Creep damage real-time monitoring method and device based on acoustic emission

Abstract

The invention provides a creep damage real-time monitoring method and device based on acoustic emission. The method comprises the following steps: collecting a first acoustic wave signal of a first sample based on acoustic emission in a first creep age forming process; and analyzing the corresponding relationship between the first sound wave signal and the creep time to obtain the corresponding damage occurrence time of the first sample in different creep damage stages. And microstructure data of the corresponding damage occurrence time of the second sample in the second creep age forming process is obtained. And establishing a mapping relation between the first sound wave signal and the creep damage situation to obtain a reference mapping relation. And in the forming process, process parameters of the third creep age forming are adjusted on the basis of the matching condition of the collected second sound wave signal and the reference mapping relation. According to the method, the internal microstructure evolution of the material in the creep aging process can be known through the change of the acoustic signal, and a large amount of research production time and production manufacturing cost are saved.

Description

Technical Field

[0001] The invention relates to the field of creep aging forming, and in particular to a method and a device for real-time monitoring of creep damage based on acoustic emission. Background Art

[0002] The basic experiment of creep aging is usually carried out in a creep machine. Specimens of different sizes are fixed on the control rod, and an extensometer is hung on the specimen or the strain of the specimen during creep aging is measured through video, and the creep performance of the specimen is analyzed through the collected data. However, during the creep aging experiment of the specimen, the specimen is often damaged or even broken due to inaccurate initial conditions. Although the optimal creep aging process of the specimen can be explored by continuously debugging the initial condition parameters, this method not only has low experimental efficiency and a large number of experimental specimens, but also can only infer the process parameters through the creep results, and cannot analyze the entire creep aging process.

[0003] At present, some technologies have been attempted to solve the above problems, such as the "Austenitic Steel Creep Damage Degree Detection Method" with publication number: CN 118655008 A applied by Guoneng Boiler and Pressure Vessel Inspection Co., Ltd. The method disclosed in this patent application is to establish a corresponding relationship between dislocation density and creep time and microstructure analysis to finally obtain the creep damage degree of austenitic steel. However, its invention is to make a physical correspondence between the damage and microstructure of different preset creep time, and it is impossible to monitor the material throughout the creep aging process, nor can it accurately capture when the material is damaged during the creep process.

[0004] In recent years, acoustic emission detection methods have been increasingly used in damage detection during the forming process. Sensors capture the acoustic wave signals of materials during deformation, analyze their frequency, amplitude and time domain characteristics, and determine the time when the material is damaged. For example, the "Prediction method, system and medium for the cause of creep damage of nickel-based high-temperature fastening bolts" with publication number: CN 118311150 A applied by the Inner Mongolia Electric Power Research Institute Branch of Inner Mongolia Electric Power (Group) Co., Ltd. The method disclosed in this patent application is to collect the temperature and vibration values ​​of the fastening bolts in real time, and predict the sliding cracking prediction time by combining the generated real-time vibration curve with the preset sliding cracking vibration curve, and determine the ductile fracture time of the fastening bolts in combination with the acoustic signal collection. However, the damage value detected by the acoustic emission equipment is only the result shown by the acoustic wave signal processing characteristics, and the actual damage of the material during the deformation process is not explored, resulting in the inability to scientifically adjust the creep process. That is, the conventional damage assessment method in the creep aging process cannot obtain the precise creep damage time and damage degree. Summary of the invention

[0005] The main purpose of the present invention is to provide a real-time monitoring method and device for creep damage based on acoustic emission, so as to solve the technical problem that the existing acoustic emission technology cannot obtain the accurate time and degree of creep damage.

[0006] To achieve the above object, the present invention provides a real-time monitoring method for creep damage based on acoustic emission, comprising the following steps: A first acoustic wave signal based on acoustic emission is collected during a first creep aging forming process of the first sample.

[0007] The corresponding relationship between the first acoustic wave signal and the creep time is analyzed to obtain the damage occurrence time corresponding to the first sample at different creep damage stages.

[0008] The microstructure data of the second samples at the corresponding damage occurrence times during the second creep aging forming process are respectively obtained, wherein the material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming and the first creep aging forming are the same.

[0009] Based on the first acoustic wave signal corresponding to the first sample at each damage occurrence time and the microstructure data corresponding to each of the second samples at each damage occurrence time, a mapping relationship between the first acoustic wave signal and the creep damage situation is established to obtain a reference mapping relationship.

[0010] The workpiece is subjected to a third creep aging forming while collecting a second acoustic wave signal corresponding to the acoustic emission, and the process parameters of the third creep aging forming are adjusted during the forming process based on the matching of the collected second acoustic wave signal with the reference mapping relationship, wherein the material of the workpiece is the same as that of the first sample.

