Integrity monitoring device and method for small-size metal sample in high-pressure environment

Abstract

The invention discloses a device and a method for monitoring the integrity of a small-size metal sample in a high-pressure environment. An environment control system; the loading system comprises an electronic testing machine and a connecting rod, and the electronic testing machine loads a small-size metal sample installed in the high-pressure kettle in an electric insulation mode through the connecting rod to achieve stress or strain controlled loading; the electric signal measurement system comprises a constant current source, a current commutation device and a signal acquisition device. The constant current source applies a constant current to the small-size metal sample, the current reversing equipment switches the direction of the constant current at a preset frequency, and the signal acquisition equipment intermittently monitors voltage values at two ends of the small-size metal sample; and determining the integrity change of the small-size metal sample according to the change of the voltage value in the loading process. According to the invention, on-line monitoring of the integrity of the small-size metal sample is realized in a high-pressure environment.

Description

Technical Field

[0001] The present invention belongs to the field of high-end equipment material performance evaluation, and in particular relates to a device and method for monitoring the integrity of small-sized metal samples under high-pressure environments. Background Art

[0002] In some industrial fields, equipment is exposed to extremely harsh environments with high-pressure fluids for extended periods of time. Examples include the high-temperature, high-pressure water and gas environments of nuclear power plants, the low-temperature, high-pressure seawater environments of deep-sea equipment, and the high-pressure gaseous hydrogen environments of hydrogen transmission and storage facilities. When metal structural materials serve in such environments, they are extremely susceptible to the combined effects of multiple factors, including loads and corrosion, leading to gradual performance degradation and even failure. Therefore, both industry and academia have long prioritized laboratory research to reveal the patterns of material aging and failure, ensuring the structural integrity and safety of critical equipment during service.

[0003] In the relevant experimental process, how to accurately grasp the integrity of the experimental samples is a prerequisite for improving experimental efficiency and the reliability of conclusions. For large-sized metal samples, the deformation or failure of the samples can usually be directly monitored with the help of devices such as displacement extensometers or force sensors. However, for small-sized metal samples, due to their small deformation, low load-bearing capacity and limited damage area, it is difficult for existing sensors to effectively capture their state changes. At present, we can only rely on periodic suspension of the experiment, taking out the samples and conducting multi-scale inspections with the naked eye or microscope to determine whether there are cracks or fractures to confirm their integrity. Not only is the operation cumbersome and inefficient, but it also destroys the continuity of the experiment. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the present invention provides a device and method for monitoring the integrity of small-sized metal samples under high-pressure environments, thereby realizing online monitoring of the integrity of small-sized metal samples under high-pressure environments.

[0005] The present application provides an integrity monitoring device for small-sized metal samples in a high-pressure environment, an autoclave, which realizes high-pressure environment sealing through a sealing structure and is used to accommodate small-sized metal samples; Environmental control system, connected to the autoclave, used to regulate the environmental parameters of the autoclave; A loading system comprising an electronic testing machine and a connecting rod, wherein the electronic testing machine loads a small-sized metal sample installed in an electrically insulated manner in the autoclave through the connecting rod to achieve stress or strain controlled loading; The electrical signal measurement system includes a constant current source, a current commutation device, and a signal acquisition device; the constant current source applies a constant current to the small-sized metal sample, the current commutation device switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value at both ends of the small-sized metal sample; the integrity change of the small-sized metal sample is determined based on the change in the voltage value during the loading process.

[0006] In some embodiments, the signal acquisition device includes a multi-channel signal meter, a voltmeter and wires; the wires are respectively connected to the two ends of the small-sized metal sample; the multi-channel signal meter is used to synchronously record voltage signals, load displacement signals and environmental parameters.

[0007] In some embodiments, the frequency of switching the current direction of the current reversing device is 0.1-10 Hz.

[0008] In some embodiments, the loading system is further provided with a clamping device, and the small-sized metal sample is electrically insulated from the clamping device by an insulating member.

