Electrochemical behavior testing device and testing method under bidirectional stress loading

Abstract

The invention provides an electrochemical behavior test device and test method under bidirectional stress loading, the test device comprises a bidirectional loading device, a clamp, an electrochemical workstation, a bipolar power supply and a loading test assembly, the loading test assembly at least comprises an electrolytic cell assembly, a sample and a low-resistance adjustable electrolytic cell support, the electrolytic bath assembly comprises two electrolytic baths and a plurality of spring bolts, the electrolytic baths are arranged on the front side and the rear side of the sample respectively, and the two electrolytic baths are connected through the spring bolts and are in sealing fit with the sample; the low-resistance adjustable electrolytic cell bracket is connected with the electrolytic cell assembly, and the electrolytic cell assembly is supported on the sample; and the electrochemical workstation is matched with the bipolar power supply to test the hydrogen evolution and / or hydrogen diffusion behavior of the sample. According to the device and the method, the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material can be tested while the bidirectional load is applied to the sample, so that the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material can be researched in a stress state close to a real working condition.

Description

Technical Field

[0001] The present invention relates to the field of corrosion testing of titanium alloy materials, and in particular to a device and method for testing electrochemical behavior under bidirectional stress loading. Background Art

[0002] Titanium alloys are sensitive to hydrogen. The ingress of hydrogen can cause embrittlement, leading to decreased elongation, fracture toughness, and stress corrosion resistance, thus compromising the safety of titanium alloy structures. Titanium alloys are widely used in marine engineering applications, such as pressure vessels, pipelines, heat exchangers, fuel cell bipolar plates, and pressure-resistant structural shells. In these structures, the spatial scale to material thickness ratio is significantly greater than 10:1, resulting in a stress state similar to that of a thin shell structure, exhibiting a typical bidirectional stress state.

[0003] Existing research shows that under stress, the electrochemical behavior of the material surface and the diffusion behavior of hydrogen atoms within the material will change, and stress-induced hydrogen diffusion and stress-induced hydrogen enrichment phenomena exist. The typical hydrogen diffusion equation under stress is as follows:

[0004]

[0005]

[0006] Where C is the hydrogen concentration; D is the diffusion coefficient; R is the gas constant; T is the thermodynamic temperature; is the standard molar volume of hydrogen inside the metal; is the clean water pressure.

[0007] Traditional research on the electrochemical behavior and hydrogen diffusion behavior of metal materials is based on experiments in a static state without external stress, which is significantly different from the electrochemical hydrogen evolution process on the surface of titanium alloy materials under real working conditions and the diffusion behavior and diffusion rate of hydrogen in the structure.

[0008] The patent with publication number CN106872337A discloses an experimental device and method for electrochemical hydrogen permeation under constant stress loading, which belongs to the technical field of metal material performance testing. The device of the present invention mainly includes an electrochemical testing system and a mechanical stress loading device, which is mainly composed of a system for loading constant stress, an electrochemical workstation, a constant current meter, a ventilation device, a hydrogen permeation electrolytic cell, a saturated calomel electrode, a salt bridge, and an auxiliary platinum electrode. The device and method provided by the invention can measure the hydrogen diffusion coefficient of a material under different constant tensile stresses. The device can apply a maximum force of 6000N. The test stress depends on the size of the sample. The thinner the sample, the greater the stress that can be applied (the relationship between tension and tensile stress: Where: σ is tensile stress, unit MPa; F is tensile force, unit N; A is the cross-sectional area of ​​the specimen, unit mm2 The experimental device provided by this invention can detect the hydrogen permeation of the sample under uniaxial tension, but cannot simulate the hydrogen permeation of titanium alloy materials under biaxial stress, nor can it detect the hydrogen evolution of titanium alloy materials. Summary of the Invention

[0009] The technical problem solved by the present invention is that, in the prior art, it is impossible to detect hydrogen evolution and hydrogen diffusion of titanium alloy materials under bidirectional stress.

[0010] The present invention discloses an electrochemical behavior testing device under bidirectional stress loading, comprising:

[0011] Bidirectional loading device, used to provide bidirectional loading stress to the specimen;

[0012] A fixture, one end of which is used to clamp the sample, and the other end of which is connected to the bidirectional loading device for clamping and loading the sample;

[0013] A loading test assembly includes at least an electrolytic cell assembly, a specimen, and a low-resistance adjustable electrolytic cell support. The electrolytic cell assembly includes two electrolytic cells and a plurality of spring bolts. The two electrolytic cells are respectively arranged on the front and rear sides of the specimen and connected by the spring bolts. The two electrolytic cells are respectively sealed with the specimen. The electrolytic cells are used to set electrolyte and make the electrolyte contact the two sides of the specimen respectively. The low-resistance adjustable electrolytic cell support is connected to the electrolytic cell assembly and supports the electrolytic cell assembly on the specimen.

[0014] An electrochemical workstation, which is used to cooperate with one of the electrolytic cells and the sample to form an electrochemical detection assembly;

[0015] A bipolar power supply is used to cooperate with another electrolytic cell and a sample to form a bipolar detection component. The electrochemical detection component and the bipolar detection component are used to cooperate to test the hydrogen evolution and / or hydrogen diffusion behavior of the sample.

