Stress corrosion microcell in-situ electrochemical testing device and testing method thereof

Abstract

The invention discloses a stress corrosion micro-area in-situ electrochemical testing device which comprises a stress loading device, and the device comprises a body, an electrode assembly, a first stress adjusting assembly, a second stress adjusting assembly, a first displacement sensor and a second displacement sensor; the first stress adjusting assembly and the second stress adjusting assembly are respectively applied to two ends of the sample in a spring type loading mode; probes of the first displacement sensor and the second displacement sensor abut against the first stress adjusting assembly and the second stress adjusting assembly respectively. When in-situ testing operation of the stress corrosion micro-area is carried out, a sample is immersed in a corrosion solution contained in the body after a certain stress is applied to the sample, and in-situ electrochemical testing is carried out through the electrode assembly. The testing device disclosed by the invention not only can realize synchronization of stress and electrochemical testing, but also can provide accurate stress loading and displacement monitoring, and can meet strict requirements on stress corrosion performance testing in material scientific research and engineering application.

Description

Technical Field

[0001] The invention relates to the technical field of electrochemistry, and in particular to a stress corrosion micro-area in-situ electrochemical testing device and a testing method thereof. Background Art

[0002] In the field of materials science and engineering, stress corrosion is a form of material failure caused by the combined effect of stress and corrosive environment, which poses a serious threat to the safety and reliability of key industrial fields. Especially in the marine environment, the synergistic effect of high humidity and strong corrosive conditions and stress loads intensifies the test of material safety performance. With the continuous deepening of marine development, the demand for new marine materials with excellent stress corrosion resistance is increasing. Therefore, it is crucial to deeply study the stress corrosion sensitivity of materials under different conditions. The formation and development of stress corrosion cracks in alloy materials is a complex multi-factor process, which usually occurs at the micro-nano level. Traditional electrochemical technology can only test the overall corrosion behavior and it is difficult to accurately and comprehensively analyze the stress corrosion mechanism. Although micro-area electrochemical testing technologies such as scanning electrochemical microscopy technology, scanning vibration electrode technology and local electrochemical impedance spectroscopy technology can monitor the local electrochemical behavior of materials with constant load while keeping the original position of the material and the real environmental conditions unchanged, there is currently a lack of a device and method that can realize in-situ electrochemical testing of stress corrosion micro-areas.

[0003] In the prior art, the Chinese patent "A Constant Load Tensile Test Device" (CN 204116145 U) proposes a stress ring type constant load loading device, which sets the force for the metal sample loading experiment through the stress ring load detector, the stress ring loading probe and the clamp adjusting the second bolt. However, the device has many parts, which increases the manufacturing cost and installation complexity, and the difference in tightening degree and the stress ring processing accuracy may cause fluctuations in stress control accuracy, affecting the experimental results. In addition, the device is designed to be placed vertically and cannot be used in conjunction with an ultra-micro probe scanning device, and the mechanical loading accuracy is limited, so only simple macroscopic electrochemical tests can be performed, and micro-area tests cannot be performed. Another Chinese patent "A Multifunctional Aluminum Alloy Stress Tensile Test Equipment" (CN 214503167 U) discloses a tensile hydraulic cylinder type load loading device, which controls the tensile stress and loading rate of the aluminum alloy plate by controlling the hydraulic pump output pressure and the hydraulic cylinder extension speed through a control switch. However, in the NaCl solution simulating the marine environment, the liquid may penetrate into the joints of the various components of the device or the electrical connections, causing short circuit faults. Long-term use of the solution will also affect the mechanical transmission part, destroy the normal shock-absorbing mechanism of the shock-absorbing arc plate, and endanger the structural integrity and mechanical stability of the device. This device is suitable for simple tensile fatigue test experiments on alloy materials, but it cannot meet the basic conditions of alloy stress corrosion testing. The main disadvantages of the existing technology are that the stress loading device cannot accurately calculate the stress size, the stress loading accuracy is insufficient, and it is difficult to simulate certain actual working conditions such as the marine environment; most of the designed devices are large in size, and cannot be adapted to the scanning probe device when conducting micro-area electrochemical experiments on materials, and it is more troublesome to conduct micro-area tests. Summary of the invention