[0009] In some embodiments, the wire is welded to the small-sized metal sample.

[0010] In a second aspect, the present invention discloses a method for monitoring the integrity of a small-sized metal sample under a high-pressure environment. The integrity monitoring device for a small-sized metal sample under the high-pressure environment described above comprises: fixing the small-sized metal sample in an autoclave and closing the autoclave; Inject the medium through the environmental control system, adjust the environmental parameters to the preset range, and maintain the stability of the medium composition; A controlled load is applied to the small-sized metal sample through a loading system; a constant current is applied through a constant current source, and a current reversing device switches the current direction at a preset frequency, and a signal acquisition device intermittently monitors the voltage value across the small-sized metal sample; The integrity change of the small-sized metal sample is determined according to the change of the voltage value during the test.

[0011] In some embodiments, determining the integrity change of the small-sized metal sample according to the change in voltage value during the test includes: Record the initial voltage value and compare the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample is intact; During the test, the loading system performs voltage measurement and continuously collects real-time voltage values, which are compared with the initial voltage values; and each time the voltage value is measured, the loading system pauses loading; When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, the integrity of the small-size metal sample changes, and the corresponding loading conditions and environmental parameters are recorded.

[0012] In some embodiments, the frequency at which the current reversing device switches the direction of the current is determined according to the connection between the wire and the small-size metal sample, and the preset frequency is 0.1-10 Hz.

[0013] In some embodiments, the standard deviation threshold includes a first threshold and a second threshold: when the real-time voltage value deviates from the initial average value by more than the first threshold and not more than the second threshold, the small-size metal sample is partially broken; and when the real-time voltage value deviates from the initial average value by more than the second threshold, the small-size metal sample is completely broken.

[0014] In some embodiments, the first threshold is 3-5 times the standard deviation of the initial voltage value, and the second threshold is 10-100 times the standard deviation of the initial voltage value.

[0015] The present application provides a device and method for monitoring the integrity of a small-size metal sample in a high-pressure environment. By applying a constant current to the small-size metal sample in a high-pressure environment and using a current reversing device to switch the direction of the current at a preset frequency, and intermittently measuring the voltage value across the small-size metal sample by a signal acquisition device, the interference of contact resistance and changes in the dielectric environment on the measurement results can be effectively avoided. By comparing the changes in the voltage value during the loading process, it can be accurately determined whether the small-size metal sample has changed in integrity without destroying the continuity of the experiment, thereby online monitoring, reducing the frequent operations of traditional shutdown sampling inspection, improving the experimental efficiency, and ensuring the continuity and reliability of the data. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 A structural schematic diagram of the device for monitoring the integrity of a small-size metal sample in a high-pressure environment provided by the present application; Figure 2 A flowchart of the method for monitoring the integrity of a small-size metal sample in a high-pressure environment provided by the present application; Figure 3 Simulation results based on an alloy sheet sample with a length of 30 mm, a width of 2 mm, and a thickness of 0.2 mm.

[0017] Figure 4 With Figure 5 Test results based on an alloy sheet sample with a length of 30 mm, a width of 2 mm, and a thickness of 0.2 mm.

[0018] In the figure: 1. Autoclave; 2. Electronic testing machine; 3. Connecting rod; 4. Environmental control system; 5. High-pressure pump; 6. Back-pressure valve; 7. Constant current source; 8. Voltmeter; 9. Current reversing device; 10. Multi-channel signal instrument; 11. Processor; 12. Small-sized metal sample. DETAILED DESCRIPTION

[0019] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention, in conjunction with the accompanying drawings. It should be understood that the described embodiments are only some of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and in no way limits the present invention, its application, or use. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are intended to be protected by the present invention. Unless otherwise specified, the relative arrangement of components and steps, expressions, and numerical values ​​described in these embodiments do not limit the scope of the present invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to scale. Technologies, methods, and devices known to persons of ordinary skill in the relevant art may not be discussed in detail, but, where appropriate, such technologies, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely illustrative and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0020] The present application provides a device for monitoring the integrity of a small-sized metal sample 12 under a high-pressure environment, which realizes online monitoring of the integrity of the small-sized metal sample 12 under a high-pressure environment.