[0016] Furthermore, a connecting portion is provided on the side of the electrolytic cell close to the sample. The connecting portion is a hollow tubular structure. One end of the connecting portion is fixedly connected to the electrolytic cell, and the other end is provided with a connecting bevel. The connecting bevel is used to form a bevel matching structure with the sample.

[0017] Furthermore, the complementary angle between the connecting inclined surface and the vertical is recorded as α, and the value range of angle α is 160°-165°.

[0018] Furthermore, a sealing groove is provided on the connecting inclined surface, and the sealing groove is used to set a sealing ring, and the sealing ring is used to improve the sealing effect between the electrolytic cell and the sample.

[0019] Furthermore, the specimen is a cross-shaped specimen, which includes two pairs of load-bearing arms arranged in a cross shape, and a clamping portion is provided on the load-bearing arm at a position away from the center of the specimen. The clamping portion is insulated and is used to cooperate with the clamp to clamp the specimen, and a central thinning portion is provided at the center of the specimen. The central thinning portion is thinned relative to the thickness of the load-bearing arm, and an inclined transition zone is provided in the circumference of the central thinning portion, and the inclined transition zone is used to cooperate with the connecting bevel for sealing.

[0020] Furthermore, a plurality of stress relief grooves are provided on each load-bearing arm.

[0021] Furthermore, the thickness of the load-bearing arm of the specimen is recorded as a, the thickness of the central thinning portion is recorded as b, and the width of the inclined transition zone is recorded as c. The value range of c is 0.08a-0.125a, and the value range of b is 2.5a-3.5a.

[0022] Furthermore, the low-resistance adjustable electrolytic cell support includes a drag-reducing sliding ring, which is in rolling contact with the sample and is used to convert relative sliding into relative rolling when the low-resistance adjustable electrolytic cell support and the sample move relative to each other.

[0023] Furthermore, the low-resistance adjustable electrolytic cell bracket also includes a support link, a fastening bolt, an adjusting screw support block, an adjusting screw, a link support ring, an adjusting screw adjustment block and a thickness compensation support ring. There are four support links, and the upper ends of the four support links are fixed in pairs in the front and rear directions by fastening bolts, and the lower ends of the four support links are connected by the same spring bolt, so that the four support links form a V-shaped support structure in the front and rear directions. The link support ring is arranged between the support links on the front and rear sides. There are three link support rings, one of which is arranged at the lower ends of the four support links, and the other two are respectively arranged between the support links at the upper ends of the V-shape. There are two drag reduction sliding rings, which are respectively mounted on the V-shape. There are at least one pair of thickness compensation support rings on the two connecting rod support rings at the ends, and the pair of thickness compensation support rings is sleeved on one of the connecting rod support rings at the upper end of the V-shape, and is arranged on the front and rear sides of the drag reduction sliding ring sleeved on the connecting rod support ring. The outer diameter of the thickness compensation support ring is larger than the outer diameter of the drag reduction sliding ring, and is used to cooperate with the drag reduction sliding ring to form a moving guide structure. The adjusting screw support block, the adjusting screw and the adjusting screw adjustment block are used to cooperate to form an adjusting device, and the adjusting device is respectively arranged on the front and rear sides of the low-resistance adjustable electrolytic cell bracket, wherein a blind hole is provided on the adjusting screw support block, and a threaded through hole is provided on the adjusting screw adjustment block, and one end of the adjusting screw is threaded through the threaded through hole and then extends into the blind hole.

[0024] Furthermore, the loading test assembly also includes a tray, which is arranged on the lower side of the electrolytic cell assembly. A through hole is provided on the tray, and the lower end of the sample is clamped by a clamp after passing through the through hole.

[0025] The present invention also discloses a method for testing electrochemical behavior under bidirectional stress loading, using the above-mentioned testing device, and the testing method includes:

[0026] Step S1: start the bidirectional loading device and load the fixture;

[0027] Step S2: Assemble the sample, electrolytic cell, low-resistance adjustable electrolytic cell bracket, and tray, then install them on the fixture and tighten the fixture;

[0028] Step S3: Adjust the position of the sample and the electrolytic cell to ensure that the center of the chuck of the bidirectional loading device, the center of the sample, and the centers of the two electrolytic cells are in the same position;

[0029] Step S4: adjusting the bidirectional loading device so that the bidirectional loads are adjusted to preset target values;

[0030] Step S5: adding electrolyte to the two electrolytic cells;

[0031] Step S6: inserting electrodes into the electrolytic cells, combining the electrodes of one electrolytic cell with the sample and the electrochemical workstation to form an electrochemical detection assembly, and combining the electrodes of the other electrolytic cell with the sample, a bipolar power supply, and the electrochemical workstation to form a bipolar detection assembly;

[0032] Step S7: starting the electrochemical workstation, bipolar power supply, and corresponding components in the electrode to perform electrochemical behavior detection according to the electrochemical behavior to be tested;

[0033] Step S8: After the test is completed, turn off the electrochemical workstation and the bipolar power supply, remove the electrodes, drain the liquid in the electrolytic cell, remove the electrolytic cell and the sample, and end the test.

