A self-calibration multi-channel LIBS alloy material corrosion sensitization degree detection system and method

Abstract

The present application belongs to the technical field of nondestructive testing and spectral analysis, and discloses a self-calibration multi-channel LIBS alloy material corrosion sensitization degree detection system and method. The system comprises a laser excitation module, a laser state monitoring module, a multi-channel spectrometric detection module, a high-frequency acquisition module and a signal processing module. The laser state monitoring module is used to obtain self-calibration information representing laser excitation intensity and focal point state, and the multi-channel spectrometric detection module is used to perform parallel acquisition and calibration on plasma multi-band signals, thereby realizing rapid and accurate detection of the corrosion sensitization degree of alloy materials. Through the present application, the technical pain points of the prior art, such as insufficient detection efficiency, detection results easily affected by laser intensity fluctuations and focal point offset, and lack of actual processing state reference benchmark for multi-channel signals, are effectively overcome, and the present application is suitable for corrosion sensitization degree detection application scenarios of various alloy materials such as aluminum-magnesium alloy, nickel-based alloy and stainless steel.

Description

Technical Field

[0001] This invention belongs to the technical field of nondestructive testing and spectral analysis, and more specifically, relates to a self-calibrated multi-channel LIBS alloy material corrosion sensitization detection system and method. Background Technology

[0002] Engineering materials such as aluminum-magnesium alloys, stainless steel, and nickel-based alloys are widely used in aerospace, marine equipment, energy and chemical industries, and transportation due to their excellent mechanical properties, corrosion resistance, and machinability. However, during long-term service, trace element segregation or precipitates (such as in Al-Mg alloys) often occur at the grain boundaries of these materials. The formation of a corrosive phase (CPS) leads to sensitization, resulting in intergranular corrosion or stress corrosion cracking. Therefore, rapid, accurate, and in-situ detection of the corrosion sensitization of alloy materials is of great significance for ensuring the safe operation of equipment.

[0003] Existing technologies for corrosion sensitization detection mainly include chemical corrosion methods, electrochemical testing methods, and metallographic analysis methods. These methods generally suffer from drawbacks such as complex sample preparation processes, long testing cycles, high destructiveness, and difficulty in online application, making them unsuitable for rapid detection of complex service components or large areas. Laser-induced breakdown spectroscopy (LIBS) offers advantages such as non-contact operation, fast response, suitability for in-situ detection, and multi-element analysis, and is therefore frequently introduced for the compositional analysis and state characterization of metallic materials. Common existing LIBS schemes often employ a spectrometer to collect the emitted plasma light, and then analyze it based on the intensity of the complete spectrum or characteristic spectra.

[0004] While LIBS detection methods can obtain rich spectral information, their system structure is relatively complex, the data volume is large, and the processing speed is limited. Therefore, their detection efficiency and real-time performance remain insufficient for large-area scanning, online detection, or rapid sensitization assessment. To improve detection efficiency, a multi-channel spectroscopic structure can be used to acquire characteristic bands corresponding to matrix material elements and precipitated phase elements in parallel. This reduces redundant information from full-spectrum acquisition, improving detection speed and specificity.

[0005] However, the existing solutions described above still have the following drawbacks or shortcomings: On the one hand, using only multi-channel parallel acquisition is still insufficient to eliminate the influence of laser single-pulse energy fluctuations and actual focusing state changes on the detection results; especially during actual processing and testing, laser focus shift will change the coupling state between the laser and the material, thereby affecting the plasma excitation intensity and the signal amplitude of each detection channel; if calibration information that can reflect the actual processing state is lacking, the comparability and repeatability of multi-channel signals between different sampling points are still limited, thus affecting the accuracy and stability of the detection results. On the other hand, only monitoring the laser emitter can usually only characterize the laser output state, and it is difficult to simultaneously reflect the excitation intensity and focusing state of the laser actually acting on the surface of the material under test.