[0011] According to an embodiment of the present application, the step of collecting a first acoustic wave signal based on acoustic emission of the first sample during a first creep aging forming process includes: Collecting points are set on the surface of the first sample, and the number of the collecting points is ≥1.

[0012] Under the condition of the set acoustic emission acquisition parameters, the first acoustic wave signal based on acoustic emission at the acquisition point during the first creep aging forming process of the first sample is collected. The acoustic emission acquisition parameters include at least one of gain decibel, sampling rate, sampling length, impact time, and peak definition time. The first acoustic wave signal includes at least one of amplitude, cumulative amplitude, ring count, energy, number of impacts, and cumulative number of impacts.

[0013] According to an embodiment of the present application, analyzing the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence time corresponding to the first sample at different creep damage stages includes: The creep damage stage of the first sample is determined according to the signal change of the first acoustic wave signal, and the corresponding creep time is recorded as the damage occurrence time. The signal change includes at least one of frequency change, amplitude change, and energy change.

[0014] According to an embodiment of the present application, the step of respectively obtaining microstructure data of each damage occurrence time corresponding to a plurality of second specimens during the second creep aging forming process includes: The second creep aging forming is performed on a plurality of second specimens respectively, and the forming is stopped when the corresponding damage occurs at each time.

[0015] Samples are taken from a plurality of second specimens after the second creep aging forming is stopped, and microstructure data thereof are determined.

[0016] According to an embodiment of the present application, the step of establishing a mapping relationship between the first acoustic wave signal and the creep damage situation based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times, and obtaining a reference mapping relationship includes: The corresponding creep damage conditions are determined according to the microstructure data corresponding to each of the second samples at each of the damage occurrence times. The microstructure data include at least one of the number of voids, void size, void distribution, precipitate size, precipitate distribution, number of precipitates, dislocation density, dislocation distribution, number of recrystallizations, and grain orientation.

[0017] The first acoustic wave signal of the first sample at the same damage occurrence time and the creep damage situation of the second sample at the same damage occurrence time are respectively associated and collected to obtain the reference mapping relationship.

[0018] According to an embodiment of the present application, the step of adjusting the process parameters of the third creep aging forming based on the matching of the second acoustic wave signal collected by acoustic emission and the reference mapping relationship during the forming process includes: The second acoustic wave signal of the workpiece based on acoustic emission is collected in real time, and matched with the reference mapping relationship.

[0019] If the second acoustic wave signal matches the first acoustic wave signal corresponding to the creep damage situation in the reference mapping relationship, the process parameters of the third creep aging forming are adjusted.

[0020] According to an embodiment of the present application, before the workpiece is subjected to the third creep aging forming step, the process further includes: Based on the reference mapping relationship, the process parameters of the first creep aging forming are adjusted to obtain initial process parameters of the third creep aging forming.

[0021] The present application also provides a real-time monitoring device for creep damage based on acoustic emission, comprising: The acoustic wave signal collection mechanism is used to collect the first acoustic wave signal of the first sample based on the first acoustic emission during the first creep aging forming process, and the second acoustic wave signal of the workpiece based on the acoustic emission during the third creep aging forming process.

[0022] The acoustic emission analysis mechanism is communicatively connected with the acoustic wave signal acquisition mechanism, and is used to analyze the corresponding relationship between the first acoustic wave signal and the creep time, obtain the damage occurrence time corresponding to the first sample at different creep damage stages, and determine the matching situation between the second acoustic wave signal and the reference mapping relationship in the third creep aging forming process.

[0023] The microstructure observation mechanism is used to obtain microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process. The material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming and the first creep aging forming are the same.

[0024] A creep mechanism is used to perform a first creep aging forming, a second creep aging forming and a third creep aging forming. The creep mechanism is also used to perform a third creep aging forming on the workpiece while collecting a second acoustic wave signal, and to adjust the process parameters of the third creep aging forming according to the matching of the second acoustic wave signal with the reference mapping relationship. The reference mapping relationship is a mapping relationship between the first acoustic wave signal and the creep damage situation established based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times.

[0025] According to the implementation of the present application, the acoustic wave signal acquisition mechanism includes a sensor and an amplifier, the amplifier is respectively connected to the sensor and the acoustic emission analysis mechanism, and the sensor is used to be placed on the first sample and the workpiece. The number of the sensors is ≥1, and the temperature range is -80℃~220℃. The gain amplification range of the amplifier is 20dB~60dB.

[0026] According to an implementation of the present application, the acoustic emission analysis mechanism includes an acoustic emission acquisition card, the number of the acoustic emission acquisition card is ≥1, the operating temperature is -30°C~70°C, and the bandwidth is 1khz~400khz.