[0034] Compared with the prior art, the electrochemical behavior testing device and testing method under bidirectional stress loading described in the present invention have the following advantages:

[0035] The present invention, through the arrangement of a bidirectional loading device and a bidirectional electrolytic cell assembly, can apply a bidirectional load to the sample while also testing the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material, thereby being able to study the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material under a stress state close to the actual working condition, and provide an accurate reference basis for the composition and structure regulation and process improvement of the service material under corrosion and hydrogen environment conditions. The dynamic sealing of the electrolytic cell and the sample is achieved by the coordinated arrangement of the conical sealing surface and the spring bolt, effectively ensuring the sealing performance of the electrolytic cell. The sliding friction between the sample and the low-resistance adjustable electrolytic cell bracket is converted into rolling friction by the arrangement of the low-resistance adjustable electrolytic cell bracket, effectively reducing the influence of friction on the coaxiality of the electrolytic cell and the sample center during the deformation of the sample. In addition, the adjustable opening angle of the low-resistance adjustable electrolytic cell bracket can make the position of the electrolytic cell adapt to samples of different widths, so that it can be used with samples of various specifications. The testing device provided by the present invention has a simple structure and is easy to operate. It can study the hydrogen evolution and / or hydrogen diffusion behavior of titanium alloy materials under stress conditions close to real working conditions, and provides an effective reference basis for improving the hydrogen damage resistance and hydrogen-induced cracking stress corrosion resistance of titanium alloy materials, and for improving the anti-structure, composition optimization, process adjustment, and material optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a front view of the electrochemical behavior testing device under bidirectional stress loading according to an embodiment of the present invention;

[0037] Figure 2 Schematic diagram of the three-dimensional structure of the electrochemical behavior testing device under bidirectional stress loading according to an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the three-dimensional structure of the sample, electrolytic cell assembly, low-resistance adjustable electrolytic cell support, and tray assembled in accordance with an embodiment of the present invention;

[0039] Figure 4 Schematic diagram of the three-dimensional structure of the sample according to the embodiment of the present invention;

[0040] Figure 5 A schematic diagram of the cross-sectional structure of the central thinning position according to an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the three-dimensional structure of the low-resistance adjustable electrolytic cell support according to an embodiment of the present invention;

[0042] Figure 7 This is a schematic diagram of the exploded structure of the low-resistance adjustable electrolytic cell support according to an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the three-dimensional structure of the electrolytic cell according to an embodiment of the present invention with the upper cover removed;

[0044] Figure 9 This is a side view of the electrolytic cell according to an embodiment of the present invention with the upper cover removed;

[0045] Figure 10 for Figure 9 Schematic diagram of the cross-sectional structure of the AA part.

[0046] Description of reference numerals:

[0047] 100. Bidirectional loading device; 110. Loading arm; 200. Clamp; 300. Loading test assembly; 310. Specimen; 311. Clamping part; 312. Stress relief groove; 313. Central thinning part; 314. Inclined transition zone; 315. Chamfered corner; 320. Electrolytic cell; 321. Auxiliary electrode; 322. Reference electrode; 323. Connecting part; 324. Sealing groove; 325. Connecting slope; 330. Low resistance adjustable electrolytic cell bracket; 331. Supporting connecting rod; 332. Fastening bolt; 333. Adjusting screw support block; 334. Adjusting screw; 335. Connecting rod support ring; 336. Adjusting screw adjustment block; 337. Drag reduction sliding ring; 338. Thickness compensation support ring; 340. Spring bolt; 350. Tray; 400. Electrochemical workstation; 500. Bipolar power supply. DETAILED DESCRIPTION

[0048] To make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the embodiments described are part of the embodiments of the present invention, rather than all of the embodiments. The specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention. It should be noted that, unless there is a conflict, the features in the embodiments and embodiments of the present invention may be combined with each other.

[0049] The following describes in detail an electrochemical behavior testing device and testing method under bidirectional stress loading according to an embodiment of the present invention with reference to the accompanying drawings.

[0050] Example 1

[0051] This embodiment provides an electrochemical behavior testing device under bidirectional stress loading, such as Figures 1-10 As shown, the test device is used to detect the hydrogen evolution and / or hydrogen diffusion behavior of titanium alloy materials under biaxial stress loading, and the test device includes:

[0052] The bidirectional loading device 100 is used to provide bidirectional loading stress to the sample 310;

[0053] A fixture 200 , one end of which is used to clamp the sample 310 , and the other end of which is connected to the bidirectional loading device 100 for clamping and loading the sample 310 ;

[0054] The loading test assembly 300 includes at least an electrolytic cell assembly, a sample 310, and a low-resistance adjustable electrolytic cell support 330. The electrolytic cell assembly includes two electrolytic cells 320 and a plurality of spring bolts 340. The two electrolytic cells 320 are respectively arranged on the front and rear sides of the sample 310 and connected by the spring bolts 340. The two electrolytic cells 320 are respectively sealed with the sample 310. The electrolytic cells 320 are used to set electrolyte and make the electrolyte contact the two sides of the sample 310 respectively. The low-resistance adjustable electrolytic cell support 330 is connected to the electrolytic cell assembly and supports the electrolytic cell assembly on the sample 310.