[0006] Accordingly, there is an urgent need in this field to improve and refine LIBS detection schemes based on multi-channel acquisition in order to better meet the corrosion sensitization requirements of various alloy materials. Summary of the Invention

[0007] To address one or more of the above-mentioned deficiencies or needs of existing technologies, this invention provides a self-calibrating multi-channel LIBS alloy corrosion sensitization detection system and method. By redesigning its overall structure and working principle, and making targeted improvements to the specific structural composition and optical path settings of key modules such as the multi-channel spectroscopic detection module, laser state monitoring module, and laser excitation module, this system not only enables parallel acquisition of matrix material signals and precipitated phase signals using the multi-channel spectroscopic structure, but also allows for self-calibration based on laser processing backlight, thereby significantly improving the efficiency, accuracy, and reliability of alloy corrosion sensitization detection. Compared with existing technologies, it effectively overcomes the technical pain points of insufficient detection efficiency, easy influence of laser intensity fluctuations and focus shift on detection results, and lack of actual processing state reference benchmarks for multi-channel signals. It is especially suitable for corrosion sensitization detection applications of aluminum-magnesium alloys, nickel-based alloys, stainless steel or other alloy materials.

[0008] To achieve the above objectives, according to one aspect of the present invention, a self-calibrating multi-channel LIBS alloy material corrosion sensitization detection system is provided. This system includes a laser excitation module, a multi-channel spectroscopic detection module, a laser state monitoring module, a high-frequency acquisition module, and a signal processing module, wherein: The laser excitation module is used to emit a preset pulsed laser and focus it onto the surface of the alloy material under test through an optical path to generate a plasma radiation signal. The laser return signal of the pulsed laser acting on the alloy material under test returns along the original optical path. The laser state monitoring module is used to collect the target signal corresponding to the laser wavelength in the laser backlight signal, and use it to characterize the excitation intensity and focal state of the pulsed laser actually acting on the surface of the alloy material under test, and at the same time as the subsequent self-calibration data. The multi-channel spectrophotometer is used to receive the plasma radiation signal and separate it into multiple detection channels. The multiple detection channels include at least a matrix material channel and a precipitated phase element channel. The matrix material channel is used to collect the characteristic spectral line signals of the matrix material elements, and the precipitated phase element channel is used to collect the characteristic spectral line signals that correspond to each precipitated phase element. The high-frequency acquisition module is connected to the channel beam splitting detection module and the laser status monitoring module respectively, and is used to perform synchronous acquisition and digital processing of the target signal and the channel signals of each detection channel; The signal processing module performs self-calibration on the channel signals of each detection channel based on the target signal to reduce the influence of laser intensity fluctuations and focus shift. After completing the self-calibration, the channel signals are input into the recognition model to obtain the corrosion sensitization detection results.

[0009] As a further preferred embodiment of the present invention, the laser excitation module includes a laser, a beam expander, a first reflecting mirror, a second reflecting mirror, a scanning galvanometer, a beam reducer, and an objective lens. The pulsed laser emitted by the laser is shaped by the beam expander and then reflected by the first and second reflecting mirrors to the dichroic mirror. The dichroic mirror reflects the pulsed laser, causing it to enter the scanning galvanometer and be focused onto the surface of the alloy material to be tested on the platform after passing through the beam reducer and the objective lens, thereby exciting and generating a plasma radiation signal. Meanwhile, the laser return signal returns along the original optical path, that is, it passes through the objective lens, the beam shrinking lens and the scanning galvanometer in sequence and then reaches the dichroic mirror again. At this time, the target signal in the laser return signal corresponding to the laser wavelength is reflected by the dichroic mirror into the laser state monitoring module, while other signals in the laser return signal are transmitted by the dichroic mirror into the multi-channel beam splitting detection module.

[0010] As a further preferred embodiment of the present invention, the laser state monitoring module preferably includes an attenuator, a focusing lens, a pinhole aperture, and a detector arranged sequentially along the optical path. The focusing lens is used to focus the target signal to the position of the pinhole aperture for limitation, and then the detector receives it. When the laser focusing state of the alloy material under test is normal, the laser return signal forms a concentrated spot near the pinhole aperture after passing through the focusing lens, and is simultaneously received by the detector and outputs the corresponding target signal; when the laser focus of the alloy material under test deviates, the spot size and energy distribution of the laser return signal at the pinhole aperture change, thereby causing the target signal output by the detector to change accordingly.

[0011] As a further preferred embodiment of the present invention, the multi-channel beam splitting detection module is composed of a main optical path and multiple beam splitting links, wherein: A notch filter, multiple dichroic mirrors for beam splitting, and a third mirror are sequentially arranged along the main optical path. The plasma radiation signal passes through the notch filter to suppress the scattering interference of residual laser light, and then is split into various beam splitting links under the action of the multiple dichroic mirrors for beam splitting and the third mirror. Narrow-band pass filters, focusing lenses, and photodetectors are sequentially arranged along each beam splitting link. Each narrow-band pass filter has a different center wavelength, thereby forming multiple detection channels corresponding to different wavebands. The beam splitting signals of each detection channel are focused by the focusing lens and then collected by the photodetector.