[0004] In view of the above shortcomings of the prior art, the present invention provides a stress corrosion micro-area in-situ electrochemical testing device to solve the technical problems existing in the traditional testing methods, such as inaccurate stress application, difficulty in simulating actual working conditions in the testing environment, complex operation and low efficiency. The present invention realizes the simultaneous implementation of stress loading and electrochemical testing through an integrated design concept, improves the accuracy and efficiency of the test, reduces the complexity of the operation, and at the same time, by simulating different corrosion environments, provides flexibility for studying the stress corrosion performance of materials in different environments, thereby promoting technological progress in the field of materials science.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A stress corrosion micro-area in-situ electrochemical testing device, the testing device comprising a stress loading device, the stress loading device comprising:

[0007] A body, wherein the body contains a sample to be tested;

[0008] An electrode assembly, the electrode assembly being mounted in the body, the electrode assembly comprising a counter electrode and a reference electrode;

[0009] a first stress adjustment component, the first stress adjustment component being applied to one end of the specimen by a spring-type loading method;

[0010] a second stress regulating assembly, the second stress regulating assembly being applied to the other end of the specimen by a spring-type loading method;

[0011] a first displacement sensor, wherein a probe of the first displacement sensor abuts against the first stress adjustment component; and

[0012] a second displacement sensor, wherein a probe of the second displacement sensor abuts against the second stress adjustment component;

[0013] When the testing device performs stress corrosion micro-area in-situ testing, the sample is immersed in a corrosion solution contained in the body after a certain stress is applied, and an in-situ electrochemical test is performed through the electrode assembly.

[0014] The stress corrosion micro-area in-situ electrochemical testing device of the present invention realizes the accurate evaluation of the stress corrosion performance of the material in the actual corrosive medium by integrating stress loading and in-situ electrochemical testing functions. One of its core points is the cleverly designed stress loading device, which has a simple structure and is easy to operate, and can conveniently simulate the influence of different stress magnitudes and constant stress on the stress corrosion performance of the material in a specific environment (such as a marine environment). In order to accurately apply stress, the device is designed with two sets of stress adjustment components, which correspond to the two ends of the sample respectively, and adopt a spring-type loading mechanism to ensure the accuracy of stress application. In addition, the device is equipped with two displacement sensors, which correspond to two stress adjustment components respectively. Their probes are in contact with the components, and the displacement changes during the stress loading process are monitored and fed back in real time, thereby ensuring the accuracy and stability of stress application. When performing stress corrosion testing, the sample is immersed in a body filled with corrosive medium after being subjected to a predetermined stress, and an in-situ electrochemical test is performed using a built-in electrode assembly, realizing the material performance evaluation in a simulated actual working environment. This integrated testing solution not only improves the efficiency and accuracy of the test, but also reduces the transfer of samples between different testing links by simultaneously performing stress loading and electrochemical testing in the same device, reduces operational complexity, and enhances data reliability and repeatability, providing an innovative and efficient testing method for materials science research and engineering applications.

[0015] As a preferred technical solution, the body includes an open steel base and a plastic base; the plastic base is placed inside the steel base. The body of the present invention provides a sturdy and corrosion-resistant test platform. The open design facilitates the placement and removal of samples. At the same time, the use of the plastic base can reduce the corrosion effect of the corrosive medium on the entire device, thereby improving the durability and service life of the device. In addition, the overall size of the device is small, and it can be used with an ultra-micro probe to scan the sample area to be tested for micro-area electrochemical testing.

[0016] As a preferred technical solution, the first stress adjustment component includes a first pin hole bolt, a first high-elasticity compression spring and a first nut; one end of the first pin hole bolt is provided with a pin hole and extends into the body through the side wall of the body, and the first pin hole bolt is fastened to one end of the sample by a first pin matched with the pin hole, the first high-elasticity compression spring is arranged on the surface of the first pin hole bolt outside the side wall of the body, and the other end of the first pin hole bolt is rotatably connected to the first nut. The first stress adjustment component of the present invention controls the spring compression amount on the first pin hole bolt by adjusting the first nut, thereby accurately applying stress to the sample and realizing accurate adjustment and control of stress.