[0055] An electrochemical workstation 400 , which is used to cooperate with one of the electrolytic cells 320 and the sample 310 to form an electrochemical detection assembly;

[0056] A bipolar power supply 500 is used to cooperate with another electrolytic cell 320 and a sample 310 to form a bipolar detection assembly. The electrochemical detection assembly and the bipolar detection assembly are used to cooperate to test the hydrogen evolution and / or hydrogen diffusion behavior of the sample 310.

[0057] Through the above-mentioned arrangement, bidirectional loading stress can be provided to the sample 310, thereby accurately simulating the stress state of the titanium alloy material under the actual working state, effectively improving the accuracy of the test results. By setting the two electrolytic cells 320 and the spring bolts 340 in the electrolytic cell assembly, an independent electrolytic chamber is formed on both sides of the sample 310, which is conducive to the testing of hydrogen evolution and hydrogen diffusion behavior. In addition, the two electrolytic cells 320 are fastened together by the spring bolts 340, so that the pressure of the two electrolytic cells 320 and the sample 310 can be adjusted simultaneously through a set of spring bolts 340, and the pressure applied by the two electrolytic cells 320 to the sample 310 is balanced, thereby reducing the influence of other factors on the test results and improving the detection accuracy. By setting the electrochemical workstation 400 and the bipolar power supply 500, the two form a detection assembly with one electrolytic cell 320 respectively, so that the test device provided in this example can perform hydrogen evolution behavior test and hydrogen diffusion behavior test on the sample 310 prepared from titanium alloy material separately, thereby significantly improving the test efficiency. It should be noted that the before and after refers to Figure 1The front-to-back direction is in the case of the main view. The electrochemical workstation 400 cooperates with one of the electrolytic cells 320 and the sample 310 to form an electrochemical detection component, and the bipolar power supply 500 cooperates with the other electrolytic cell 320 and the sample 310 to form a bipolar detection component. Both are achieved through the electrical connection of relevant components, which will not be described in detail here. Specifically, the clamp 200 is provided with four, which are arranged in pairs in the up-down and left-right directions, respectively, for clamping the sample 310 in the up-down and left-right directions. The bidirectional loading device 100 is provided with a loading arm 110 corresponding to each clamp 200. The loading arm 110 is connected to the clamp 200 and is used to apply a bidirectional load in the up-down and left-right directions to the sample 310. Optionally, the bidirectional loading device 100 can be a bidirectional tensile testing machine or other device capable of achieving bidirectional loading. A cavity is formed inside the electrolytic cell 320 to accommodate the electrolyte. For details, reference can be made to the prior art. The specific structure of the clamp 200 is not an improvement of the present invention. For details, reference can be made to the prior art, which will not be described in detail here. Preferably, the center of the electrolytic cell 320 is coaxially arranged with the center of the sample 310 to ensure uniformity of force applied to the sample 310 .

[0058] As a preferred example, the sample 310 and the electrolytic cell 320 are sealed by a conical surface. This conical surface seal effectively improves the dynamic sealing effect between the sample 310 and the electrolytic cell 320 and can also automatically align the sample 310 when it undergoes certain deformation, thereby improving the sealing effect between the sample 310 and the electrolytic cell 320.

[0059] As one example, Figures 8-10 As shown, a connecting portion 323 is provided on the side of the electrolytic cell 320 near the sample 310. The connecting portion 323 is a hollow tubular structure. One end of the connecting portion 323 is fixedly connected to the electrolytic cell 320, and the other end is provided with a connecting bevel 325. The connecting bevel 325 is used to form an inclined surface matching structure with the sample 310. It should be understood that the hollow tubular structure of the connecting portion 323 allows the electrolyte in the electrolytic cell 320 to contact the surface of the sample 310 through the connecting portion 323, thereby facilitating hydrogen evolution and / or hydrogen diffusion testing. The formation of an inclined surface matching structure between the connecting bevel 325 and the sample 310 facilitates dynamic sealing between the electrolytic cell 320 and the sample 310 under the action of the spring bolt 340, thereby effectively improving the sealing effect between the electrolytic cell 320 and the sample 310. It should be understood that a central thinning portion 313 is provided at the center of the sample 310 , and the central thinning portion 313 is thinned relative to other parts of the sample 310 . An inclined transition zone 314 is provided around the central thinning portion 313 , and the inclined transition zone 314 forms an inclined surface matching structure with the connecting inclined surface 325 .

[0060] Better, such as Figure 10 As shown, the complementary angle between the connecting bevel 325 and the vertical is denoted as α, and the value of α ranges from 160° to 165°. Preferably, the value of α is 161.57°. The value of α can be obtained through finite element simulation, which can cooperate with the specimen 310 to achieve automatic centering, improve the reliability of the seal, optimize stress distribution, reduce test loads, and enhance the adaptability of the seal.