[0027] In the above-mentioned real-time monitoring method of creep damage based on acoustic emission, on the basis of the first acoustic wave signal detection, a correspondence is established between the fluctuation information of the acoustic wave signal and the creep damage occurrence time by analyzing the fluctuation information of the acoustic wave signal, and then the microstructure evolution law under different damage occurrence times is determined. Finally, a correspondence is established between the acoustic wave signal and the microscopic damage evolution and used to guide the adjustment of the creep aging process. The internal microstructure evolution of the material during the creep aging process can be known through the change of the acoustic signal, so that the creep aging process parameters can be scientifically controlled in a more convenient and intuitive way, saving a lot of research and production time and production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0029] Figure 1 is a flow chart of a real-time monitoring method for creep damage based on acoustic emission according to an embodiment of the present application; Figure 2 It is a partial structural schematic diagram of a creep damage real-time monitoring device based on acoustic emission according to an embodiment of the present application.

[0030] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with the implementation methods and with reference to the accompanying drawings.

[0031] Description of reference numerals: 100, creep mechanism; 200, first sample; 300, acoustic wave signal acquisition mechanism; 310, sensor; 320, amplifier; 400, signal line; 500, acoustic emission analysis mechanism; 510, acoustic emission acquisition card; 520, calculation mechanism; 600, transmission line; 700, control rod. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that all directional indications (such as up, down, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0034] In addition, in the present invention, the descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0035] Furthermore, the technical solutions between the various embodiments of the present invention may be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in the field. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0036] The present invention provides a real-time monitoring method for creep damage based on acoustic emission. Figure 1 , including the following steps: S100: collecting a first acoustic wave signal based on acoustic emission during a first creep aging forming process of a first sample.

[0037] Metal creep aging is usually tested in a creep mechanism, such as when a sample is placed in a high-temperature environment box, and the sample is stretched or compressed by a control rod 700. In general creep aging experiments, the sample is often damaged or even broken due to inaccurate selection of experimental parameters. However, since the sample is placed in a high-temperature environment box, it is impossible to monitor the internal state of the sample in real time through external optical equipment. Therefore, the present application introduces an acoustic emission monitoring method during the creep aging of the sample, and records the acoustic phenomena of the sample during the creep aging process in the high-temperature environment box in real time in the form of electrical signals.

[0038] The principle of acoustic emission monitoring is: when a material is subjected to external force or internal stress, the defects or microcracks inside the material will be subjected to stress concentration, causing the local stress to exceed the yield strength of the material, resulting in plastic deformation or crack extension. In this process, the elastic energy inside the material will be released in the form of sound waves, forming an acoustic emission signal.

[0039] In step S100, a first acoustic wave signal of the first sample in the first creep aging forming process is collected according to the principle of acoustic emission.

[0040] The first sample is a sample of the same material as the target workpiece. There is no special requirement for the specific method of collecting the acoustic wave signal.

[0041] Exemplarily, the first sample is fixed on the creep mechanism, the extension device is connected, the sensor is fixed on the first sample, the sensor is connected to the amplifier through a signal line, and the amplifier is connected to the acoustic emission analysis mechanism through the signal line.

[0042] In some embodiments, the first sample is further subjected to surface polishing, and the surface polishing methods include but are not limited to sandpaper polishing, angle grinder polishing, and ion polishing.

[0043] The types of the first specimen include plate specimens and rod specimens. The types of the extensometers include mechanical tension and compression extensometers, video extensometers or clip-on extensometers.

[0044] S200: Analyze the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence time corresponding to the first sample at different creep damage stages.

[0045] The first acoustic wave signal is the signal of the first creep aging forming process, which is the continuous signal information in this time period. In the first creep aging forming process, including different damage stages, the first acoustic wave signal will show some changes, such as energy, frequency, amplitude and other signal data will change. At the same time, the moment when the signal data changes can also be recorded.

[0046] The moment when the first acoustic wave signal will have a large signal change (signal fluctuation) is usually when the corresponding sample is just damaged or develops into another stage of damage, and the signal fluctuation is more obvious and obviously different from the surrounding acoustic wave signals. The moment of signal fluctuation can be preliminarily judged as the time of damage occurrence in different creep damage stages.

[0047] Accordingly, the damage occurrence time of each creep damage stage can be understood as the moment or time period when the creep damage of this stage just occurs, rather than the complete duration of the creep damage of this stage. However, at this time, there is no corresponding microstructure data, so the creep damage stage cannot be accurately determined.

[0048] S300: respectively obtaining microstructure data of each damage occurrence time corresponding to a plurality of second samples in a second creep aging forming process, wherein the material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming and the first creep aging forming are the same.

[0049] Since the damage occurrence time has multiple moments, multiple second creep aging forming experiments need to be performed, and each damage occurrence time is analyzed. The number of second specimens is greater than or equal to the number of moments of the damage occurrence time.