[0012] As a further preferred embodiment of the present invention, the multi-channel spectrophotometer preferably further includes one or more auxiliary judgment channels, which are used to collect other characteristic spectral signals besides matrix material elements and precipitated phase elements, in order to enhance the auxiliary discrimination capability of corrosion sensitization detection results.

[0013] As a further preferred embodiment of the present invention, the multi-channel spectrophotometer preferably further includes a background reference channel, which is set to a band position that does not contain matrix material elements and precipitated phase elements, and acquires background band signals for the signal processing module to perform timing alignment and / or amplitude normalization.

[0014] As a further preferred embodiment of the present invention, when the precipitated phase contains multiple elements, it is preferable to set the characteristic spectral line channel and / or auxiliary judgment channel corresponding to each precipitated element to achieve joint detection of different precipitated phase elements.

[0015] As a further preferred embodiment of the present invention, the high-frequency acquisition module preferably includes a high-speed analog-to-digital conversion channel that is respectively connected to the channel beam splitting detection module and the laser status monitoring module.

[0016] As a further preferred embodiment of the present invention, the signal processing module is preferably configured to include a recognition model such as a vector machine, an artificial neural network, or a random forest, and is used to input a multi-channel signal that has completed self-calibration, while outputting classification results, grade results, probability results, or quantitative results that reflect the corrosion sensitization of the alloy material.

[0017] As a further preferred embodiment of the present invention, when the alloy material to be tested is an aluminum-magnesium alloy, the matrix material channel is configured to collect aluminum atomic spectral lines near 396 nm, and the precipitated phase element channel is configured to collect magnesium atomic spectral lines near 279 nm; when a background reference channel is set, the background reference channel is configured to collect continuous background radiation in the 290 nm to 300 nm band; when an auxiliary judgment channel is set, the auxiliary judgment channel is configured to collect magnesium atomic spectral lines near 285 nm.

[0018] According to another aspect of the present invention, a corresponding self-calibrated multi-channel LIBS alloy material corrosion sensitization detection method is also provided, the method comprising: A pulsed laser is focused onto the surface of the alloy material under test to excite and generate a plasma radiation signal, and the laser back signal generated by the pulsed laser is returned to the alloy material under test along the original optical path. The laser state monitoring module collects the target signal corresponding to the laser wavelength from the laser return signal, the multi-channel spectrophotometer collects the characteristic spectral line signals of matrix material elements and precipitated phase elements in parallel, and the high-frequency acquisition module simultaneously collects the target signal and the channel signals of each detection channel and performs digital processing. The signal processing module performs self-calibration on the channel signals of each detection channel based on the target signal, and inputs the self-calibrated channel signals of each detection channel into the recognition model to obtain the corrosion sensitization detection results.