[0061] As a preferred example, a sealing groove 324 is provided on the connecting bevel 325. This sealing groove 324 is used to accommodate a sealing ring (not shown in the drawings). The sealing ring is used to enhance the sealing effect between the electrolytic cell 320 and the specimen 310. The provision of this sealing ring effectively enhances the sealing effect between the electrolytic cell 320 and the specimen 310, maintaining the corresponding sealing effect even if the specimen 310 undergoes some deformation during the test. Combined with the beveled mating structure formed by the connecting bevel 325 and the specimen 310, and the provision of the spring bolt 340, the electrolytic cell 320 and the specimen 310 exhibit a certain tendency to automatically align. This maintains the sealing performance between the electrolytic cell 320 and the specimen 310 even when the specimen 310 deforms, ensuring smooth testing. Optionally, the sealing ring is an O-ring. Preferably, a non-water-soluble sealing grease is applied to the surfaces of the connecting bevel 325 and the sealing ring during assembly to further enhance the sealing performance.

[0062] Furthermore, if Figure 3 As shown, the loading test assembly 300 also includes a tray 350, which is arranged on the lower side of the electrolytic cell assembly. A through hole is provided on the tray 350, and the lower end of the sample 310 is clamped by the fixture 200 after passing through the through hole. Preferably, the inner hole of the through hole is slightly larger than the sample 310, so that the gap between the two is small while ensuring that the sample 310 passes through. The gap is filled with an oily sealing filler, such as plasticine. Through the above arrangement, even if a certain amount of electrolyte leakage occurs during the test, it can be collected by the tray 350, thereby protecting the bidirectional loading device 100 and the fixture 200 from being corroded by the electrolyte and ensuring the safety of the test device. Preferably, the tray 350 is abutted against the top of the fixture 200 after being set. Through this arrangement, the fixture 200 can be used to support the tray 350, so that no other supporting device is required, which simplifies the device structure and improves assembly efficiency.

[0063] As an example of an option, Figure 6 、 Figure 7As shown, the low-resistance adjustable electrolytic cell support 330 includes a drag-reducing sliding ring 337, which is in rolling contact with the sample 310 and is used to convert relative sliding into relative rolling when the low-resistance adjustable electrolytic cell support 330 and the sample 310 move relative to each other. The rolling contact between the drag-reducing sliding ring 337 and the sample 310 significantly reduces the resistance between the sample 310 and the low-resistance adjustable electrolytic cell support 330, converting relative sliding between the two into relative rolling, significantly reducing the resistance between the two, and reducing the impact of friction caused by deformation of the sample 310 on the coaxiality of the center of the electrolytic cell 320 and the center of the sample 310.

[0064] Specifically, such as Figure 6 、 Figure 7As shown, the low-resistance adjustable electrolytic cell bracket 330 also includes a support link 331, a fastening bolt 332, an adjusting screw support block 333, an adjusting screw 334, a link support ring 335, an adjusting screw adjustment block 336 and a thickness compensation support ring 338. There are four support links 331, and the upper ends of the four support links 331 are connected and fixed in pairs in the front and rear directions by fastening bolts 332. The lower ends of the four support links 331 are connected by the same spring bolt 340, so that the four support links 331 form a V-shaped support structure in the front and rear directions. The link support ring 335 is arranged between the support links 331 on the front and rear sides. There are three link support rings 335, one of which is arranged at the lower ends of the four support links 331, and the other two are respectively arranged between the support links 331 at the upper ends of the V-shape. There are two drag reduction sliding rings 337, which are respectively sleeved On the two connecting rod support rings 335 at the upper end of the V-shape, there is at least a pair of thickness compensation support rings 338, and the pair of thickness compensation support rings 338 is sleeved on one of the connecting rod support rings 335 at the upper end of the V-shape, and is arranged on the front and rear sides of the drag reduction sliding ring 337 sleeved on the connecting rod support ring 335. The outer diameter of the thickness compensation support ring 338 is larger than the outer diameter of the drag reduction sliding ring 337, and is used to cooperate with the drag reduction sliding ring 337 to form a moving guide structure. The adjusting screw support block 333, the adjusting screw 334 and the adjusting screw adjustment block 336 are used to cooperate to form an adjustment device, and the adjusting device is respectively arranged on the front and rear sides of the low-resistance adjustable electrolytic cell bracket 330, wherein a blind hole is provided on the adjusting screw support block 333, and a threaded through hole is provided on the adjusting screw adjustment block 336. One end of the adjusting screw 334 is threaded through the threaded through hole and then extends into the blind hole. It should be understood that there can also be two pairs of thickness compensation support rings 338, and the two pairs of thickness compensation support rings 338 are respectively arranged on the two connecting rod support rings 335 at the upper end of the V-shape, and each pair of thickness compensation support rings 338 are respectively arranged on the front and rear sides of the drag reduction sliding ring 337 mounted on its corresponding connecting rod support ring 335. Through the above arrangement, when installing the electrolytic cell 320, a spring bolt 340 close to the lower side of the electrolytic cell 320 is passed through the support link 331 and the link support ring 335 and then fastened to another electrolytic cell 320, so that the electrolytic cell 320 can be connected to the low-resistance adjustable electrolytic cell bracket 330. At this time, the upper end of the V-shape on the low-resistance adjustable electrolytic cell bracket 330 is located on the upper side of the sample 310, and the drag-reducing sliding ring 337 is in rolling contact with the sample 310. Then, by adjusting the adjusting screw 334, the opening of the V-shape is adjusted to drive the electrolytic cell 320 to move in the vertical direction, so as to facilitate the adjustment of the coaxiality of the center of the electrolytic cell 320 and the sample 310.The coordinated arrangement of the low-resistance adjustable electrolytic cell support 330 and the electrolytic cell 320 allows for rapid adjustment of the center of the electrolytic cell 320, facilitating its assembly with the specimen 310. Furthermore, the provision of the drag-reducing sliding ring 337 transforms the relative movement between the specimen 310 and the low-resistance adjustable electrolytic cell support 330 from relative sliding to relative rolling, significantly reducing frictional resistance and improving ease of adjustment. Specifically, in this example, the axial length of the drag-reducing sliding ring 337 is slightly less than the axial length of the connecting rod support ring 335 and slightly greater than the thickness of the specimen 310. The thickness-compensating support ring 338 is disposed on both sides of the drag-reducing sliding ring 337 and has an outer diameter greater than that of the drag-reducing sliding ring 337. This allows the thickness-compensating support ring 338 and the drag-reducing sliding ring 337 to form a groove-like structure. This groove-like structure facilitates position limiting and guiding when the specimen 310 and the electrolytic cell 320 undergo relative displacement, ensuring the stability of the movement of the electrolytic cell 320. Preferably, the inner diameter of the drag-reducing sliding ring 337 is coated with grease or graphite and then sleeved on the connecting rod support ring 335 , thereby ensuring that it can roll smoothly relative to the connecting rod support ring 335 .