[0050] Take the example of 3 moments when damage occurs, namely t1, t2, and t3. Therefore, different second specimens are required to carry out the second creep aging forming experiment with the same process parameters. For example, the microstructure data of a second specimen during the second creep aging forming process up to t1. The microstructure data of another second specimen during the second creep aging forming process up to t2. The microstructure data of another second specimen during the second creep aging forming process up to t3. Specifically, the second specimens are sampled and microstructures are observed to obtain the evolution law of the internal microstructure of the material at different creep damage times. The sampling and microstructure observation methods are not specifically limited.

[0051] In conventional experiments to obtain the degree of creep damage by analyzing the microstructure of materials under different creep processes, it is necessary to continuously conduct creep aging experiments with different processes to obtain specimens for microscopic observation, which cannot accurately capture the time corresponding to the creep damage of the material.

[0052] In this application, the experiment was conducted in combination with acoustic emission technology. Acoustic emission technology can monitor the acoustic wave signal of the sample throughout the creep aging process. By analyzing and recording the time when the acoustic signal fluctuation marks the creep damage, the creep process plan with different creep durations can be formulated based on this, which will greatly improve the efficiency of the microstructure analysis of the creep damage of the material and reduce the trial and error cost and the analysis and testing cost.

[0053] S400: Based on the first acoustic wave signal corresponding to the first sample at each damage occurrence time and the microstructure data corresponding to each of the second samples at each damage occurrence time, a mapping relationship between the first acoustic wave signal and the creep damage situation is established to obtain a reference mapping relationship.

[0054] The structure of the second sample is the same as or different from that of the first sample. Since the material of the second sample is the same as that of the first sample, the process parameters of the second creep aging forming and the first creep aging forming are the same. Therefore, at the same damage occurrence time, the microstructure data of the second sample can be considered to be basically the same as the microstructure data of the first sample. In this way, the first acoustic wave signal of the first sample is associated with the creep damage situation, and a mapping relationship is established between the two to obtain a reference mapping relationship. The reference mapping relationship can be applied to the creep aging forming process of the corresponding material of the first sample.

[0055] S500: Performing a third creep aging forming on the workpiece while collecting a second acoustic wave signal corresponding to acoustic emission, and adjusting the process parameters of the third creep aging forming based on the matching of the collected second acoustic wave signal with the reference mapping relationship during the forming process, wherein the material of the workpiece is the same as that of the first sample.

[0056] In this step, the initial process parameters of the third creep aging forming can be the same as or different from the process parameters of the first creep aging forming. The structure of the workpiece can be the same as or different from the structure of the first sample.

[0057] During the third creep aging forming process, acoustic emission monitoring is performed. Acoustic emission monitoring is used to guide the adjustment of the process parameters of the third creep aging forming process. For example, when the collected second acoustic wave signal is close to the acoustic wave signal when creep damage occurs in the reference mapping relationship, the process parameters are adjusted to avoid the creep damage.

[0058] In the above-mentioned real-time monitoring method of creep damage based on acoustic emission, on the basis of the first acoustic wave signal detection, a correspondence is established between the fluctuation information of the acoustic wave signal and the creep damage occurrence time by analyzing the fluctuation information of the acoustic wave signal, and then the microstructure evolution law under different damage occurrence times is determined. Finally, a correspondence is established between the acoustic wave signal and the microscopic damage evolution and used to guide the adjustment of the creep aging process. The internal microstructure evolution of the material during the creep aging process can be known through the change of the acoustic signal, so that the creep aging process parameters can be scientifically controlled in a more convenient and intuitive way, saving a lot of research and production time and production costs.

[0059] In some embodiments, the step of collecting a first acoustic wave signal based on acoustic emission during the first creep aging forming process of the first sample comprises: Collecting points are set on the surface of the first sample, and the number of the collecting points is ≥1.

[0060] For example, sensors are placed on the surface of the first sample. When the surface of the first sample is larger, the number of sensors is appropriately increased.

[0061] Under the condition of the set acoustic emission acquisition parameters, the first acoustic wave signal based on acoustic emission at the acquisition point during the first creep aging forming process of the first sample is collected. The acoustic emission acquisition parameters include at least one of gain decibel, sampling rate, sampling length, impact time, and peak definition time. The first acoustic wave signal includes at least one of amplitude, cumulative amplitude, ring count, energy, number of impacts, and cumulative number of impacts.

[0062] Under this condition, a richer variety of acoustic wave signal parameters are obtained, which facilitates subsequent analysis based on the fluctuation of one or several acoustic wave signal parameters and more accurately obtains the signal change of the first acoustic wave signal.

