Real-time monitoring method and device for creep damage based on acoustic emission

Abstract

The present invention provides a method and device for real-time monitoring of creep damage based on acoustic emission. The method comprises the following steps: collecting a first acoustic wave signal based on acoustic emission during a first creep aging forming process of a first sample. Analyzing the correspondence between the first acoustic wave signal and the creep time, obtaining the damage occurrence time corresponding to different creep damage stages of the first sample. Obtaining the microstructure data of each damage occurrence time corresponding to the second sample during the second creep aging forming process respectively. Thus, a mapping relationship between the first acoustic wave signal and the creep damage situation is established, and a reference mapping relationship is obtained. 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 and the reference mapping relationship. The above method can know the internal microstructure evolution of the material during the creep aging process through the change of the acoustic signal, saving a lot of research and production time and production costs.

Description

Technical Field

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

[0002] Basic creep age experiments are usually carried out in a creep machine. Specimens of different sizes are fixed on a control rod, and an extensometer is hung on the specimen or the strain of the specimen during creep age is measured through video. The creep performance of the specimen is analyzed through the collected data. However, during the creep age experiment of the specimen, due to inaccurate initial condition settings, the specimen often suffers damage or even fracture during the creep age process. Although the optimal creep age 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 from the creep results and cannot perform a full-process analysis of the creep age process.

[0003] At present, some technologies have tried to solve the above problems. For example, in the "Method for Detecting Creep Damage Degree of Austenitic Steel" with publication number CN 118655008 A, the method disclosed in this patent application obtains the creep damage degree of austenitic steel by establishing the corresponding relationship between dislocation density and creep duration and microstructure analysis. However, its invention makes a physical correspondence between the damage and microstructure of different preset creep durations, and cannot monitor the whole process of the material during creep age, nor can it accurately capture when the material is damaged during the creep process.

[0004] In recent years, acoustic emission detection means have been increasingly used in damage detection during the forming process. By capturing the acoustic wave signals of the material during the deformation process through sensors, analyzing their frequency, amplitude and time-domain characteristics, and judging the time when the material is damaged. For example, in the "Method, System and Medium for Predicting Creep Damage Causes of Nickel-Based High-Temperature Fastening Bolts" with publication number CN 118311150 A, the method disclosed in this patent application is to collect the temperature value and vibration value of the fastening bolt in real time, 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 bolt by combining acoustic signal acquisition. However, the damage value detected by the acoustic emission device is only the result shown by the processing characteristics of the acoustic wave signal, and does not explore the actual damage situation of the material during the deformation process, resulting in the inability to scientifically adjust the creep process. That is, the conventional damage assessment method during the creep age process cannot obtain the accurate time and degree of creep damage. Summary of the Invention

[0005] The main object of the present invention is to provide a method and device for real-time monitoring of creep damage based on acoustic emission 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:

[0007] Collect the first acoustic wave signal based on acoustic emission during the first creep age forming process of the first specimen.

[0008] Analyze the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence times corresponding to different creep damage stages of the first specimen.

[0009] Respectively obtain the microstructural data of the damage occurrence times corresponding to multiple second specimens during the second creep age forming process. Wherein, the material of the second specimen is the same as that of the first specimen, and the process parameters of the second creep age forming and the first creep age forming are the same.

[0010] Based on the first acoustic wave signal corresponding to each damage occurrence time of the first specimen and the microstructural data corresponding to each damage occurrence time of each second specimen, establish the mapping relationship between the first acoustic wave signal and the creep damage situation to obtain the reference mapping relationship.

[0011] Perform the third creep age forming on the workpiece under the condition of collecting the second acoustic wave signal based on acoustic emission, and adjust the process parameters of the third creep age forming based on the matching situation between the collected second acoustic wave signal and the reference mapping relationship during the forming process. Wherein, the material of the workpiece is the same as that of the first specimen.