[0065] Specifically, there are two low-resistance adjustable electrolytic cell supports 330, which are respectively arranged on two opposite load-bearing arms in the left and right directions of the sample 310. This arrangement can ensure the balance performance of the electrolytic cell 320 and achieve stable contact between the sample 310 and the electrolytic cell 320.

[0066] Specifically, such as Figure 4As shown, the specimen 310 is a cross-shaped specimen, comprising two pairs of cross-shaped load-bearing arms. A clamping portion 311 is provided on each of the load-bearing arms, away from the center of the specimen 310. The clamping portion 311 is insulated and is used to cooperate with the fixture 200 to clamp the specimen 310. A central thinning portion 313 is provided at the center of the specimen 310. The central thinning portion 313 is thinner than the thickness of the load-bearing arms. An inclined transition region 314 is provided circumferentially of the central thinning portion 313. The inclined transition region 314 is configured to seal with the connecting bevel 325. The inclined transition region 314 is a tapered surface, and its sealing with the connecting bevel 325 can enhance the dynamic sealing effect between the electrolytic cell 320 and the specimen 310. The provision of the central thinning portion 313 can reduce the test load. Finite element analysis shows that when the specimen 310 is within the elastic loading range, the ratio of the stress on the two end arms to the Mises stress in the central thinning region is approximately 1:5.27, and the ratio of the stress in any direction of force is approximately 1:6.13. This results in a low test load and a relatively short diffusion time, which helps ensure stable test performance and effectively improves test efficiency. Preferably, the inclination angle of the inclined transition zone 314 matches the inclination angle of the connecting bevel 325 to achieve a good sealing effect. Through the coordinated arrangement of the inclined transition zone 314 and the connecting bevel 325, the electrolytic cell 320 and the specimen 310 tend to self-align under the action of the spring bolt 340, thereby achieving both centering and sealing effects. It should be noted that the insulation treatment can be performed by coating or spraying an insulating material, or by sheathing an insulating material on the surface of the clamping portion 311. For details, please refer to the existing art and will not be elaborated here.

[0067] Better, such as Figure 4 As shown, each load-bearing arm is provided with a plurality of stress-relief grooves 312. These stress-relief grooves 312 are through-grooves that effectively prevent premature fracture caused by stress concentration at right angles to the cross-shaped specimen. Preferably, a fillet 315 is formed between two mutually perpendicular load-bearing arms, with a radius of 4 mm or greater. This arrangement further reduces stress concentration, thereby improving the fracture resistance of the specimen 310 during testing.

[0068] Specifically, such as Figure 5 As shown, the thickness of the load-bearing arm of specimen 310 is denoted as a, the thickness of the central thinned portion 313 is denoted as b, and the width of the inclined transition zone 314 is denoted as c. The value range of c is 0.08a-0.125a, and the value range of b is 2.5a-3.5a. Preferably, c = 0.1a and b = 3a. This configuration significantly reduces the thickness of specimen 310 at its center, significantly reducing the test load, shortening the hydrogen diffusion time, and improving test efficiency.

[0069] Specifically, an auxiliary electrode 321 and a reference electrode 322 are provided on the upper cover of an electrolytic cell 320 in the electrolytic cell assembly, the auxiliary electrode 321 in the electrolytic cell 320 is connected to the negative pole of the electrochemical workstation 400, and the sample 310 is connected to the positive pole of the electrochemical workstation 400, so as to form an electrochemical detection assembly, wherein the reference electrode 322 is used to detect changes in the electrode potential in the electrolytic cell 320; another auxiliary electrode 321 is provided on the upper cover of another electrolytic cell 320 in the electrolytic cell assembly, the auxiliary electrode 321 is connected to the positive pole of the bipolar power supply 500, and the sample 310 is connected to the negative pole of the bipolar power supply 500, so as to form a bipolar detection assembly. By setting up two electrolytic cells 320 in sealed contact with the sample 310, the two sides of the sample 310 are independently exposed to the electrolyte, and the reactions on both sides do not interfere with each other, eliminating cross-interference between the two and improving the reliability of the test results. Combined with the setting of the bidirectional loading device 100, the sample 310 can accurately simulate the loading state of the titanium alloy material in the actual use environment, making the test results closer to the actual working environment and significantly improving the test accuracy. Optionally, the auxiliary electrode 321 is a platinum electrode.