[0063] In some embodiments, analyzing the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence time corresponding to the first sample at different creep damage stages includes: The creep damage stage of the first sample is determined according to the signal change of the first acoustic wave signal, and the corresponding creep time is recorded as the damage occurrence time. The signal change includes at least one of frequency change, amplitude change, and energy change.

[0064] This method can accurately identify and determine information such as the time and duration of a significant signal change, thereby accurately determining the creep damage stage.

[0065] In some embodiments, the step of respectively acquiring microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process comprises: The second creep aging forming is performed on a plurality of second specimens respectively, and the forming is stopped when the corresponding damage occurs at each time.

[0066] Samples are taken from a plurality of second specimens after the second creep aging forming is stopped, and microstructure data thereof are determined.

[0067] In this embodiment, each second sample is subjected to the experiment until the damage occurrence time corresponding to the second creep aging forming is reached, and then the microstructure data is sampled and observed. The observation method of the microstructure observation includes any one of OM, SEM, EBSD, TEM, XRD, 3D-XRD, and 3D-CT. That is, the damage occurrence time corresponding to the first sample at different creep damage stages is used as a guide, and the sampling and analysis are carried out more accurately in each second creep aging forming experiment, thereby improving the accuracy of the results.

[0068] In some embodiments, the step of establishing a mapping relationship between the first acoustic wave signal and the creep damage situation based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times to obtain a reference mapping relationship includes: The corresponding creep damage conditions are determined according to the microstructure data corresponding to each of the second samples at each of the damage occurrence times. The microstructure data include at least one of the number of voids, void size, void distribution, precipitate size, precipitate distribution, number of precipitates, dislocation density, dislocation distribution, number of recrystallizations, and grain orientation.

[0069] The first acoustic wave signal of the first sample at the same damage occurrence time and the creep damage situation of the second sample at the same damage occurrence time are respectively associated and collected to obtain the reference mapping relationship.

[0070] The creep damage condition of the second sample is determined based on one or more of the different types of microstructure data, and is associated with the first acoustic wave signal. All different creep damage conditions are associated with the corresponding first acoustic wave signal to obtain a reference mapping relationship. The reference mapping relationship can be input into the control device of the creep machine to facilitate the adjustment of process parameters during subsequent creep aging forming.

[0071] In some embodiments, the step of adjusting the process parameters of the third creep aging forming based on the matching of the second acoustic wave signal collected by acoustic emission and the reference mapping relationship during the forming process includes: The second acoustic wave signal of the workpiece based on acoustic emission is collected in real time, and matched with the reference mapping relationship.

[0072] If the second acoustic wave signal matches the first acoustic wave signal corresponding to the creep damage situation in the reference mapping relationship, the process parameters of the third creep aging forming are adjusted.

[0073] This method collects the second acoustic wave signal in real time and matches it with the reference mapping relationship. If it is consistent with or close to the first acoustic wave signal corresponding to the creep damage situation, the process parameters of the third creep aging forming are adjusted to avoid creep damage on the workpiece or reduce the probability of creep damage.

[0074] In some embodiments, before the workpiece is subjected to the third creep aging forming step, the method further comprises: Based on the reference mapping relationship, the process parameters of the first creep aging forming are adjusted to obtain initial process parameters of the third creep aging forming.

[0075] In some cases, if it can be determined based on the reference mapping relationship that the design process parameters of the third creep aging forming have the risk of creep damage, the process parameters can be adjusted in advance before the third creep aging forming step is performed, so that the number of adjustments during the third creep aging forming process is reduced, thereby improving the forming efficiency.

[0076] In general, the above-mentioned real-time monitoring method of creep damage based on acoustic emission has the following beneficial effects: 1. Compared with the traditional creep damage time obtained by testing materials through different creep processes, acoustic emission technology can carry out real-time monitoring of the internal acoustic signals of the sample during the creep aging process. Through the fluctuation analysis of the acoustic wave signal, the time when the material produces creep damage during the creep aging process can be more accurately captured, which improves the research efficiency of the material creep damage process and saves a lot of research time and sample production costs.

[0077] 2. To obtain the degree of creep damage by analyzing the microstructure of materials under different creep processes, it is necessary to continuously conduct creep aging experiments with different processes to obtain samples for microscopic observation, which cannot accurately capture the time corresponding to the creep damage of the material. Acoustic emission technology can monitor the acoustic signal of the sample throughout the creep aging process, and analyze and record the time and degree of creep damage by recording the fluctuation of the acoustic signal. Based on this, the creep process plan with different creep durations can be formulated, which will greatly improve the efficiency of the microstructure analysis of creep damage of the material and reduce the trial and error cost and analysis and testing cost.