[0012] According to the embodiment of the present application, the step of collecting the first acoustic wave signal based on acoustic emission during the first creep age forming process of the first specimen includes:

[0013] Set collection points on the surface of the first specimen. The number of the collection points ≥ 1.

[0014] Under the condition of the set acoustic emission collection parameters, collect the first acoustic wave signal based on acoustic emission at the collection points during the first creep age forming process of the first specimen. Wherein, the acoustic emission collection parameters include at least one of gain in decibels, 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.

[0015] According to the embodiment of the present application, the step of analyzing the corresponding relationship between the first acoustic wave signal and the creep time to obtain the damage occurrence times corresponding to different creep damage stages of the first specimen includes:

[0016] Determine the creep damage stage of the first specimen according to the signal change of the first acoustic wave signal, and record the corresponding creep time as the damage occurrence time. The signal change includes at least one of frequency change, amplitude change, and energy change.

[0017] According to an embodiment of the present application, the step of respectively obtaining the microstructure data of each damage occurrence time corresponding to a plurality of second specimens during the second creep aging forming process includes:

[0018] Perform second creep aging forming on a plurality of second specimens respectively, and stop when reaching the corresponding damage occurrence time for each.

[0019] Take samples respectively on the second specimens after stopping the second creep aging forming for a plurality of times, and determine the microstructure data therein.

[0020] According to an embodiment of the present application, the step of establishing the mapping relationship between the first acoustic wave signal and the creep damage situation based on the first acoustic wave signal corresponding to the first specimen at each damage occurrence time and the microstructure data corresponding to each second specimen at each damage occurrence time to obtain the reference mapping relationship includes:

[0021] Determine the corresponding creep damage situation according to the microstructure data corresponding to each second specimen at each damage occurrence time. The microstructure data includes at least one of the number of voids, void size, void distribution, precipitate size, precipitate distribution, precipitate number, dislocation density, dislocation distribution, recrystallization number, and grain orientation.

[0022] After associating the first acoustic wave signal of the first specimen and the creep damage situation of the second specimen at the same damage occurrence time respectively, gather them to obtain the reference mapping relationship.

[0023] 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 situation between the second acoustic wave signal collected by acoustic emission during the forming process and the reference mapping relationship includes:

[0024] Collect the second acoustic wave signal of the workpiece based on acoustic emission in real time, and match it with the reference mapping relationship.

[0025] If the second acoustic wave signal matches the first acoustic wave signal corresponding to the creep damage situation in the reference mapping relationship, adjust the process parameters of the third creep aging forming.

[0026] According to an embodiment of the present application, before the step of performing the third creep aging forming on the workpiece, it further includes:

[0027] Based on the reference mapping relationship, adjust the process parameters of the first creep age forming to obtain the initial process parameters of the third creep age forming.

[0028] This application also provides a real-time monitoring device for creep damage based on acoustic emission, including:

[0029] An acoustic wave signal acquisition mechanism for acquiring a first acoustic wave signal based on the first acoustic emission during the first creep age forming of a first specimen, and a second acoustic wave signal based on acoustic emission during the third creep age forming of a workpiece.

[0030] An acoustic emission analysis mechanism, communicatively connected to the acoustic wave signal acquisition mechanism, for analyzing the correspondence between the first acoustic wave signal and the creep time, obtaining the damage occurrence times corresponding to different creep damage stages of the first specimen, and determining the matching situation between the second acoustic wave signal and the reference mapping relationship during the third creep age forming process.

[0031] A microstructure observation mechanism for respectively obtaining the microstructure data of multiple second specimens corresponding to each damage occurrence time during the second creep age forming process. The material of the second specimen is the same as that of the first specimen, and the process parameters of the second creep age forming and the first creep age forming are the same.

[0032] A creep mechanism for performing the first creep age forming, the second creep age forming, and the third creep age forming. The creep mechanism is further configured to perform the third creep age forming on the workpiece in the case of acquiring the second acoustic wave signal, and adjust the process parameters of the third creep age forming according to the matching situation between the second acoustic wave signal and the 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 damage occurrence time of the first specimen, and the microstructure data of each second specimen corresponding to each damage occurrence time.