[0070] In practice, two electrolytic cells 320 are suspended from the left and right lateral load-bearing arms of the cross-shaped specimen via low-resistance adjustable cell supports 330. Two spring bolts 340 at the bottom of the cells 320 also serve as the central rotation bolts for the low-resistance adjustable cell supports 330. The clamping portion 311 of the specimen 310, after being insulated, is clamped by the fixture 200 of the bidirectional loading device 100. The adjusting screw 334 on the low-resistance adjustable cell supports 330 is adjusted to ensure that the center of the solution channel (connection portion 323) on the electrolytic cell 320 is aligned with the center of the specimen 310. Specimen 310 is a cross-shaped, plate-shaped specimen with a thinned center. In addition to the thinning at the center, each of the four load-bearing arms is equipped with stress relief grooves 312 to prevent stress concentration at the right angles of the cross-shaped specimen, which could lead to premature fracture. An O-ring seal is used between the electrolytic cell 320 and the sample 310. Sealing is achieved by the inclined transition zone 314 circumferentially surrounding the central thinned portion 313 of the sample 310. A non-water-soluble sealing grease is applied to the seal ring, the inclined transition zone 314, and / or the connecting bevel 325 to enhance sealing. After tightening the spring bolt 340, the spring's elasticity maintains pressure between the two electrolytic cells 320 and the sample 310, further ensuring sealing. A tray 350 is provided below the electrolytic cell 320, and an oily sealing filler such as plasticine is filled between the tray 350 and the sample 310 to protect the bidirectional loading device 100 from corrosion by the solution in the event of leakage from the electrolytic cell 320. The auxiliary electrode 321 and the reference electrode 322 are supported by the upper cover of the electrolytic cell 320. The electrolytic cell 320 on one side is connected to the electrochemical workstation 400 to measure the transferred hydrogen element through electrochemical reaction to study the hydrogen diffusion behavior in the sample 310; the electrolytic cell 320 on the other side is connected to the bipolar power supply 500 to apply a voltage capable of precipitating hydrogen gas, and to precipitate hydrogen on the surface of the sample 310 to establish a steady-state transfer environment for hydrogen diffusion. In addition, the electrochemical workstation 400 can also be used to conduct hydrogen evolution research to explore the electrochemical kinetics of hydrogen evolution under stress on the surface of the material. It should be noted that the upper and lower, left and right in this example are Figure 1The corresponding orientations in the figure are consistent. During use, the auxiliary electrode 321 and the reference electrode 322 are respectively connected to the electrochemical workstation 400 and / or the bipolar power supply 500 via wires (not shown in the figures). The sample 310 serves as a working electrode for both the electrochemical workstation 400 and the bipolar power supply 500, connecting the sample 310 to the negative terminal of the bipolar power supply 500 and the positive terminal of the electrochemical workstation 400. The angle of the connecting bevel 325 on the electrolytic cell 320 and the inclined transition zone 314 on the sample 310 are the same, providing a certain degree of dynamic sealing between the two. This ensures that the electrolyte does not leak even when the sample 310 undergoes minor strain deformation. Furthermore, because the connecting bevel 325 and the inclined transition zone 314 form a tapered mating structure, the sample 310 and the electrolytic cell 320 tend to automatically align under the action of the spring bolt 340, ensuring the coaxiality of the centers of the two when the sample 310 undergoes slight strain deformation.

[0071] The spring bolt 340 can provide pressure between the electrolytic cell 320 and the sample 310 by the spring when tightened, ensuring the sealing pressure without generating excessive friction, and can maintain the sealing between the sample 310 and the electrolytic cell 320 when the sample 310 is slightly strained or moved.

[0072] The two electrolytic cells 320 in the electrolytic cell assembly are of completely identical design. Electrolytes of equal weight are placed in the two electrolytic cells 320 to ensure that the center of gravity of the entire test device is at the center of the sample 310. The electrolytic cell assembly can maintain balance under the support of the low-resistance adjustable electrolytic cell bracket 330.

[0073] The low-resistance adjustable electrolytic cell bracket 330 adopts the form of an adjustable screw 334 to adjust the hinged support link 331. The two spring bolts 340 at the bottom of the electrolytic cell 320 have the functions of clamping the electrolytic cell 320 and serving as the hinge center of the low-resistance adjustable electrolytic cell bracket 330 to support the electrolytic cell 320. The contact position between the low-resistance adjustable electrolytic cell support 330 and the sample 310 adopts a method of nesting a drag-reducing sliding ring 337 outside a connecting rod support ring 335 to form a form similar to a sliding bearing, which converts the sliding friction between the sample 310 and the low-resistance adjustable electrolytic cell support 330 into rolling friction, thereby reducing the influence of friction on the coaxiality of the electrolytic cell 320 and the sample 310 during the deformation of the sample 310. The drag-reducing sliding ring 337 is made of copper alloy material and coated with grease to further reduce friction. The height of the electrolytic cell 320 relative to the sample 310 is adjusted by adjusting the adjusting screw 334 to control the opening angle of the low-resistance adjustable electrolytic cell support 330 to adjust the height of the electrolytic cell 320 relative to the sample 310, so as to adapt to samples of different widths.