[0021] Specifically, such as Figure 1 FIG. 1 is a schematic diagram of the structure of the integrity monitoring device for a small-sized metal sample 12 under a high-pressure environment, comprising an autoclave 1, an environmental control system 4, a loading system, and an electrical signal measurement system. The high-pressure environment is sealed by a sealing structure, and the device is used to accommodate the small-sized metal sample 12. An environmental control system 4, connected to the autoclave 1, for regulating environmental parameters of the autoclave 1; A loading system, comprising an electronic testing machine 2 and a connecting rod 3, wherein the electronic testing machine 2 loads a small-sized metal sample 12 installed in an electrically insulated manner in the autoclave 1 through the connecting rod 3 to achieve stress or strain controlled loading; The electrical signal measurement system includes a constant current source 7, a current commutation device 9, and a signal acquisition device; the constant current source applies a constant current to the small-size metal sample 12, the current commutation device 9 switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value at both ends of the small-size metal sample 12; the integrity change of the small-size metal sample 12 is determined based on the change in the voltage value during the loading process.

[0022] It is worth noting that the small-sized metal sample 12 used may be referred to as the sample hereinafter; the small-sized metal sample 12 refers to a metal sample in which the load borne by the sample during loading is not significantly greater than the friction force of the loaded connecting rod 3, and the loading starting point cannot be determined by the traditional force value. Generally, it includes metal sheets or micro-rods, etc., and the force it bears is less than tens of Newtons. The integrity of the small-sized metal sample 12 refers to the ability of the sample to maintain its original structural state under loading and high-pressure environment. The change in integrity is that when the small-sized metal sample 12 does not show structural damage such as cracks or fractures during the entire experimental process, it is judged to be in an intact state; when the sample undergoes local crack extension or local fracture, but there is still a load-bearing area that is not completely separated, it is judged to be in a partially fractured state; when the sample as a whole is completely fractured or loses continuity and can no longer bear the load, it is judged to be in a completely fractured state.

[0023] The autoclave 1 is made of an alloy material with excellent corrosion resistance, preferably stainless steel or a nickel-based alloy. In actual experiments, the material selection and sealing structure can be determined based on the specific test medium, temperature, and pressure requirements. In actual applications, the autoclave can be designed according to the actual use purpose, and this is not specifically limited in this application.

[0024] To accommodate a variety of harsh operating conditions, including the high-temperature, high-pressure water environment of nuclear power plants, the low-temperature, high-pressure seawater environment of deep seas, and the high-pressure gaseous hydrogen environment of hydrogen transmission and storage, the autoclave 1 can be designed with a pressure rating of 30MPa to 100MPa, a temperature range of -50°C to 700°C, and can be expanded accordingly based on experimental requirements. The autoclave 1 is equipped with a medium inlet and outlet, a pressure detection port, and a temperature sensor port, which can communicate with the external environmental control system 4 to achieve fluid circulation, pressure regulation, and temperature control, ensuring the long-term stability of the medium composition and physical parameters within the autoclave. At the same time, the autoclave structure has undergone finite element strength verification and can withstand the internal pressure loads under the action of high-pressure fluids and ensure that no plastic deformation or seal failure occurs under multiple cyclic loading cycles, thereby providing a stable and repeatable high-pressure test environment for integrity monitoring of small-sized metal samples 12.