[0019] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages: 1. The core technological improvement of this invention lies first in the redesign of the overall structure and working principle of the detection system. Compared with the existing LIBS detection scheme that uses a spectrometer for full-spectrum acquisition, this invention uses a multi-channel spectroscopic detection structure to acquire target wavelengths in parallel, which reduces redundant spectral information, improves detection efficiency, and is more suitable for in-situ detection, online detection, and large-area scanning detection. Closely in conjunction with this, this invention also sets a laser state monitoring module in the laser processing return optical path, which can directly obtain self-calibration information reflecting the actual processing state, thereby reducing the impact of laser intensity fluctuations and focus shift on the detection results and significantly improving the consistency and stability of the detection results. 2. This invention further makes targeted improvements to the specific composition structure and optical path setting of some key components, such as the multi-channel spectroscopic detection module, the laser state monitoring module, and the laser excitation module. More specifically, by setting matrix material channels and precipitated phase element channels, parallel acquisition of matrix material information and precipitated phase information can be achieved. Auxiliary judgment channels can be flexibly expanded according to the test material system to enhance the auxiliary discrimination capability for different characteristic spectral line signals, thereby improving the sensitivity and applicability of the detection. By optionally setting a background reference channel, timing alignment and / or amplitude normalization of the signals in each detection channel can be further performed, which helps to reduce the influence of surface state changes, background fluctuations, and other factors on the detection results, improving the reliability of the detection results. In addition, by setting a spectroscopic detection dichroic mirror, separate transmission of laser backlight self-calibration and plasma multi-band signal acquisition can be achieved under shared optical path conditions, which helps to simplify the system structure and improve system integration. 3. In this invention, the multi-channel signals after self-calibration can be directly input into the recognition model, thereby enabling rapid identification, grading, and quantitative assessment of the corrosion sensitization of alloy materials. The overall detection system of this invention has a compact structure and is easy to operate, reducing the impact of interference factors on the detection results. Its core components are all conventional industrial parts, which are easy to purchase and integrate. The equipment is small in size and flexible in installation. Compared with the existing technology, it effectively overcomes the technical pain points of insufficient detection efficiency, the susceptibility of detection results to laser intensity fluctuations and focus shifts, and the lack of actual processing state reference benchmarks for multi-channel signals. Therefore, it is particularly suitable for corrosion sensitization detection applications of aluminum-magnesium alloys, nickel-based alloys, stainless steel, or other alloy materials. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of the multi-channel LIBS alloy material corrosion sensitization detection system designed according to the present invention; Figure 2 This is a schematic diagram of the structure of a multi-channel spectrophotometer according to a preferred embodiment of the present invention; Figure 3 This is a schematic diagram illustrating the typical characteristic spectral line distribution of the alloy material to be tested obtained in Embodiment 1 of the present invention; Figure 4a and 4b These are, respectively, schematic diagrams of the scanning dot matrix and corrosion sensitization distribution obtained in Embodiment 1 of the present invention, used to demonstrate the invention. In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein: 100-Laser; 101-Beam expander; 102-First reflecting mirror; 103-Second reflecting mirror; 104-Scanning galvanometer; 105-Beam reducer; 106-Objective lens; 107-Placement platform; 108-Dialect mirror; 210-Multi-channel spectrophotometer module; 211-Photodetector assembly; 2111-Narrowband pass filter; 2112-Focusing lens; 2113-Photodetector; 2114-Spectrophotometer dichroic mirror; 2115-Third reflecting mirror; 212-Notch filter; 220-Laser status monitoring module; 221-Attenuator; 222-Focusing lens; 223-Pinhole aperture; 224-Detector; 300-Signal processing module; 400-Alloy material under test. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Furthermore, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0022] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0023] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0024] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0025] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0026] Figure 1 This is a schematic diagram of the overall structure of a self-calibrating multi-channel LIBS alloy material corrosion sensitization detection system designed according to the present invention. The following will refer to... Figure 1 To explain the invention in more detail.

[0027] (I) Overall System Structure like Figure 1 As shown in the figure, the multi-channel LIBS alloy material corrosion sensitization detection system designed in this invention mainly includes a laser excitation module, a multi-channel spectrophotometer, a laser state monitoring module, a high-frequency acquisition module, and a signal processing module. The basic functions and settings of each module will be explained below.

[0028] The laser excitation module is used to emit a preset pulsed laser and focus it onto the surface of the alloy material 400 under test through an optical path to generate a plasma radiation signal. The laser return signal (and the plasma radiation signal) of the pulsed laser acting on the alloy material 400 under test returns along the original optical path. The laser state monitoring module 220 is used to collect the target signal corresponding to the laser wavelength in the laser backlight signal, and use it to characterize the excitation intensity and focal state of the pulsed laser actually acting on the surface of the alloy material 400 under test, and at the same time as subsequent self-calibration data. The multi-channel spectrophotometer 210 is used to receive the plasma radiation signal and separate it into multiple detection channels. These multiple detection channels include a matrix material channel and a precipitated phase element channel. The matrix material channel is used to collect the characteristic spectral line signals of the matrix material elements, and the precipitated phase element channel is used to collect the characteristic spectral line signals that correspond to each precipitated phase element. The high-frequency acquisition module is connected to the channel beam splitting detection module 210 and the laser status monitoring module 220 respectively, and is used to perform synchronous acquisition and digital processing on the target signal and the channel signals of each detection channel; The signal processing module 300 performs self-calibration on the channel signals of each detection channel based on the target signal to reduce the influence of laser intensity fluctuations and focus shifts. After completing the self-calibration, the channel signals are input into the recognition model to obtain the corrosion sensitization detection results.

[0029] (II) Self-calibration principle of laser status monitoring module The following section will focus on a more detailed explanation of the specific structure and self-calibration principle of the laser state monitoring module, one of the key components of this invention.