[0078] 3. Compared with the traditional method of monitoring the creep aging process of materials only by acoustic emission technology, the method of the present invention, based on the detection of acoustic wave signals, establishes a corresponding relationship between the fluctuation information of the acoustic wave signals and the creep damage time, and seeks the evolution law of the microstructure under different creep damage times. Finally, the acoustic signal and the evolution of microdamage are correspondingly related and used to guide the adjustment of the creep aging process. A scientific explanation of creep damage is given from the microscopic level, and a corresponding relationship between the creep damaged microstructure and the acoustic signal is established, so that the creep damaged microstructure is "visualized". The internal microstructure evolution of the material during the creep aging process can be known through the changes in the acoustic signal, so as to scientifically regulate the creep aging process parameters more conveniently and intuitively.

[0079] The present application also provides a real-time monitoring device for creep damage based on acoustic emission, see Figure 2 ,include: The acoustic wave signal collecting mechanism 300 is used to collect the first acoustic wave signal of the first sample based on the first acoustic emission during the first creep aging forming process, and the second acoustic wave signal of the workpiece based on the acoustic emission during the third creep aging forming process.

[0080] The acoustic emission analysis mechanism 500 is communicatively connected with the acoustic wave signal acquisition mechanism 300, and is used to analyze the corresponding relationship between the first acoustic wave signal and the creep time, obtain the damage occurrence time corresponding to the first sample at different creep damage stages, and determine the matching situation of the second acoustic wave signal and the reference mapping relationship in the third creep aging forming process.

[0081] A microstructure observation mechanism is used to obtain microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process. The material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming and the first creep aging forming are the same. For example, the microstructure observation mechanism includes any one of OM, SEM, EBSD, TEM, XRD, 3D-XRD, and 3D-CT mechanisms.

[0082] The creep mechanism 100 is used to perform the first creep aging forming, the second creep aging forming and the third creep aging forming. The creep mechanism 100 is also used to perform the third creep aging forming on the workpiece while collecting the second acoustic wave signal, and adjust the process parameters of the third creep aging forming according to the matching of the second acoustic wave signal with the reference mapping relationship. The reference mapping relationship is a mapping relationship between the first acoustic wave signal and the creep damage situation established based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times.

[0083] The above-mentioned real-time monitoring device for creep damage based on acoustic emission adopts the above-mentioned real-time monitoring method for creep damage based on acoustic emission, and therefore has corresponding technical effects, so it will not be described in detail.

[0084] In some embodiments, the acoustic wave signal acquisition mechanism 300 includes a sensor 310 and an amplifier 320, and the amplifier 320 is respectively connected to the sensor 310 and the acoustic emission analysis mechanism 500 for communication, and the sensor 310 is used to be placed on the first sample and the workpiece. The number of the sensors 310 is ≥ 1, and the temperature range is -80°C to 220°C. The gain amplification range of the amplifier 320 is 20dB to 60dB.

[0085] The size of the sensor 310 is selected according to the area where the sample can be placed. For example, the sensor 310 is connected to the amplifier 320 via a signal line 400 , and the amplifier 320 is connected to the acoustic emission analysis mechanism 500 via the signal line 400 .

[0086] In some embodiments, the acoustic emission analysis mechanism 500 includes an acoustic emission acquisition card 510 , the number of the acoustic emission acquisition card 510 is ≥ 1, the operating temperature is -30°C~70°C, and the bandwidth is 1khz~400khz.

[0087] In some embodiments, the acoustic emission analysis mechanism 500 includes, in addition to the acoustic emission acquisition card 510, an AD converter and a computing mechanism 520 capable of running an acoustic emission analysis executable program, such as a calculator. The AD converter can convert analog signals into data signals. The acoustic emission acquisition card 510 is connected to the computing mechanism 520 via a transmission line 600 to transmit data. The computing mechanism 520 analyzes the acoustic wave signals collected by the acoustic emission acquisition card 510.

[0088] The technical solution of the present application is described below in conjunction with specific embodiments.

[0089] A real-time monitoring method for creep damage based on acoustic emission comprises the following steps: Q1: Surface treatment is performed on the first sample, the first sample is fixed on the creep machine, two pairs of upper and lower extension rods are installed on the sample, an extensometer is installed on the extension rod to measure deformation, a sensor is fixed on the first sample, the sensor and the sample are connected with a coupling agent, and the sensor position is reinforced with high-temperature glue, the sensor is connected to the amplifier through a signal line, the amplifier is connected to the acoustic emission analysis system through a signal line, and the acoustic emission analysis system is connected to the acoustic emission analysis software with a transmission line. The acoustic emission analysis system includes an acoustic emission acquisition card, an AD converter, and a computing mechanism capable of running an acoustic emission analysis executable program.

[0090] The material of the first sample is 7xxx series high-strength aluminum alloy with a thickness of 2 mm, and the sample type is a plate sample. The heat treatment state is an over-aging state, and the surface is rough ground, fine ground, and mechanically polished.