[0025] The environmental control system 4 is connected to the autoclave 1 and is used to control the environmental parameters of the autoclave 1, enabling it to simulate various test environments, including nuclear power plant high-temperature, high-pressure water environments, nuclear power plant high-temperature, high-pressure gas environments, deep-sea low-temperature, high-pressure seawater environments, and high-pressure hydrogen environments. The environmental control system 4 includes functional modules such as a high-pressure pump 5, a backpressure valve 6, and a heating jacket or heat exchanger. The medium can be a water-based solution or an inert gas, depending on experimental requirements. Specific control parameters include the solute concentration, dissolved gas content, pH value, conductivity, or the component ratio of the gas medium. The high-pressure pump 5 injects the test medium into the autoclave 1 and provides continuous pressure input. The backpressure valve 6 adjusts and maintains the target pressure within the autoclave to meet the load-corrosion coupled environment simulation requirements under specific operating conditions. A heating jacket or heat exchanger, located on the outer wall of the autoclave 1, heats or cools the medium, maintaining the test temperature within a set range, for example, from room temperature to 300°C, or simulating low-temperature environments.

[0026] When the test medium is a water-based solution, the environmental control system 4 adjusts the solution's solute concentration, dissolved gas content, pH value, and conductivity. When the test medium is a gas, the environmental control system 4 regulates the gas component ratio and maintains stability. During long-term loading tests, the environmental control system 4 dynamically adjusts the medium's composition and physical parameters and performs real-time monitoring, ensuring that the internal environment of the autoclave 1 remains within a preset range. This meets the experimental requirements for integrity monitoring of small-sized metal samples 12, while preventing fluctuations in the test environment from interfering with the integrity monitoring results, thereby improving the accuracy and comparability of experimental data.

[0027] The loading system includes an electronic testing machine 2 and a connecting rod 3. The electronic testing machine 2 loads a small-sized metal sample 12 installed in an electrically insulated manner within the autoclave 1 through the connecting rod 3, and is used to apply controlled stress or strain to the small-sized metal sample 12 under a high-voltage environment. The electronic testing machine 2 is disposed outside the autoclave 1, and its loading end is connected to the connecting rod 3. The connecting rod 3 passes through the autoclave lid of the autoclave 1 and extends into the autoclave, transmitting the loading force or displacement output by the electronic testing machine 2 to the small-sized metal sample 12. To avoid electrical signal interference, the loading system is also provided with a clamping device. The small-sized metal sample is electrically insulated from the clamping device by an insulating member. The insulating member between the connecting rod 3 and the small-sized metal sample 12 is electrically isolated from the autoclave 1 and the connecting rod 3, so that the current forms a circuit only through the sample, thereby ensuring the accuracy of the electrical signal measurement.

[0028] During the loading process, the electronic testing machine 2 controls the connecting rod 3 to apply constant strain rate loading, step loading, or cyclic loading to the small metal sample 12 along a preset loading path. Loading accuracy can reach micron-level displacement or Newton-level load control levels. The loading system and the electrical signal measurement system are independent of each other, and the electrical insulation design effectively prevents interference from the loading process on the electrical signal acquisition, thereby improving the reliability of subsequent integrity monitoring.

[0029] The electrical signal measurement system is used to monitor the integrity changes of the small-sized metal sample 12 in real time or intermittently during the loading process, and includes a constant current source 7, a current reversing device 9, and a signal acquisition device; the constant current source applies a constant current to the small-sized metal sample 12, the current reversing device 9 switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value at both ends of the small-sized metal sample 12; the integrity changes of the small-sized metal sample 12 are determined based on the changes in the voltage value during the loading process.