[0033] According to an embodiment of the present application, the acoustic wave signal acquisition mechanism includes a sensor and an amplifier. The amplifier is communicatively connected to the sensor and the acoustic emission analysis mechanism respectively. The sensor is used to be placed on the first specimen and the workpiece. The number of the sensors is ≥1, and the temperature resistance range is -80°C to 220°C. The gain amplification range of the amplifier is 20dB to 60dB.

[0034] According to an embodiment of the present application, the acoustic emission analysis mechanism includes an acoustic emission acquisition card. The number of the acoustic emission acquisition cards is ≥1, the operating temperature is -30°C to 70°C, and the bandwidth is 1kHz to 400kHz.

[0035] In the above real-time monitoring method for creep damage based on acoustic emission, on the basis of detecting the first acoustic wave signal, a corresponding relationship is established by analyzing the fluctuation information of the acoustic wave signal and the occurrence time of creep damage, and then the evolution law of the microstructure at different damage occurrence times is determined. Finally, a corresponding relationship is generated 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 understood through the change of the acoustic signal, so as to more conveniently and intuitively scientifically control the creep aging process parameters, saving a large amount of research and production time and production costs. Brief Description of the Drawings

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

[0037] Figure 1 is a flowchart of a real-time monitoring method for creep damage based on acoustic emission according to an embodiment of the present application;

[0038] Figure 2 is a partial structural schematic diagram of a real-time monitoring device for creep damage based on acoustic emission according to an embodiment of the present application.

[0039] The realization of the object, functional features, and advantages of the present invention will be further described in conjunction with the embodiments with reference to the drawings.

[0040] Description of the Reference Numerals in the Drawings:

[0041] 100, creep mechanism; 200, first specimen; 300, acoustic wave signal acquisition mechanism; 310, sensor; 320, amplifier; 400, signal line; 500, acoustic emission analysis mechanism; 510, acoustic emission acquisition card; 520, computer; 600, transmission line; 700, control rod. Detailed Embodiments

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0043] It should be noted that all the directional indications (such as up, down,...) in the embodiments of the present invention are only used to explain the relative positional relationship, movement conditions, etc. between components in a specific posture (as shown in the attached drawings). If the specific posture changes, the directional indications will also change accordingly.

[0044] In addition, in the present invention, descriptions such as "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features.

[0045] Moreover, the technical solutions between various embodiments of the present invention can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0046] The present invention provides a real-time monitoring method for creep damage based on acoustic emission. Refer to Figure 1 , including the following steps:

[0047] S100: Collect the first acoustic wave signal based on acoustic emission during the first creep age forming process of the first specimen.

[0048] Metal creep age is usually experimented in a creep mechanism. For example, the specimen is placed in a high-temperature environmental chamber, and the specimen is driven to be stretched or compressed by a control rod 700 up and down. During the general creep age experiment process, due to inaccurate selection of experimental parameters, the specimen may be damaged or even fractured. However, since the specimen is placed in a high-temperature environmental chamber, it is impossible to monitor the internal state of the specimen in real time through external optical equipment. Therefore, in the process of specimen creep age in this application, an acoustic emission monitoring means is introduced to record the acoustic phenomenon during the creep age process of the specimen in the high-temperature environmental chamber in the form of an electrical signal in real time.

[0049] The principle of acoustic emission monitoring is as follows: When a material is subjected to an external force or internal stress, defects or microcracks inside the material will be subjected to stress concentration, resulting in local stress exceeding the yield strength of the material, generating plastic deformation or crack propagation. In this process, the elastic energy inside the material will be released in the form of sound waves to form an acoustic emission signal.

[0050] In step S100, the first acoustic wave signal during the first creep age forming process of the first specimen is collected according to the principle of acoustic emission.

[0051] The first specimen is a specimen with the same material as the target workpiece. There are no special requirements for the specific method of collecting the acoustic wave signal.