[0030] like Figure 1 As shown in the figure, the laser state monitoring module 220 preferably includes an attenuator 221, a focusing lens 222, a pinhole aperture 223 and a detector 224 arranged sequentially along the optical path. The focusing lens 222 is used to focus the target signal to the position of the pinhole aperture 223 for limitation, and then the detector 224 receives it. When the laser focusing state of the alloy material 400 under test is normal, the laser return signal forms a concentrated spot near the pinhole aperture 223 after passing through the focusing lens 222, and is simultaneously received by the detector 224 and outputs the corresponding target signal; when the laser focus of the alloy material 400 under test deviates, the spot size and energy distribution of the laser return signal at the pinhole aperture 223 change, thereby causing the target signal output by the detector 224 to change accordingly.

[0031] Therefore, the combination of pinhole aperture 223 and detector 224 can exhibit a sensitive response to changes in the focal state of the reflected light and provide spatial confinement for non-ideal reflected light in a defocused state. Furthermore, the amplitude variation of the signal output by detector 224 can also reflect changes in the actual laser excitation intensity. Signal processing module 300 can construct self-calibration information based on the above signals for excitation intensity compensation and / or focal shift compensation of multi-channel signals.

[0032] It should be further pointed out that the pinhole aperture 223 and the detector 224 can form a spatial filtering effect, making it easier for the backlight near the focal position to pass through the pinhole aperture, while the backlight deviating from the focal position is suppressed, thereby improving the ability to distinguish changes in the focal state.

[0033] (III) Specific structure and working principle of the multi-channel spectrophotometer The following section will focus on providing a more detailed explanation of the specific structure and working principle of the multi-channel spectrophotometer, another key component of this invention.

[0034] Figure 2 This is a schematic diagram of a multi-channel spectrophotometer according to a preferred embodiment of the present invention, as shown below. Figure 2 As shown, the multi-channel beam splitting detection module 210, which constitutes another key component of the present invention, is composed of a main optical path and multiple beam splitting links, wherein: A notch filter 212, multiple dichroic mirrors 2114 and a third mirror 2115 are sequentially arranged along the main optical path. The plasma radiation signal passes through the notch filter 212 to suppress the scattering interference of residual laser light, and then is split into various beam splitting links under the action of the multiple dichroic mirrors 2114 and the third mirror 2115. A narrow-band pass filter 2111, a focusing lens 2112, and a photodetector 2113 are sequentially arranged along each beam splitting link. Each narrow-band pass filter 2111 has a different center wavelength, thereby forming multiple detection channels corresponding to different wavebands. The beam splitting signals of each detection channel are focused and processed by the focusing lens 2112 and then collected by the photodetector 2113.

[0035] It should be further emphasized that the plurality of detection channels includes at least one matrix material channel and one precipitated phase element channel. The matrix material channel is used to acquire the characteristic spectral line signals of the matrix material elements, and the precipitated phase element channel is used to acquire the characteristic spectral line signals of the precipitated phase elements.

[0036] According to a preferred embodiment of the present invention, one or more auxiliary judgment channels may be provided to acquire other characteristic spectral line signals of matrix material elements and / or precipitated phase elements, thereby enhancing the auxiliary discrimination capability of the detection results. In another preferred embodiment, a background reference channel may be provided, which is selected at a band position that does not contain characteristic spectral lines of matrix material elements and precipitated phase elements, for acquiring background band signals. This background band signal can be used by the signal processing module 300 to perform timing alignment and / or amplitude normalization. Furthermore, when the precipitated phase contains multiple elements, characteristic spectral line channels and / or auxiliary judgment channels corresponding to each precipitated phase element may be further provided to achieve joint detection of different precipitated phase elements.

[0037] According to another preferred embodiment of the present invention, when the alloy material to be tested is an aluminum-magnesium alloy, the matrix material channel is configured to collect aluminum atomic spectral lines near 396 nm, and the precipitated phase element channel is configured to collect magnesium atomic spectral lines near 279 nm; when a background reference channel is set, the background reference channel is configured to collect continuous background radiation in the 290 nm to 300 nm band; when an auxiliary judgment channel is set, the auxiliary judgment channel is configured to collect magnesium atomic spectral lines near 285 nm.

[0038] (iv) Specific structure and working principle of the laser excitation module The following section will focus on providing a more detailed explanation of the specific structure and working principle of the laser excitation module, another key component of this invention.