[0030] The signal acquisition device includes a multi-channel signal analyzer 10, a voltmeter 8, and wires. The wires connect the voltmeter 8 to the two ends of the small metal sample 12 along its length. The multi-channel signal analyzer is used to simultaneously record voltage values, load displacement signals, and environmental parameters. A constant current source 7 provides a stable, constant DC current that flows through the small metal sample 12 via the wires. The voltmeter 8 measures the voltage values ​​and slight changes across the metal sample, transmitting the voltage values ​​to the multi-channel signal analyzer 10 and recording and processing by the processor 11. The current switching device 9 can switch the current direction at a frequency of 0.1 to 10 Hz to eliminate the effects of contact resistance heating on voltage signal stability, ensuring more accurate and reliable measurement results. In this application, the current switching device 9 is based on the influence of the connection between the wire and the small metal sample 12, including factors such as material type and connection method. In practical applications, a frequency of approximately 1 Hz is generally selected to prevent contact resistance heating from interfering with local voltage changes. The voltmeter 8 can be a nanovoltmeter to monitor subtle voltage changes when the sample is partially broken.

[0031] In actual operation, Figure 2 As shown, the following integrity monitoring methods are used: Step S1, fixing the small-sized metal sample 12 in the autoclave 1 and closing the autoclave 1; Step S2: injecting medium through the environmental control system 4, adjusting environmental parameters to a preset range, and maintaining the stability of the medium components; Step S3: applying a controlled load to the small-sized metal sample 12 through the loading system; applying a constant current through the constant current source 7 and switching the current direction at a preset frequency of the current commutation device; and intermittently monitoring the voltage value across the small-sized metal sample 12 by the signal acquisition device; Step S4: determining the integrity change of the small-sized metal sample 12 according to the change of the voltage value during the test process.

[0032] To ensure the sensitivity of electrical signal detection, the sample is mounted within autoclave 1 using electrical insulation, ensuring that current forms a circuit only through the sample and does not flow through the autoclave 1 or the metal components of the loading system. The loading system applies a controlled load to the sample, and the signal acquisition device pauses loading during each voltage measurement to prevent noise from the test process from interfering with electrical signal acquisition. During the test, the loading system applies stress and collects voltage values.

[0033] Determining the integrity change of the small-sized metal sample 12 according to the change of the voltage value during the test includes: Step S41, recording the initial voltage value, and comparing the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample 12 is intact; Step S42: During the test, the system performs voltage measurement and continuously collects real-time voltage values, and compares them with initial voltage values; and each time a voltage value is measured, the loading system pauses loading; Step S43: When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, it is determined that the integrity of the small-sized metal sample 12 has changed, and the corresponding loading conditions and environmental parameters are recorded.

[0034] Before the test begins, the initial voltage value of the intact small-scale metal sample 12 is recorded, and the distribution characteristics of the initial voltage value, including the mean and standard deviation, are statistically obtained. The initial voltage value represents the voltage signal when the small-scale metal sample 12 is intact. During the loading test, the signal acquisition device intermittently measures the voltage value at both ends of the sample and compares it with the distribution characteristics of the initial voltage value. If the voltage value deviates significantly from the initial value for a continuous period of time, it is considered that the sample integrity has changed.

[0035] During the test, the loading system applies stress or strain according to the preset loading path, and the electrical signal measurement system continuously collects the real-time voltage value at both ends of the small-sized metal sample 12. Each time the real-time voltage value is measured, the loading system pauses loading to prevent mechanical noise introduced by loading from interfering with the voltage signal measurement. The real-time voltage value is compared with the initial voltage value to determine the integrity status of the sample. When the real-time voltage value deviates from the average value, its integrity has changed, and the greater the degree of deviation, the higher the degree of damage. The standard deviation threshold includes a first threshold and a second threshold. When the amplitude of the real-time voltage value deviating from the initial average value exceeds the first threshold and is not greater than the second threshold, it is determined that the small-sized metal sample 12 has partially broken; when the amplitude of the real-time voltage value deviating from the initial average value exceeds the second threshold, it is determined that the small-sized metal sample 12 has completely broken. The first threshold is 3 to 5 times the standard deviation of the initial voltage signal, and the second threshold is 10 to 100 times the standard deviation of the initial voltage signal. Through the standard deviation threshold judgment standard, it is possible to sensitively distinguish whether the small-sized metal sample 12 is in an intact state, a partially broken state, or a completely broken state, and record it in combination with the loading conditions and environmental parameters at the time, so as to accurately capture the entire process of the change in the structural integrity of the sample.