[0052] Exemplarily, fix the first specimen on the creep mechanism, connect the extensometer, fix the sensor on the first specimen, connect the sensor and the amplifier through a signal line, and connect the amplifier to the acoustic emission analysis mechanism through a signal line.

[0053] In some embodiments, it further includes surface polishing treatment of the first specimen, and the surface polishing treatment methods include but are not limited to sandpaper grinding, angle grinder grinding, and ion polishing.

[0054] The types of the first specimen include plate specimens and rod specimens. The types of the extensometer include mechanical tensile-compressive extensometers, video extensometers, or clip-on extensometers.

[0055] S200: Analyze the correspondence between the first acoustic wave signal and the creep time, and obtain the damage occurrence time corresponding to different creep damage stages of the first specimen.

[0056] The first acoustic wave signal is the signal of the first creep age forming process and is the continuous signal information during this time period. During the first creep age forming process, which includes different damage stages, the first acoustic wave signal will show some changes, such as signal data such as energy, frequency, and amplitude will change. At the same time, the moments when the signal data changes can also be recorded.

[0057] The moments when the first acoustic wave signal shows large signal changes (signal fluctuations), usually are the moments when the corresponding specimen just starts to be damaged or develops into another stage of damage, and the signal fluctuations are obvious and are significantly different from the surrounding acoustic wave signals. The moments of these signal fluctuations can be initially judged as the damage occurrence times of different creep damage stages.

[0058] Correspondingly, the damage occurrence time of each creep damage stage can be understood as the moment or the 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, and it is impossible to accurately judge the creep damage stage.

[0059] S300: Respectively obtain the microstructure data of the damage occurrence times corresponding to multiple second specimens during the second creep age forming process. Among them, the material of the second specimen is the same as that of the first specimen, and the process parameters of the second creep age forming and the first creep age forming are the same.

[0060] Since there are multiple moments for the damage occurrence time, multiple second creep age forming experiments need to be carried out, 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.

[0061] Taking the number of hours of the damage occurrence time as 3 as an example, they are t1, t2, and t3 respectively. Therefore, different second specimens are required for the second creep age forming experiments with the same process parameters. For example, the microstructure data of a second specimen at t1 during the second creep age forming process. Another second specimen has microstructure data at t2 during the second creep age forming process. Yet another second specimen has microstructure data at t3 during the second creep age forming process. Specifically, samples are taken from the second specimens respectively for microstructure observation to obtain the evolution law of the internal microstructure of the material under different creep damage times. The methods of sampling and microstructure observation are not specifically limited.

[0062] In the conventional experiments for obtaining the creep damage degree through the microstructure analysis of materials under different creep processes, it is necessary to continuously conduct creep age experiments with different processes to obtain specimens for microscopic observation, and it is impossible to accurately capture the time corresponding to the creep damage of the materials.

[0063] In this application, experiments are carried out in combination with the acoustic emission technology. The acoustic emission technology can monitor the acoustic wave signals of the specimens throughout the creep age process, and mark the time of creep damage by analyzing and recording the fluctuations of the acoustic signals. Based on this, formulating creep process plans with different creep durations will greatly improve the efficiency of the microstructure analysis of material creep damage and reduce the trial-and-error cost and analysis and testing cost.

[0064] S400: Based on the first acoustic wave signals corresponding to the first specimen at each of the damage occurrence times, and the microstructure data corresponding to each of the second specimens at each of the damage occurrence times, establish the mapping relationship between the first acoustic wave signals and the creep damage conditions to obtain the reference mapping relationship.

[0065] The structure of the second specimen is the same as or different from that of the first specimen. Since the material of the second specimen is the same as that of the first specimen, and the process parameters of the second creep age forming and the first creep age forming are the same. Therefore, at the same damage occurrence time, the microstructure data of the second specimen can be considered to be basically the same as that of the first specimen. In this way, the first acoustic wave signal of the first specimen is associated with the creep damage conditions, and a mapping relationship is established between the two to obtain the reference mapping relationship. The reference mapping relationship can be applied to the creep age forming process of the material corresponding to the first specimen.