[0017] As a preferred technical solution, the second stress adjustment component includes a second pin hole bolt, a second high elastic compression spring and a second nut; the second stress adjustment component and the first stress adjustment component are symmetrically arranged at the two side wall positions of the body; one end of the second pin hole bolt is provided with a pin hole and extends through the side wall of the body into the body, and the second pin hole bolt is fastened to the other end of the sample by a second pin that cooperates with the pin hole, and the second high elastic compression spring is arranged on the surface of the second pin hole bolt outside the side wall of the body, and the other end of the second pin hole bolt is rotatably connected to the second nut. The second stress adjustment component of the present invention controls the spring compression amount on the second pin hole bolt by adjusting the second nut, thereby accurately applying stress to the sample and realizing accurate adjustment and control of stress. The symmetrical arrangement of the second stress adjustment component of the present invention and the first stress adjustment component ensures that the forces at both ends of the sample are balanced, avoids test deviations caused by uneven stress application, and improves the accuracy and reliability of the test results.

[0018] As a preferred technical solution, the first displacement sensor is fixed on the side wall of the body and arranged in parallel with the first pin hole bolt, and the probe of the first displacement sensor abuts against the first nut; the second displacement sensor is fixed on the side wall of the body and arranged in parallel with the second pin hole bolt, and the probe of the second displacement sensor abuts against the second nut. The displacement sensor of the present invention can monitor the displacement change during stress loading in real time, accurately measure the displacement of the nut through the displacement sensor, and then calculate the stress applied to the sample, thereby ensuring the accuracy and stability of stress application and providing accurate data support for the experiment.

[0019] As a preferred technical solution, the test device also includes a three-dimensional positioning device and a probe moving console; the probe working electrode of the probe moving console is arranged close to the sample surface, the output end of the three-dimensional positioning device is electrically connected to the probe moving console to control the precise movement of the probe working electrode on the sample surface, and the input end of the three-dimensional positioning device is electrically connected to a computer. The present invention can realize precise control of the position of the probe working electrode through the three-dimensional positioning device and the probe moving console, so that the probe can be accurately positioned to a specific area on the sample surface for electrochemical testing, thereby improving the accuracy and repeatability of the test. Through the computer control of the three-dimensional positioning device, the operator can conveniently perform remote operation and programmed control, thereby enhancing the flexibility and automation of the test process.

[0020] As a preferred technical solution, the test device also includes an electrochemical workstation; the output end of the electrochemical workstation is electrically connected to the probe working electrode, the counter electrode and the reference electrode, and the input end of the electrochemical workstation is electrically connected to a computer. The present invention uses the probe working electrode as a microelectrode to form a three-electrode electrochemical test system with the counter electrode and the reference electrode, which satisfies the stress corrosion micro-area electrochemical test of the sample under high-precision mechanical loading.

[0021] As a preferred technical solution, the test device further includes a first display and a second display; the first display and the second display are electrically connected to the first displacement sensor and the second displacement sensor, respectively. The test device of the present invention can monitor the stress loading state and displacement change in real time through the display to ensure accurate control and adjustment of experimental conditions. The setting of the display improves the intuitiveness and interactivity of the experiment, allowing the operator to quickly respond to any changes in the experimental process, adjust the experimental parameters in time, and ensure the smooth progress of the experiment.

[0022] As a preferred technical solution, the testing device further comprises a computer; the computer is electrically connected to the three-dimensional positioning device and the electrochemical workstation.

[0023] Another aspect of the present invention is to provide a stress corrosion micro-area in-situ electrochemical testing method, wherein the testing method uses the stress corrosion micro-area in-situ electrochemical testing device as described above to perform stress corrosion micro-area in-situ electrochemical testing operations on a sample, and specifically comprises the following steps:

[0024] S1: Prepare the sample: place the sample to be tested inside the body of the stress loading device, and ensure that both ends of the sample are connected to the first stress adjustment component and the second stress adjustment component respectively and are ready;

[0025] S2 applies stress: by adjusting the first stress adjustment component and the second stress adjustment component, a predetermined stress is applied to both ends of the sample by a spring loading method, and at the same time, the first displacement sensor and the second displacement sensor are used to monitor the displacement change during the stress loading process;

[0026] S3 immersion of the sample: After a certain stress is applied to the sample, the sample is immersed in the corrosion solution contained in the body to prepare for electrochemical testing;

[0027] S4 positioning probe: Use the three-dimensional positioning device and the probe moving console to accurately position the probe working electrode to the predetermined test area on the sample surface;

[0028] S5 electrochemical test: In-situ electrochemical test is performed through the electrode assembly. A specific voltage or current is applied to the probe working electrode using an electrochemical workstation, and a surface scanning test is performed on the sample surface to evaluate the stress corrosion performance of the sample.