[0036] The standard deviation threshold value of each time is affected by the material and size of the sample and the conductivity of the environmental medium in the autoclave. It should be noted that the conductivity of the environmental medium has a certain influence on the degree of signal change. When the medium has good conductivity, even if cracks or gaps appear in the sample, the medium may still conduct the crack gaps, making the voltage signal change smaller; and when the medium has poor conductivity or is non-conductive, once the sample cracks, the circuit is blocked and the voltage signal changes more significantly. Therefore, the present invention can judge the integrity state of the small-sized metal sample 12 in combination with the degree of deviation of the voltage signal, and further distinguish whether the sample is in a complete, partially broken or completely broken state in combination with the deviation range, thereby realizing sensitive monitoring of sample integrity under high-pressure environment.

[0037] Figure 3 To obtain these results using finite element simulation, a 30mm long, 2mm wide, and 0.2mm thick 316 stainless steel alloy sample was placed in water. A constant current of 0.1A was applied to both ends of the sample along its length. A crack was introduced to one side of the sample's center width and through its thickness. The crack width was 0.1mm, and the depth ranged from 0 to 2mm, with a depth of 0mm corresponding to no crack and a depth of 2mm corresponding to a complete fracture. The voltage drop across the sample was calculated. The simulation results show that the voltage signal first rises slowly and then sharply as the crack depth increases. This indicates that when the sample is partially fractured, the voltage signal increases slightly compared to the intact sample, but the magnitude is limited. However, when the sample is completely fractured, the voltage signal increases by several orders of magnitude.

[0038] The same alloy samples were used for testing, such as Figure 4 As shown, the voltage signal fluctuates as the experiment progresses. The dashed line indicates deviations of the initial signal from the mean value by 5 standard deviations. The signal does not deviate significantly from days 0 to 19, corresponding to an intact sample. However, the signal deviates significantly on day 24, indicating a partial fracture of the sample. After the experiment was completed and the sample was removed, this was confirmed to be a partial fracture. Figure 5 This is a schematic diagram of voltage recording from another experiment. Dashed lines indicate deviations of the initial signal from the mean value by 5 standard deviations. The inset is a zoomed-in view. The voltage values ​​did not deviate significantly from day 0 to day 2, corresponding to an intact sample. On day 3, the voltage values ​​deviated significantly, increasing by more than two orders of magnitude compared to the initial value, indicating a complete fracture of the sample. After the experiment was completed and the sample was removed, complete fracture was confirmed.

[0039] The present invention can realize sensitive and reliable online monitoring of the integrity of small-sized metal samples 12 under high-voltage environment. By recording the initial voltage value of the sample in the intact state, and continuously collecting the real-time voltage value and comparing it with the initial value during the test, it is possible to capture the slight changes in the structural state of the sample in a timely manner. The loading system suspends loading during voltage measurement, effectively avoiding the noise interference introduced by the loading process, thereby ensuring the stability and accuracy of electrical signal acquisition. By setting the standard deviation threshold judgment standard, it is possible to distinguish between the three states of integrity, partial fracture and complete fracture of the sample, and the degree of deviation can quantitatively reflect the degree of damage development. Compared with the traditional method that relies on periodic shutdown inspections, this solution can obtain continuous and complete status data without interrupting the experiment, greatly improving the experimental efficiency.