[0066] S500: Carry out the third creep age forming on the workpiece under the condition of collecting the second acoustic wave signals corresponding to the acoustic emission, and adjust the process parameters of the third creep age forming based on the matching situation between the collected second acoustic wave signals and the reference mapping relationship during the forming process. Wherein, the material of the workpiece is the same as that of the first specimen.

[0067] In this step, the initial process parameters of the third creep age forming can be the same as or different from those of the first creep age forming. The structure of the workpiece can be the same as or different from that of the first specimen.

[0068] During the third creep age forming process, acoustic emission monitoring is carried out. The acoustic emission monitoring is used to guide the adjustment of the process parameters of the third creep age forming. For example, when the second acoustic wave signal collected is close to the acoustic wave signal when creep damage occurs in the reference mapping relationship, the process parameters are adjusted to avoid the occurrence of such creep damage.

[0069] In the above real-time monitoring method of creep damage based on acoustic emission, on the basis of detecting the first acoustic wave signal, a corresponding relationship is established by analyzing the fluctuation information of the acoustic wave signal and the creep damage occurrence time, and then the microscopic tissue evolution law under different damage occurrence times is determined. Finally, a corresponding relationship between the acoustic wave signal and the microscopic damage evolution is established and used to guide the adjustment of the creep age process. The internal microscopic tissue evolution of the material during the creep age process can be known through the change of the acoustic signal, so as to more conveniently and intuitively scientifically control the creep age process parameters, saving a large amount of research production time and production manufacturing costs.

[0070] In some embodiments, the step of collecting the first acoustic wave signal based on acoustic emission during the first creep age forming of the first specimen includes:

[0071] Collection points are set on the surface of the first specimen. The number of the collection points ≥ 1.

[0072] For example, sensors are placed on the surface of the first specimen. When the surface of the first specimen is large, the number of sensors is appropriately increased.

[0073] Under the conditions of the set acoustic emission collection parameters, the first acoustic wave signal based on acoustic emission at the collection points during the first creep age forming of the first specimen is collected. Wherein, the acoustic emission collection parameters include at least one of gain decibels, 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.

[0074] Under this condition, more types of relatively rich acoustic wave signal parameters are obtained, which is convenient for subsequent analysis based on the fluctuation of one or several of the acoustic wave signal parameters, and more accurately obtains the signal change situation of the first acoustic wave signal.

[0075] In some embodiments, the step of analyzing the corresponding relationship between the first acoustic wave signal and the creep time and obtaining the damage occurrence time corresponding to different creep damage stages of the first specimen includes:

[0076] Determine the creep damage stage of the first specimen according to the signal change of the first acoustic wave signal, and record the corresponding creep time as the damage occurrence time. The signal change includes at least one of frequency change, amplitude change, and energy change.

[0077] This method can accurately identify and determine information such as the moment when a large change in the signal change occurs and the duration, so as to accurately determine the creep damage stage.

[0078] In some embodiments, the step of respectively obtaining the microstructure data of each damage occurrence time corresponding to a plurality of second specimens during the second creep age forming process includes:

[0079] Perform second creep age forming on a plurality of second specimens respectively, and stop at the corresponding damage occurrence time for each.

[0080] Take samples from the second specimens after stopping the second creep age forming respectively, and determine the microstructure data therein.

[0081] In this embodiment, each second specimen is experimented at the damage occurrence moment corresponding to the second creep age forming, and then samples are taken to observe the microstructure data. The observation methods for microstructure observation include any one of OM, SEM, EBSD, TEM, XRD, 3D-XRD, and 3D-CT. That is, the damage occurrence time corresponding to different creep damage stages of the first specimen is used as a guide, and sampling analysis is carried out more precisely in each second creep age forming experiment, improving the accuracy of the results.