[0029] S6 controls probe movement: During the electrochemical test, the position of the probe working electrode is adjusted as needed. The probe movement console controls the precise movement of the probe working electrode on the sample surface to achieve testing of different areas of the sample.

[0030] S7 Data Collection and Analysis: The electrochemical test data is collected using an electrochemical workstation and analyzed using a computer connected to the test device and related software to determine the stress corrosion characteristics of the specimen.

[0031] Beneficial effects of the present invention:

[0032] The stress corrosion micro-area in-situ electrochemical testing device of the present invention provides a stress loading device with simple structure, high cost-effectiveness and easy operation through its innovative technical solution. The device can accurately measure the stress applied to the material sample and facilitate in-situ micro-area testing. Compared with the stress loading method that relies on complex mechanical structures or high-precision electronic equipment, the spring-type loading device adopted by the present invention has a simpler structure, reduces manufacturing costs, and simplifies the operation process. The applied stress is calculated by the ratio of the length of the spring compression to the cross-sectional area of ​​the sample, and an FCD displacement sensor is equipped to improve the accuracy of stress loading. In addition, the device can easily adapt to material samples of different types and sizes by replacing springs with different stiffness coefficients or adjusting the specifications and dimensions of components to meet diverse experimental conditions. In particular, in corrosive media such as simulated marine environments, the device shows extremely high adaptability and convenience, and will not have a critical impact on the experimental results due to the influence of corrosive media. The open container design of the device and the built-in electrode fixing platform make it simple to connect the corrosion test device and the measured area of ​​the sample through electrodes, and the micro-area in-situ test can be realized with the ultra-micro electrode scanning platform. The present invention not only realizes the performance evaluation of the material in a simulated actual working environment, but also realizes the real-time monitoring of the stress corrosion process, thereby enhancing the accuracy and repeatability of the test data, while maintaining the simplicity and safety of the experimental operation.

[0033] In general, the stress corrosion micro-area in-situ electrochemical testing device and its testing method of the present invention have excellent testing accuracy and convenient operation, and provide an efficient and reliable material performance evaluation tool that meets the strict requirements for stress corrosion performance testing in material science research and engineering applications. Through this integrated testing solution, the design and application of new materials can be effectively guided, providing strong support for technological progress in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the overall structure of the stress corrosion micro-area in-situ electrochemical testing device of the present invention.

[0035] Figure 2 It is a schematic diagram of the three-dimensional structure of the stress loading device of the present invention.

[0036] Figure 3 It is a top view of the stress loading device of the present invention.

[0037] Figure 4 It is a front view of the first pin hole bolt of the present invention.

[0038] Figure 5 It is a schematic diagram of the structure of the sample to be tested of the present invention.

[0039] Figure 6This is a physical picture of the stress loading device of the present invention.

[0040] Figure 7 This is a schematic diagram of the probe working electrode of the present invention performing electrochemical testing on a sample surface under stress.

[0041] Figure 8 This is a graph showing the changes in pH on the sample surface measured by the probe working electrode of the present invention.

[0042] Among them, there are a computer 1, a three-dimensional positioning device 2, a stress loading device 3, a probe moving console 4, an electrochemical workstation 5, a first display 6, a second display 7, a first pin 8, a plastic base 9, a steel base 10, a first displacement sensor 11, a counter electrode 12, a second displacement sensor 13, a reference electrode 14, a first nut 15, a first high-elasticity compression spring 16, a sample 17, a second pin 18, a second high-elasticity compression spring 19, a second nut 20, a first pin hole bolt 21, a second pin hole bolt 22, and a probe working electrode 401. DETAILED DESCRIPTION

[0043] The following description is used to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are only examples, and those skilled in the art may think of other obvious variations.