[0039] like Figure 1 As shown, the laser excitation module preferably includes a laser 100, a beam expander 101, a first reflector 102, a second reflector 103, a scanning galvanometer 104, a beam reducer 105, and an objective lens 106. The pulsed laser emitted by the laser 100 is shaped by the beam expander 101 and then reflected by the first reflector 102 and the second reflector 103 to the dichroic mirror 108. The dichroic mirror 108 reflects the pulsed laser, allowing it to enter the scanning galvanometer 104 and be focused onto the surface of the alloy material 400 to be tested on the platform 107 after passing through the beam reducer 105 and the objective lens 106, thereby exciting and generating a plasma radiation signal. Meanwhile, the laser return signal (and the plasma radiation signal generated by the alloy material 400 under test) returns along the original optical path, that is, after passing through the objective lens 106, the beam shrinking mirror 105 and the scanning galvanometer 104 in sequence, it reaches the dichroic mirror 108 again. At this time, the target signal in the laser return signal corresponding to the laser wavelength is reflected by the dichroic mirror 108 into the laser state monitoring module 220, while other signals in the laser return signal are transmitted by the dichroic mirror 108 into the multi-channel spectrophotometer 210.

[0040] (v) Detailed structural description of other functional modules According to another preferred embodiment of the present invention, the signal processing module 300 can be configured to include a recognition model such as a vector machine, an artificial neural network, or a random forest, and is used to input a multi-channel signal that has completed self-calibration, while outputting classification results, grade results, probability results, or quantitative results that reflect the corrosion sensitization of the alloy material.

[0041] In addition, the high-frequency acquisition module preferably includes high-speed analog-to-digital conversion channels respectively configured to correspond to the laser state monitoring module and each photoelectric detection component; the photoelectric detection component preferably adopts an avalanche photodiode and / or a photomultiplier tube.

[0042] The working process of the multi-channel LIBS alloy material corrosion sensitization detection system of the present invention will be described in detail below.

[0043] During the testing process, the laser state monitoring module 220 first collects the laser backlight signal generated by the material under test 400 after being subjected to pulsed laser, and outputs self-calibration information characterizing the laser excitation intensity and / or focal state.

[0044] Subsequently, the laser excitation module focuses the main laser beam onto the surface of the material under test 400, exciting and generating plasma. The multi-channel spectrophotometer 210 splits the plasma radiation signal, and the matrix material channel, the precipitated phase element channel, and the optional auxiliary judgment channel and background reference channel respectively acquire the corresponding band signals, thereby realizing the parallel acquisition of the target band signal.

[0045] The high-frequency acquisition module synchronously acquires and digitizes the laser return signal and signals from each detection channel, and transmits them to the signal processing module 300.

[0046] The signal processing module 300 calibrates the signals of each detection channel based on the self-calibration information to reduce the impact of laser intensity fluctuations and / or focus shifts. When a background reference channel is set, timing alignment and / or amplitude normalization can be further performed.

[0047] After calibration, the signal processing module 300 inputs the multi-channel signal into the recognition model to output corrosion sensitization recognition results, grade results, probability results, or quantitative results.

[0048] To facilitate a better understanding of the present invention, a specific embodiment is provided below.

[0049] Example 1 In this embodiment, the material under test 400 is an aluminum-magnesium alloy. The matrix material channel is configured to collect aluminum atomic spectral lines around 396 nm, and the precipitated phase element channel is configured to collect magnesium atomic spectral lines around 279 nm. The auxiliary judgment channel can be configured to collect magnesium atomic spectral lines around 285 nm. The background reference channel can be configured to collect background radiation signals in the 290 nm to 300 nm band.

[0050] During the detection process, the system acquires self-calibration information characterizing the laser excitation intensity and focal state through the laser state monitoring module 220, and calibrates the acquired signals of the aluminum channel, magnesium channel, optional auxiliary judgment channel, and background reference channel. Subsequently, by combining the calibrated multi-channel signals, the corrosion sensitization of the aluminum-magnesium alloy surface is identified, graded, or quantitatively assessed.

[0051] like Figure 3 The diagram shows a schematic representation of the typical characteristic spectral line distribution of the alloy material to be tested, obtained according to Example 1; furthermore, as shown... Figure 4a As shown, the laser excitation module can drive the main laser beam to scan the area to be measured point by point along a predetermined scanning path, forming a scanning dot matrix; simultaneously, as Figure 4b As shown, the signal processing module 300 can map the calibrated identification results of each scanning point into a two-dimensional corrosion sensitization distribution map. The two-dimensional distribution map can be used to display the spatial distribution of corrosion sensitization within the test area, and can further output the overall corrosion sensitization level of the test area.