[0091] The strain in the creep aging process was measured using a mechanical tension and compression extensometer. The creep aging process parameters were creep time 140°C, creep stress 350MPa, heating rate 5°C / min, and loading rate 15N / s.

[0092] The number of sensors is 2, and the size is , temperature range is -65℃-177℃, detection frequency band is 50kHz-400kHz.

[0093] The acoustic emission acquisition parameters were set as gain decibel 40 dB, sampling rate 2000 kHz, sampling length 2000 points, impact time 2000 us, and peak definition time 1000 us.

[0094] Q2: Set the first creep aging process parameters on the creep mechanism, and turn on the acoustic signal acquisition mechanism and acoustic emission analysis mechanism. Set the acoustic emission acquisition parameters, and start the creep machine, acoustic signal acquisition mechanism and acoustic emission analysis mechanism at the same time to start the creep aging experiment of the first sample.

[0095] Among them, the creep aging process parameters specifically include creep temperature, heating rate, creep holding time, load size, and loading rate.

[0096] Among them, the acoustic emission acquisition parameters include gain decibel, sampling rate, sampling length, impact time, and peak definition time.

[0097] Q3: After the first creep aging is completed, the furnace is opened to cool down, the high temperature glue is torn off, the sensor on the first sample is removed, and the first sample is removed. The corresponding relationship between the acoustic wave signal and the creep time is analyzed in the acoustic emission analysis software of the acoustic emission analysis agency, and the starting time of creep damage and the change law of the acoustic wave signal during the creep damage process are obtained and recorded.

[0098] Among them, the sound wave signal includes amplitude, cumulative amplitude, ringing count, energy, number of impacts, cumulative number of impacts, etc.

[0099] Q4: According to the change law of the acoustic wave signal in the creep damage process obtained in Q3, the corresponding relationship between the damage occurrence time and the damage degree in the creep damage process is obtained, and the creep aging process plan with different creep times (from the start of the second creep aging forming to the occurrence time of each damage) in the second creep aging forming is formulated based on this.

[0100] Q5: Prepare the corresponding number of samples according to the number of process plans formulated in Q4, carry out creep aging experiments with different creep times, and observe the microstructure of the deformation zone of the specimens of each creep process to obtain the evolution law of the internal microstructure of the material under different creep damage times.

[0101] Among them, microstructure observation, its observation methods include OM, SEM, EBSD, TEM, XRD, 3D-XRD, and 3D-CT.

[0102] Among them, the microstructure observation includes the number of voids, void size, void distribution, precipitate phase size, precipitate phase distribution, number of precipitate phases, dislocation density, dislocation distribution, recrystallization amount, and grain orientation.

[0103] Q6: Set a corresponding relationship between the changing law of the acoustic wave signal during the creep damage process in Q3 and the evolution law of the microstructure in Q5, construct an acoustic wave signal-microstructure mapping relationship diagram, and obtain the internal acoustic signal results of materials with different degrees of damage to guide the formulation of creep aging process parameters.

[0104] The above technical solutions of the present invention are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereto. All equivalent structural changes made by using the contents of the present invention specification and drawings under the technical concept of the present invention, or directly / indirectly applied in other related technical fields are included in the protection scope of the present invention.

Claims

1. A real-time monitoring method for creep damage based on acoustic emission, characterized in that: The following steps are involved: Collecting a first acoustic wave signal based on acoustic emission during a first creep aging forming process of the first sample; Analyzing the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence time corresponding to different creep damage stages of the first sample; Respectively obtaining microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process; wherein the material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming and the first creep aging forming are the same; Based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times, a mapping relationship between the first acoustic wave signal and the creep damage situation is established to obtain a reference mapping relationship; The workpiece is subjected to a third creep aging forming while collecting a second acoustic wave signal corresponding to acoustic emission, and during the forming process, the process parameters of the third creep aging forming are adjusted based on the matching of the collected second acoustic wave signal with the reference mapping relationship; wherein the material of the workpiece is the same as that of the first sample.

2. The real-time monitoring method for creep damage based on acoustic emission according to claim 1 is characterized in that: The step of collecting a first acoustic wave signal based on acoustic emission during a first creep aging forming process of the first sample comprises: Setting collection points on the surface of the first sample; the number of the collection points is ≥ 1; Under the condition of the set acoustic emission acquisition parameters, a first acoustic wave signal based on acoustic emission at the acquisition point is collected during the first creep aging forming process of the first sample; wherein the acoustic emission acquisition parameters include at least one of gain decibel, sampling rate, sampling length, impact time, and peak definition time; and the first acoustic wave signal includes at least one of amplitude, cumulative amplitude, ringing count, energy, number of impacts, and cumulative number of impacts.