[0044] Example 1

[0045] like Figures 1 to 7 As shown, the stress corrosion micro-area in-situ electrochemical testing device of this embodiment includes a computer 1, a three-dimensional positioning device 2, a stress loading device 3, a probe moving console 4, an electrochemical workstation 5, a first display 6 and a second display 7; the stress loading device 3 includes a body, an electrode assembly, a first stress adjustment assembly, a second stress adjustment assembly, a first displacement sensor 11 and a second displacement sensor 13; the body contains a sample 17 to be tested; the electrode assembly is installed in the body, and the electrode assembly includes a counter electrode 12 and a reference electrode 14; the first stress adjustment assembly is applied to one end of the sample 17 by a spring-type loading method; the second stress adjustment assembly is applied to the other end of the sample 17 by a spring-type loading method; the probe of the first displacement sensor 11 is in contact with the first stress adjustment assembly; the probe of the second displacement sensor 13 is in contact with the second stress adjustment assembly; wherein, when the testing device performs a stress corrosion micro-area in-situ testing operation, the sample 17 is applied with a certain stress and then immersed in the corrosion solution contained in the body, and an in-situ electrochemical test is performed through the electrode assembly.

[0046] In at least one embodiment, the main body includes an open steel base 10 and a plastic base 9; the plastic base 9 is placed in the steel base 10. In order to meet the purpose of stress corrosion performance testing, a platform for fixing the counter electrode 12 and the reference electrode 14 is provided above the plastic base 9, and the counter electrode 12 and the reference electrode 14 are placed in the holes on the platform and locked by rubber rings. Above the sample 17, the probe working electrode 401 is used as a microelectrode to implement the electrochemical test of the stress corrosion micro-area of ​​the sample 17. The probe working electrode 401, the reference electrode 14 and the counter electrode 12 form a three-electrode system, and then the corrosion detection equipment is connected. Without changing the working conditions and positional relationship of the material and with high-precision mechanical loading, the in-situ test of the stress corrosion micro-area of ​​the sample 17 can be carried out.

[0047] In at least one embodiment, the first stress adjustment component includes a first pin hole bolt 21, a first high-elasticity compression spring 16 and a first nut 15; one end of the first pin hole bolt 21 is provided with a pin hole and extends through the side wall of the main body into the main body, and the first pin hole bolt 21 is fastened to one end of the sample 17 by a first pin 8 that cooperates with the pin hole, and the first high-elasticity compression spring 16 is arranged on the surface of the first pin hole bolt 21 outside the side wall of the main body, and the other end of the first pin hole bolt 21 is rotatably connected to the first nut 15. The second stress adjustment component includes a second pin hole bolt 22, a second high-elasticity compression spring 19 and a second nut 20; the second stress adjustment component and the first stress adjustment component are symmetrically arranged on the two side walls of the main body; one end of the second pin hole bolt 22 is provided with a pin hole and extends through the side wall of the main body into the main body, and the second pin hole bolt 22 is fastened to the other end of the sample 17 by a second pin 18 that cooperates with the pin hole. The second high-elasticity compression spring 19 is arranged on the surface of the second pin hole bolt 22 outside the side wall of the main body, and the other end of the second pin hole bolt 22 is rotatably connected to the second nut 20.

[0048] In at least one embodiment, the first displacement sensor 11 is fixed on the side wall of the body and arranged in parallel with the first pin hole bolt 21, and the probe of the first displacement sensor 11 abuts against the first nut 15; the second displacement sensor 13 is fixed on the side wall of the body and arranged in parallel with the second pin hole bolt 22, and the probe of the second displacement sensor 13 abuts against the second nut 20. The first display 6 and the second display 7 are electrically connected to the first displacement sensor 11 and the second displacement sensor 13, respectively. The method of providing stress loading to sample 17 is to further tighten the nuts on both sides with an Allen wrench to compress the high-elasticity compression spring; in order to accurately calculate the stress value, a precision micro-displacement sensor is used to measure the compression length. The working principle of this sensor is displacement measurement based on the Hall principle. When the control current is constant, the Hall potential difference is proportional to the magnetic induction intensity, and the magnetic induction intensity is proportional to the position. Then the Hall potential difference is also proportional to the displacement. The displacement can be reflected by measuring the Hall potential difference; the stress value of the test part of sample 17 can be calculated by the calculation formula σ=K·X / A, where K is the spring elastic coefficient, X is the compressed length of the spring, and A is the cross-sectional area measured by sample 17; wherein, the principle of the compression spring providing the force is to use Hooke's law F=K·X.

