain standardized surface acoustic wave data, wherein the acoustic score is determined based on a measure of information entropy determined based on the standardized surface acoustic wave data or a gray level co-occurrence matrix (G) determined based on the standardized acoustic wave data.

Images