[0082] In some embodiments, the step of establishing the mapping relationship between the first acoustic wave signal and the creep damage situation based on the first acoustic wave signal corresponding to the first specimen at each damage occurrence time and the microstructure data corresponding to each second specimen at each damage occurrence time, and obtaining the reference mapping relationship includes:

[0083] Determine the corresponding creep damage situation according to the microstructure data corresponding to each second specimen at each damage occurrence time. The microstructure data includes at least one of the number of voids, void size, void distribution, precipitate size, precipitate distribution, precipitate number, dislocation density, dislocation distribution, recrystallization number, and grain orientation.

[0084] After associating the first acoustic wave signal of the first specimen at the same damage occurrence time and the creep damage situation of the second specimen at the same damage occurrence time respectively, gather them to obtain the reference mapping relationship.

[0085] Determine the creep damage situation of the second specimen based on one or several types of different microstructural data, and associate it with the first acoustic signal. Associate all different creep damage situations with their corresponding first acoustic signals 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 age forming.

[0086] In some embodiments, the step of adjusting the process parameters of the third creep age forming based on the matching situation between the second acoustic signal collected by acoustic emission during the forming process and the reference mapping relationship includes:

[0087] Collect the second acoustic signal of the workpiece based on acoustic emission in real time and match it with the reference mapping relationship.

[0088] If the second acoustic signal matches the first acoustic signal corresponding to the creep damage situation in the reference mapping relationship, adjust the process parameters of the third creep age forming.

[0089] In this way, the second acoustic signal is collected in real time, matched with the reference mapping relationship, and if it is consistent or close to the first acoustic signal corresponding to the creep damage situation, the process parameters of the third creep age forming are adjusted, thereby avoiding creep damage of the workpiece or reducing the probability of creep damage.

[0090] In some embodiments, before the step of performing the third creep age forming on the workpiece, it further includes:

[0091] Based on the reference mapping relationship, adjust the process parameters of the first creep age forming to obtain the initial process parameters of the third creep age forming.

[0092] In some cases, if it can be determined according to the reference mapping relationship that there is a risk of creep damage in the design process parameters of the third creep age forming, the process parameters can be adjusted in advance before the step of performing the third creep age forming, so that the number of adjustment times during the third creep age forming process is reduced, and the forming efficiency is improved.

[0093] Overall, the above-mentioned real-time monitoring method of creep damage based on acoustic emission has the following beneficial effects:

[0094] 1. Compared with the traditional creep damage time obtained by testing materials through different creep processes, acoustic emission technology can conduct full-process real-time monitoring of the internal acoustic signals of specimens during creep age forming. By analyzing the fluctuations of acoustic signals, the time when materials generate creep damage during creep age forming can be captured more accurately, improving the research efficiency of the creep damage process of materials and saving a large amount of research time and specimen production costs.

[0095] 2. To obtain the creep damage degree through the microstructure analysis of materials under different creep processes, it is necessary to continuously conduct creep aging experiments with different processes to obtain specimens for microscopic observation, and it is impossible to accurately capture the time corresponding to the creep damage of the materials. The acoustic emission technology can monitor the acoustic wave signals of the specimens throughout the creep aging process. By analyzing and recording the fluctuations of the acoustic signals, the time and degree of creep damage are marked. Based on this, formulating creep process plans with different creep durations will greatly improve the efficiency of the microstructure analysis of material creep damage and reduce the trial-and-error cost and analysis and testing cost.

[0096] 3. Compared with the traditional method of only monitoring the creep aging process of materials through acoustic emission technology, the method of the present invention, on the basis of detecting acoustic wave signals, establishes a corresponding relationship between the fluctuation information of the acoustic wave signals and the creep damage time, searches for the evolution law of the microstructure under different creep damage times, and finally establishes a corresponding relationship between the acoustic signal and the microscopic damage evolution and uses it to guide the adjustment of the creep aging process. It gives a scientific explanation of creep damage from the microscopic level, establishes a corresponding relationship between the creep damage microstructure and the acoustic signal, makes the creep damage microstructure "visual", and can know the internal microstructure evolution of the material during the creep aging process through the change of the acoustic signal, so as to more conveniently and intuitively scientifically control the creep aging process parameters.