[0049] In at least one embodiment, the probe working electrode 401 of the probe moving console 4 is arranged close to the surface of the sample 17, the output end of the three-dimensional positioning device 2 is electrically connected to the probe moving console 4 to control the precise movement of the probe working electrode 401 on the surface of the sample 17, and the input end of the three-dimensional positioning device 2 is electrically connected to the computer 1. The output end of the electrochemical workstation 5 is electrically connected to the probe working electrode 401, the counter electrode 12, and the reference electrode 14, and the input end of the electrochemical workstation 5 is electrically connected to the computer 1. The computer 1 is electrically connected to the three-dimensional positioning device 2 and the electrochemical workstation 5.

[0050] The stress corrosion micro-area in-situ electrochemical testing method of this embodiment uses the stress corrosion micro-area in-situ electrochemical testing device as described above to perform stress corrosion micro-area in-situ electrochemical testing operation on the sample 17, and specifically includes the following steps:

[0051] S1: Prepare the sample 17: Place the sample 17 to be tested inside the body of the stress loading device 3, and ensure that both ends of the sample 17 are connected to the first stress adjustment component and the second stress adjustment component respectively.

[0052] S2 applies stress: by adjusting the first stress adjustment component and the second stress adjustment component, a predetermined stress is applied to both ends of the sample 17 by a spring-type loading method, and the first displacement sensor 11 and the second displacement sensor 13 (FCD displacement sensor is selected) are used to monitor the displacement change during the stress loading process; specifically, the sample 17 is subjected to a tensile force by adjusting the outer nut, and the FCD displacement sensor records the distance of the nut moving by 10mm. According to the spring elastic coefficient K of 200N / mm and the cross-sectional area of ​​2.5mm×4mm, the tensile force on the end face of the sample 17 is calculated to be 200MPa. In at least one embodiment, the stress change can be achieved by adjusting the moving distance of the nut (variation range: 5mm to 20mm), or by replacing the compression spring with different elastic coefficients (K variation range: 100 to 300N / mm).

[0053] S3 immersing the sample 17: After a certain stress is applied to the sample 17, the sample 17 is immersed in a corrosion solution (3.5 wt % NaCl solution) contained in the body, and is ready for electrochemical testing;

[0054] S4 positioning the probe: using the three-dimensional positioning device 2 and the probe moving console 4, the probe working electrode 401 (diameter 10 microns) is accurately positioned to a predetermined test area on the surface of the sample 17 (5 microns away from the surface of the sample 17);

[0055] S5 electrochemical test: In-situ electrochemical test was performed by using the electrode assembly. A voltage of +0.3 V was applied to the probe working electrode 401 using the electrochemical workstation 5. The reference electrode 14 was Ag / AgCl and the counter electrode 12 was 1 cm in area. 2 A platinum sheet was used to perform a surface scanning test on the surface of sample 17, with a scanning area of ​​300μm×300μm, to evaluate the stress corrosion performance of sample 17;

[0056] S6 controls the movement of the probe: during the electrochemical test, the position of the probe working electrode 401 is adjusted as needed, and the probe movement console 4 controls the precise movement of the probe working electrode 401 on the surface of the sample 17 to achieve testing of different areas of the sample 17;

[0057] S7 Data collection and analysis: The electrochemical test data are collected by using the electrochemical workstation 5, and the data are analyzed by using the computer 1 connected to the test device and related software to determine the stress corrosion characteristics of the sample 17. One of the test results, such as Figure 8 As shown, a graph showing the change in surface pH of sample 17 was obtained.

[0058] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention, and these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A stress corrosion micro-area in-situ electrochemical testing device, characterized in that: The testing device includes a stress loading device, and the stress loading device includes: A body, wherein the body contains a sample to be tested; An electrode assembly, the electrode assembly being mounted in the body, the electrode assembly comprising a counter electrode and a reference electrode; a first stress adjustment component, the first stress adjustment component being applied to one end of the specimen by a spring-type loading method; a second stress regulating assembly, the second stress regulating assembly being applied to the other end of the specimen by a spring-type loading method; a first displacement sensor, wherein a probe of the first displacement sensor abuts against the first stress adjustment component; and a second displacement sensor, wherein a probe of the second displacement sensor abuts against the second stress adjustment component; When the testing device performs stress corrosion micro-area in-situ testing, the sample is immersed in a corrosion solution contained in the body after a certain stress is applied, and an in-situ electrochemical test is performed through the electrode assembly.

2. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The main body comprises an open steel base and a plastic base; the plastic base is placed inside the steel base.

3. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The first stress adjustment component includes a first pin hole bolt, a first high-elasticity compression spring and a first nut; one end of the first pin hole bolt is provided with a pin hole and extends through the side wall of the main body into the main body, and the first pin hole bolt is fastened to one end of the sample by a first pin that cooperates with the pin hole, and the first high-elasticity compression spring is arranged on the surface of the first pin hole bolt outside the side wall of the main body, and the other end of the first pin hole bolt is rotatably connected to the first nut.

4. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The second stress adjustment component includes a second pin hole bolt, a second high-elasticity compression spring and a second nut; the second stress adjustment component and the first stress adjustment component are symmetrically arranged on the two side walls of the main body; one end of the second pin hole bolt is provided with a pin hole and extends through the side wall of the main body into the main body, and the second pin hole bolt is fastened to the other end of the sample by a second pin that cooperates with the pin hole, the second high-elasticity compression spring is arranged on the surface of the second pin hole bolt outside the side wall of the main body, and the other end of the second pin hole bolt is rotatably connected to the second nut.

5. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The first displacement sensor is fixed on the side wall of the body and arranged parallel to the first pin hole bolt, and the probe of the first displacement sensor abuts against the first nut; the second displacement sensor is fixed on the side wall of the body and arranged parallel to the second pin hole bolt, and the probe of the second displacement sensor abuts against the second nut.

6. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The testing device also includes a three-dimensional positioning device and a probe moving console; the probe working electrode of the probe moving console is arranged close to the sample surface, the output end of the three-dimensional positioning device is electrically connected to the probe moving console to control the precise movement of the probe working electrode on the sample surface, and the input end of the three-dimensional positioning device is electrically connected to a computer.

7. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The testing device also includes an electrochemical workstation; the output end of the electrochemical workstation is electrically connected to the probe working electrode, the counter electrode and the reference electrode, and the input end of the electrochemical workstation is electrically connected to a computer.

8. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The testing device further includes a first display and a second display; the first display and the second display are electrically connected to the first displacement sensor and the second displacement sensor, respectively.

9. The stress corrosion micro-area in-situ electrochemical testing device according to claim 1, characterized in that: The testing device also includes a computer; the computer is electrically connected to the three-dimensional positioning device and the electrochemical workstation.

10. A stress corrosion micro-area in-situ electrochemical testing method, characterized in that: The testing method uses the stress corrosion micro-area in-situ electrochemical testing device according to any one of claims 1 to 9 to perform stress corrosion micro-area in-situ electrochemical testing operations on the sample, specifically comprising the following steps: S1: Prepare the sample: place the sample to be tested inside the body of the stress loading device, and ensure that both ends of the sample are connected to the first stress adjustment component and the second stress adjustment component respectively and are ready; S2 applying stress: by adjusting the first stress adjustment component and the second stress adjustment component, a predetermined stress is applied to both ends of the sample by a spring loading method, and at the same time, the first displacement sensor and the second displacement sensor are used to monitor the displacement change during the stress loading process; S3 immersion of the sample: After a certain stress is applied to the sample, the sample is immersed in the corrosion solution contained in the body to prepare for electrochemical testing; S4 positioning probe: Use the three-dimensional positioning device and the probe moving console to accurately position the probe working electrode to the predetermined test area on the sample surface; S5 electrochemical test: In-situ electrochemical test is performed through the electrode assembly. A specific voltage or current is applied to the probe working electrode using an electrochemical workstation, and a surface scanning test is performed on the sample surface to evaluate the stress corrosion performance of the sample. S6 controls the movement of the probe: During the electrochemical test, the position of the probe working electrode is adjusted as needed. The probe movement console controls the precise movement of the probe working electrode on the sample surface to achieve testing of different areas of the sample. S7 Data Collection and Analysis: The electrochemical test data is collected using an electrochemical workstation and analyzed using a computer connected to the test device and related software to determine the stress corrosion characteristics of the specimen.

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