[0052] It should be noted that this invention is not limited to aluminum-magnesium alloy systems. For stainless steel, nickel-based alloys, or other alloy materials, corrosion sensitization detection can be achieved by selecting the appropriate matrix material channel, precipitate element channel, auxiliary judgment channel, and background reference channel based on the matrix material elements, precipitate elements, and corresponding characteristic spectral lines, using the same system structure and detection process.

[0053] In summary, the multi-channel LIBS alloy corrosion sensitization detection system of the present invention, through redesign of its overall structure and working principle, can improve the efficiency, accuracy, stability and applicability of alloy corrosion sensitization detection by taking laser processing backlight self-calibration and multi-channel parallel beam splitting detection as its core, while improving the target band acquisition efficiency. By acquiring the actual laser excitation intensity and focus state information and combining it with multi-band signal calibration, it can significantly improve the efficiency, accuracy, stability and applicability of alloy corrosion sensitization detection. Compared with existing technologies, this invention effectively overcomes the technical pain points of insufficient detection efficiency, easy influence of laser intensity fluctuations and focus shift on detection results, and lack of actual processing state reference benchmarks for multi-channel signals. Therefore, it is particularly suitable for corrosion sensitization detection applications of aluminum-magnesium alloys, nickel-based alloys, stainless steel or other alloy materials, and has good practical value and application prospects.

[0054] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A self-calibrating multi-channel LIBS alloy material corrosion sensitization detection system, characterized in that, The system includes a laser excitation module, a multi-channel beam splitting detection module, a laser status monitoring module, a high-frequency acquisition module, and a signal processing module, wherein: The laser excitation module is used to emit a preset pulsed laser and focus it onto the surface of the alloy material (400) under test through an optical path to generate a plasma radiation signal. The laser return signal of the pulsed laser acting on the alloy material (400) under test returns along the original optical path. The laser state monitoring module (220) is used to collect the target signal corresponding to the laser wavelength in the laser backlight signal, and use it to characterize the excitation intensity and focal state of the pulsed laser actually acting on the surface of the alloy material (400) under test, and at the same time as subsequent self-calibration data; The multi-channel spectrophotometer (210) is used to receive the plasma radiation signal and separate it into multiple detection channels. The multiple detection channels include at least a matrix material channel and a precipitated phase element channel. The matrix material channel is used to collect the characteristic spectral line signals of the matrix material elements, and the precipitated phase element channel is used to collect the characteristic spectral line signals that correspond to each precipitated phase element. The high-frequency acquisition module is connected to the channel beam splitting detection module (210) and the laser status monitoring module (220) respectively, and is used to perform synchronous acquisition and digital processing of the target signal and the channel signals of each detection channel; The signal processing module (300) performs self-calibration on the channel signals of each detection channel based on the target signal to reduce the influence of laser intensity fluctuations and focus shifts. After completing the self-calibration, the channel signals are input into the recognition model to obtain the corrosion sensitization detection results.

2. The multi-channel LIBS alloy material corrosion sensitization detection system as described in claim 1, characterized in that, The laser excitation module includes a laser (100), a beam expander (101), a first reflector (102), a second reflector (103), a scanning galvanometer (104), a beam reducer (105), and an objective lens (106). The pulsed laser emitted by the laser (100) is shaped by the beam expander (101) and then reflected by the first reflector (102) and the second reflector (103) to the dichroic mirror (108). The dichroic mirror (108) reflects the pulsed laser, causing it to enter the scanning galvanometer (104) and be focused onto the surface of the alloy material (400) to be tested on the platform (107) after passing through the beam reducer (105) and the objective lens (106), thereby generating a plasma radiation signal. Meanwhile, the laser return signal returns along the original optical path, that is, it passes through the objective lens (106), the beam shrinking lens (105) and the scanning galvanometer (104) in sequence and then reaches the dichroic mirror (108) again. At this time, the target signal in the laser return signal corresponding to the laser wavelength is reflected by the dichroic mirror (108) into the laser state monitoring module (220), while other signals in the laser return signal are transmitted by the dichroic mirror (108) into the multi-channel beam splitting detection module (210).