3. The real-time monitoring method for creep damage based on acoustic emission according to claim 1 is characterized in that: The analyzing the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence time corresponding to the first sample at different creep damage stages includes: According to the signal change of the first acoustic wave signal, the creep damage stage of the first sample is determined, and the corresponding creep time is recorded as the damage occurrence time; the signal change includes at least one of frequency change, amplitude change, and energy change.

4. The real-time monitoring method for creep damage based on acoustic emission according to claim 1 is characterized in that: The step of respectively obtaining microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process comprises: Performing second creep aging forming on a plurality of second specimens respectively, and stopping the forming when the corresponding damage occurs at each time; Samples are taken from a plurality of second specimens after the second creep aging forming is stopped, and microstructure data thereof are determined.

5. The real-time monitoring method for creep damage based on acoustic emission according to claim 1 is characterized in that: The step of establishing a mapping relationship between the first acoustic wave signal and the creep damage situation based on the first acoustic wave signal corresponding to the first sample at each damage occurrence time and the microstructure data corresponding to each second sample at each damage occurrence time to obtain a reference mapping relationship comprises: Determine the corresponding creep damage situation according to the microstructure data corresponding to each of the second samples at each of the damage occurrence times; the microstructure data includes at least one of the number of voids, void size, void distribution, precipitate size, precipitate distribution, number of precipitates, dislocation density, dislocation distribution, number of recrystallizations, and grain orientation; The first acoustic wave signal of the first sample at the same damage occurrence time and the creep damage situation of the second sample at the same damage occurrence time are respectively associated and collected to obtain the reference mapping relationship.

6. The real-time monitoring method for creep damage based on acoustic emission according to claim 1 is characterized in that: The step of adjusting the process parameters of the third creep aging forming based on the matching of the second acoustic wave signal collected by acoustic emission and the reference mapping relationship during the forming process includes: collecting a second acoustic wave signal of the workpiece based on acoustic emission in real time, and matching it with the reference mapping relationship; If the second acoustic wave signal matches the first acoustic wave signal corresponding to the creep damage situation in the reference mapping relationship, the process parameters of the third creep aging forming are adjusted.

7. The real-time monitoring method for creep damage based on acoustic emission according to any one of claims 1 to 6, characterized in that: Before the workpiece is subjected to the third creep aging forming step, the step further includes: Based on the reference mapping relationship, the process parameters of the first creep aging forming are adjusted to obtain initial process parameters of the third creep aging forming.

8. A real-time monitoring device for creep damage based on acoustic emission, characterized in that: include: An acoustic wave signal collection mechanism, used for collecting a first acoustic wave signal of the first sample based on the first acoustic emission during the first creep aging forming process, and a second acoustic wave signal of the workpiece based on the acoustic emission during the third creep aging forming process; An acoustic emission analysis mechanism, which is in communication connection with the acoustic wave signal acquisition mechanism, is used to analyze the corresponding relationship between the first acoustic wave signal and the creep time, obtain the damage occurrence time corresponding to the first sample at different creep damage stages, and determine the matching situation between the second acoustic wave signal and the reference mapping relationship in the third creep aging forming process; A microstructure observation mechanism, used to respectively obtain microstructure data of each damage occurrence time corresponding to a plurality of second samples during the second creep aging forming process; The material of the second sample is the same as that of the first sample, and the process parameters of the second creep aging forming are the same as those of the first creep aging forming; A creep mechanism is used to perform a first creep aging forming, a second creep aging forming and a third creep aging forming; the creep mechanism is also used to perform a third creep aging forming on the workpiece while collecting a second acoustic wave signal, and adjust the process parameters of the third creep aging forming according to the matching of the second acoustic wave signal with a reference mapping relationship; wherein the reference mapping relationship is a mapping relationship between the first acoustic wave signal and the creep damage situation established based on the first acoustic wave signal corresponding to each of the damage occurrence times of the first sample and the microstructure data corresponding to each of the second samples at each of the damage occurrence times.

9. The real-time monitoring device for creep damage based on acoustic emission according to claim 8, characterized in that: The acoustic wave signal acquisition mechanism includes a sensor and an amplifier, the amplifier is respectively connected to the sensor and the acoustic emission analysis mechanism for communication, the sensor is used to be placed on the first sample and the workpiece; the number of the sensors is ≥1, and the temperature resistance range is -80°C~220°C; the gain amplification range of the amplifier is 20dB~60dB.

10. The real-time monitoring device for creep damage based on acoustic emission according to claim 8 or 9, characterized in that: The acoustic emission analysis mechanism includes an acoustic emission acquisition card, the number of the acoustic emission acquisition card is ≥1, the operating temperature is -30°C to 70°C, and the bandwidth is 1khz to 400khz.

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