[0097] This application also provides a real-time monitoring device for creep damage based on acoustic emission, see Figure 2 , including:

[0098] An acoustic wave signal acquisition mechanism 300, which is used to acquire the first acoustic wave signal based on the first acoustic emission during the first creep aging forming process of the first specimen, and the second acoustic wave signal based on the acoustic emission during the third creep aging forming process of the workpiece.

[0099] An acoustic emission analysis mechanism 500, which is communicatively connected to 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 different creep damage stages of the first specimen, and determine the matching situation between the second acoustic wave signal and the reference mapping relationship during the third creep aging forming process.

[0100] A microstructure observation mechanism, which is used to respectively obtain the microstructure data of each damage occurrence time corresponding to multiple second specimens during the second creep aging forming process. The material of the second specimen is the same as that of the first specimen, 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, 3D-CT mechanisms.

[0101] The creep mechanism 100 is used for performing the first creep age forming, the second creep age forming, and the third creep age forming. The creep mechanism 100 is further used for performing the third creep age forming on the workpiece in the case of collecting the second acoustic wave signal, and adjusting the process parameters of the third creep age forming according to the matching condition between the second acoustic wave signal and the reference mapping relationship. Wherein, the reference mapping relationship is a mapping relationship between the first acoustic wave signal and the creep damage condition established based on the first acoustic wave signal corresponding to each damage occurrence time of the first specimen and the microstructure data corresponding to each damage occurrence time of each second specimen.

[0102] The above-mentioned real-time monitoring device for creep damage based on acoustic emission has corresponding technical effects due to adopting the foregoing real-time monitoring method for creep damage based on acoustic emission, and thus will not be elaborated herein.

[0103] In some embodiments, the acoustic wave signal acquisition mechanism 300 includes a sensor 310 and an amplifier 320. The amplifier 320 is respectively communicatively connected to the sensor 310 and the acoustic emission analysis mechanism 500. The sensor 310 is used to be placed on the first specimen and the workpiece. The number of the sensors 310 is ≥1, and the temperature resistance range is -80°C to 220°C. The gain amplification range of the amplifier 320 is 20dB to 60dB.

[0104] Wherein, the size of the sensor 310 is selected according to the area where the specimen can be placed. For example, the sensor 310 and the amplifier 320 are connected through a signal line 400, and the amplifier 320 is connected to the acoustic emission analysis mechanism 500 through the signal line 400.

[0105] In some embodiments, the acoustic emission analysis mechanism 500 includes an acoustic emission acquisition card 510. The number of the acoustic emission acquisition cards 510 is ≥1, the operating temperature is -30°C to 70°C, and the bandwidth is 1kHz to 400kHz.

[0106] In some embodiments, in addition to including the acoustic emission acquisition card 510, the acoustic emission analysis mechanism 500 further includes 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 an analog signal into a data signal. The acoustic emission acquisition card 510 is connected to the computing mechanism 520 through a transmission line 600 to transmit data. The computing mechanism 520 analyzes the acoustic wave signal collected by the acoustic emission acquisition card 510.

[0107] The technical solution of the present application will be described below in conjunction with specific embodiments.

[0108] A real-time monitoring method for creep damage based on acoustic emission includes the following steps:

[0109] Q1: The surface of the first specimen is treated, and the first specimen is fixed on a creep machine. Two pairs of upper and lower extensometers are installed on the specimen, and an extensometer is installed on the extensometer to measure deformation. A sensor is fixed on the first specimen, and the sensor is connected to the specimen with a coupling agent, and the position of the sensor 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 through a transmission line. The acoustic emission analysis system includes an acoustic emission acquisition card, an AD converter, and a computer capable of running the acoustic emission analysis executable program.