3. The multi-channel LIBS alloy material corrosion sensitization detection system as described in claim 1 or 2, characterized in that, The laser status monitoring module (220) preferably includes an attenuator (221), a focusing lens (222), a pinhole aperture (223), and a detector (224) arranged sequentially along the optical path. The focusing lens (222) is used to focus the target signal to the position of the pinhole aperture (223) for limitation, and then the detector (224) receives it. When the laser focusing state of the alloy material (400) under test is normal, the laser return signal forms a concentrated spot near the pinhole aperture (223) after passing through the focusing lens (222), and is simultaneously received by the detector (224) and outputs the corresponding target signal; when the laser focus of the alloy material (400) under test deviates, the spot size and energy distribution of the laser return signal at the pinhole aperture (223) change, thereby causing the target signal output by the detector (224) to change accordingly.

4. The multi-channel LIBS alloy material corrosion sensitization detection system as described in any one of claims 1-3, characterized in that, The multi-channel beam splitting detection module (210) consists of a main optical path and multiple beam splitting links, wherein: A notch filter (212), multiple dichroic mirrors (2114), and a third mirror (2115) are sequentially arranged along the main optical path. The plasma radiation signal passes through the notch filter (212) to suppress the scattering interference of residual laser light, and then is split into various beam splitting links under the action of the multiple dichroic mirrors (2114) and the third mirror (2115). A narrow-band pass filter (2111), a focusing lens (2112), and a photodetector (2113) are sequentially arranged along each beam splitting link. Each of the narrow-band pass filters (2111) has a different center wavelength, thereby forming multiple detection channels corresponding to different wavebands. The beam splitting signals of each detection channel are focused by the focusing lens (2112) and then collected by the photodetector (2113).

5. The multi-channel LIBS alloy material corrosion sensitization detection system as described in claim 4, characterized in that, The multi-channel spectrophotometer (210) preferably further includes one or more auxiliary judgment channels, which are used to collect other characteristic spectral signals besides matrix material elements and precipitated phase elements, to enhance the auxiliary discrimination capability of corrosion sensitization detection results.

6. The multi-channel LIBS alloy material corrosion sensitization detection system as described in claim 4, characterized in that, For the multi-channel spectrophotometer (210), it preferably also includes a background reference channel, which is set to a band position that does not contain matrix material elements and precipitated phase elements, and acquires background band signals for the signal processing module (300) to perform timing alignment and / or amplitude normalization.

7. The multi-channel LIBS alloy material corrosion sensitization detection system as described in any one of claims 1-6, characterized in that, When the precipitated phase contains multiple elements, it is preferable to set the characteristic spectral line channel and / or auxiliary judgment channel corresponding to each precipitated element to achieve joint detection of different precipitated phase elements.

8. The channel LIBS alloy material corrosion sensitization detection system as described in any one of claims 1-7, characterized in that, The signal processing module (300) is preferably configured to include a recognition model such as a vector machine, artificial neural network, or random forest, and is used to input a multi-channel signal that has completed self-calibration, while outputting classification results, grade results, probability results, or quantitative results that reflect the corrosion sensitization of the alloy material.

9. The channel LIBS alloy material corrosion sensitization detection system as described in any one of claims 1-8, characterized in that, When the alloy material to be tested is an aluminum-magnesium alloy, the matrix material channel is configured to collect aluminum atomic spectral lines near 396 nm, and the precipitated phase element channel is configured to collect magnesium atomic spectral lines near 279 nm; when a background reference channel is set, the background reference channel is configured to collect continuous background radiation in the 290 nm to 300 nm band; when the multi-channel spectrophotometer (210) includes an auxiliary judgment channel, the auxiliary judgment channel is configured to collect magnesium atomic spectral lines near 285 nm.

10. A self-calibrated multi-channel LIBS alloy material corrosion sensitization detection method, characterized in that, It is executed using the system as described in any one of claims 1 to 9, comprising the following steps: A pulsed laser is focused onto the surface of the alloy material (400) to generate a plasma radiation signal, and the laser back signal generated by the pulsed laser is returned to the alloy material (400) along the original optical path. The laser state monitoring module (220) collects the target signal corresponding to the laser wavelength in the laser back signal, the multi-channel spectrophotometer (210) collects the characteristic spectral line signals of matrix material elements and precipitated phase elements in parallel, and the high-frequency acquisition module simultaneously collects the target signal and the channel signals of each detection channel and performs digital processing. The signal processing module (300) performs self-calibration on the channel signals of each detection channel based on the target signal, and inputs the self-calibrated channel signals of each detection channel into the recognition model to obtain the corrosion sensitization detection results.

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