[0040] The above are only some embodiments of the present invention. For those skilled in the art, several modifications and improvements can be made without departing from the inventive concept of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. An integrity monitoring device for small-sized metal samples under high pressure, characterized in that: include: Autoclave, which is sealed in a high-pressure environment through a sealing structure and is used to accommodate small-sized metal samples; Environmental control system, connected to the autoclave, used to regulate the environmental parameters of the autoclave; A loading system comprising an electronic testing machine and a connecting rod, wherein the electronic testing machine loads a small-sized metal sample installed in an electrically insulated manner in the autoclave through the connecting rod to achieve stress or strain controlled loading; An electrical signal measurement system includes a constant current source, a current commutation device, and a signal acquisition device; the constant current source applies a constant current to the small-sized metal sample, the current commutation device switches the direction of the constant current at a preset frequency, and the signal acquisition device intermittently monitors the voltage value across the small-sized metal sample; The integrity change of the small-sized metal sample is determined according to the change of the voltage value during the loading process.

2. The integrity monitoring device for small-sized metal samples under high pressure environment according to claim 1, characterized in that: The signal acquisition equipment includes a multi-channel signal meter, a voltmeter and wires; the wires are respectively connected to the two ends of the small-sized metal sample in the length direction and the voltmeter; the multi-channel signal meter is used to synchronously record voltage signals, load displacement signals and environmental parameters.

3. The integrity monitoring device for small-sized metal samples under high pressure environment according to claim 1, characterized in that: The frequency of switching the current direction of the current reversing device is 0.1~10Hz.

4. The device for monitoring the integrity of small-sized metal samples under high pressure environment according to claim 3, characterized in that: The loading system is further provided with a clamping device, and the small-sized metal sample is electrically insulated from the clamping device via an insulating member.

5. The device for monitoring the integrity of small-sized metal samples under high pressure environment according to claim 2, characterized in that: The wire is welded to the small-sized metal sample.

6. A method for monitoring the integrity of small-sized metal samples under high pressure, characterized in that: The integrity monitoring device for a small-sized metal sample under a high-pressure environment as described in claims 1 to 5 comprises: fixing the small-sized metal sample in an autoclave and closing the autoclave; Inject the medium through the environmental control system, adjust the environmental parameters to the preset range, and maintain the stability of the medium composition; A controlled load is applied to the small-sized metal sample through a loading system; a constant current is applied through a constant current source, and a current reversing device switches the current direction at a preset frequency, and a signal acquisition device intermittently monitors the voltage value across the small-sized metal sample; The integrity change of the small-sized metal sample is determined according to the change of the voltage value during the test.

7. The method for monitoring the integrity of a small-sized metal sample under a high-pressure environment according to claim 6, characterized in that: Determining the integrity change of the small-sized metal sample according to the change of the voltage value during the test, including: Record the initial voltage value and compare the real-time voltage value with the initial voltage value; the initial voltage value is the voltage signal when the small-sized metal sample is intact; During the test, the loading system performs voltage measurement and continuously collects real-time voltage values, which are compared with the initial voltage values; and each time the voltage value is measured, the loading system pauses loading; When the real-time voltage value deviates from the average value and exceeds the standard deviation threshold, the integrity of the small-size metal sample changes, and the corresponding loading conditions and environmental parameters are recorded.

8. The method for monitoring the integrity of small-sized metal samples under high pressure environment according to claim 7, characterized in that: The frequency at which the current reversing device switches the current direction is determined according to the connection point between the wire and the small-sized metal sample, and the preset frequency is 0.1~10Hz.

9. The method for monitoring the integrity of small-sized metal samples under high pressure environment according to claim 7, characterized in that: The standard deviation threshold includes a first threshold and a second threshold: when the real-time voltage value deviates from the initial average value by more than the first threshold and is not greater than the second threshold, the small-sized metal sample partially breaks; when the real-time voltage value deviates from the initial average value by more than the second threshold, the small-sized metal sample completely breaks.

10. The method for monitoring the integrity of a small-sized metal sample under a high-pressure environment according to claim 9, characterized in that: The first threshold is 3 to 5 times the standard deviation of the initial voltage value, and the second threshold is 10 to 100 times the standard deviation of the initial voltage value.

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