[0110] Among them, the material of the first specimen is 7xxx series high-strength aluminum alloy with a thickness of 2 mm, and the specimen type is a plate specimen. The heat treatment state is over-aged state, and the surface is rough ground, fine ground, and mechanically polished.

[0111] The strain during the creep aging process is measured by a mechanical tensile and compressive extensometer. The creep aging process parameters are a creep temperature of 140 °C, a creep stress of 350 MPa, a heating rate of 5 °C / min, and a loading rate of 15 N / s.

[0112] The number of sensors is 2, and the size is , the temperature resistance range is -65 °C - 177 °C, and the detection frequency band is 50 kHz - 400 kHz.

[0113] The acoustic emission acquisition parameters are set as a gain of 40 dB, a sampling rate of 2000 kHz, a sampling length of 2000 points, a hit time of 2000 μs, and a peak definition time of 1000 μs.

[0114] Q2: Set the first creep aging process parameters on the creep mechanism, and turn on the acoustic wave signal acquisition mechanism and the acoustic emission analysis mechanism. Set the acoustic emission acquisition parameters, and at the same time start the creep machine, the acoustic wave signal acquisition mechanism, and the acoustic emission analysis mechanism to start the creep aging experiment of the first specimen.

[0115] Among them, the creep aging process parameters specifically include creep temperature, heating rate, creep holding time, load magnitude, and loading rate.

[0116] Among them, the acoustic emission acquisition parameters specifically include gain in decibels, sampling rate, sampling length, hit time, and peak definition time.

[0117] Q3: After the first creep aging is completed, open the furnace to cool down, tear off the high-temperature glue, remove the sensor on the first specimen, and unload the first specimen. Analyze the corresponding relationship between the acoustic wave signal and the creep time in the acoustic emission analysis software of the acoustic emission analysis mechanism, and obtain and record the starting time of creep damage and the change law of the acoustic wave signal during the creep damage process.

[0118] Among them, the acoustic wave signals include amplitude, cumulative amplitude, ring count, energy, number of impacts, cumulative number of impacts, etc.

[0119] Q4: According to the variation law of the acoustic wave signals during the creep damage process obtained in Q3, obtain the corresponding relationship between the damage occurrence time and the damage degree during the creep damage process, and based on this, formulate the creep aging process plan with different creep durations (from the start of the second creep aging forming to each damage occurrence time) in the second creep aging forming.

[0120] Q5: Prepare the corresponding number of samples according to the number of the process plans formulated in Q4, conduct creep aging experiments with different creep durations, and observe the microstructure of the deformation zones of the specimens for each creep process, so as to obtain the evolution law of the internal microstructure of the material under different creep damage times.

[0121] Among them, for the microstructure observation, the observation methods include OM, SEM, EBSD, TEM, XRD, 3D-XRD, 3D-CT.

[0122] Among them, for the microstructure observation, the observation contents include 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.

[0123] Q6: Set the corresponding relationship between the variation law of the acoustic wave signals during the creep damage process in Q3 and the microstructure evolution law in Q5, construct a mapping relationship diagram of acoustic wave signals - microstructure, and obtain the internal acoustic signal results of the material with different damage degrees, which are used to guide the formulation of creep aging process parameters.

[0124] In the above technical solutions of the present invention, the above are only the preferred embodiments of the present invention, and do not limit the protection scope of the present invention accordingly. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is 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 the 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; 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.

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 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.

5. 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.

6. The real-time monitoring method for creep damage based on acoustic emission according to any one of claims 1 to 5, 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.

7. A real-time monitoring device for creep damage based on acoustic emission, using the real-time monitoring method for creep damage based on acoustic emission according to any one of claims 1 to 6, 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, used for performing a first creep aging forming, a second creep aging forming and a third creep aging forming; the creep mechanism is also used for performing a third creep aging forming on the workpiece while collecting a second acoustic wave signal, and adjusting 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; 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.

8. The real-time monitoring device for creep damage based on acoustic emission according to claim 7, 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.

9. The real-time monitoring device for creep damage based on acoustic emission according to claim 7 or 8, 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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