[0074] It should be noted that the testing device provided in this example can also collect data such as the open circuit potential, polarization curve, impedance spectrum, etc. of metal materials under bidirectional stress that can reflect the corrosion behavior of the material. After the test is completed and the data is saved, the electrochemical workstation 400 and the bipolar power supply 500 are turned off, the wire connection is disconnected, and the electrodes are removed. The electrolyte and the water used for counterweights are siphoned away using a plastic tube. After the extraction is completed, the electrolytic cell 320 and the sample 310 are removed, the bidirectional loading device 100 is adjusted to restore to its original state, the clamp 200 is loosened, and the sample 310 is removed.

[0075] Example 2

[0076] This embodiment provides a method for testing electrochemical behavior under bidirectional stress loading, which is used in the testing device described in Example 1. The testing method includes:

[0077] Step S1: start the bidirectional loading device and load the fixture;

[0078] Step S2: Assemble the sample, electrolytic cell, low-resistance adjustable electrolytic cell bracket, and tray, then install them on the fixture and tighten the fixture;

[0079] Step S3: Adjust the position of the sample and the electrolytic cell to ensure that the center of the chuck of the bidirectional loading device, the center of the sample, and the centers of the two electrolytic cells are in the same position;

[0080] Step S4: adjusting the bidirectional loading device so that the bidirectional loads are adjusted to preset target values;

[0081] Step S5: adding electrolyte to the two electrolytic cells;

[0082] Step S6: inserting electrodes into the electrolytic cells, combining the electrodes of one electrolytic cell with the sample and the electrochemical workstation to form an electrochemical detection assembly, and combining the electrodes of the other electrolytic cell with the sample, a bipolar power supply, and the electrochemical workstation to form a bipolar detection assembly;

[0083] Step S7: starting the electrochemical workstation, bipolar power supply, and corresponding components in the electrode to perform electrochemical behavior detection according to the electrochemical behavior to be tested;

[0084] Step S8: After the test is completed, turn off the electrochemical workstation and the bipolar power supply, remove the electrodes, drain the liquid in the electrolytic cell, remove the electrolytic cell and the sample, and end the test.

[0085] The specific test method details include: starting the bidirectional loading device, installing the fixture, adjusting the fixture position to be able to install the sample, assembling the cross-shaped center thinned sample and the low-resistance adjustable electrolytic cell bracket, electrolytic cell and tray, and installing them on the fixture. The tray is in direct contact with the lower fixture. After tightening the fixture, adjust the sample position and the electrolytic cell position to ensure that the centers of the four chucks of the bidirectional loading device (or the centers of the four fixtures), the center of the cross-shaped sample, and the centers of the two electrolytic cells are in the same position, and non-hydrophilic sealing filler is filled between the tray and the sample; adjust the bidirectional loading device, wait until the loads in both directions are adjusted to the preset target values, further tighten the spring bolts, add electrolyte to the two electrolytic cells, insert electrodes into the electrolytic cells, and connect the sample and electrodes through wires. The electrochemical workstation and bipolar power supply can be used to begin testing. Operating the electrochemical workstation alone can collect data on the sample's electrochemical behavior under bipolar loading, including data on the electrochemical kinetics of hydrogen atoms, for hydrogen evolution analysis. To measure hydrogen diffusion, first turn on the power supply, adjust the voltage, and ensure the sample is connected to the negative pole of the bipolar power supply. When trace bubbles emanate from the sample surface, indicating hydrogen generation, the electrochemical workstation is then adjusted to ensure the sample polarity is positive. By monitoring changes in potential and current, the time it takes for hydrogen to diffuse from one side of the bipolar power supply to the workstation is determined, and the diffusion coefficient is calculated. By performing different tests with different parameters, the parameters in the equation can be calculated, allowing the diffusion behavior of hydrogen in the material to be studied. After the test is complete and the data is saved, turn off the electrochemical workstation and bipolar power supply, disconnect the wires, remove the electrodes, and use a plastic tube to siphon away the electrolyte and counterweight water. Once the extraction is complete, remove the electrolytic cell and sample, adjust the bipolar loading device to its original state, loosen the clamp, remove the sample, and the test is complete.

[0086] Through the above-mentioned setting, while applying bidirectional loads to the sample, the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material can also be tested, thereby being able to study the hydrogen evolution and / or hydrogen diffusion behavior of the titanium alloy material under stress conditions close to the actual working conditions, providing an accurate reference basis for the composition and structure control and process improvement of the service materials under corrosion and hydrogen environment conditions.

[0087] Specifically, an auxiliary electrode and a reference electrode are provided on the upper cover of one electrolytic cell, and both the auxiliary electrode and the reference electrode are connected to an electrochemical workstation. An auxiliary electrode is provided on the upper cover of the other electrolytic cell, and the auxiliary electrode is connected to a bipolar power supply. In step S7, starting the electrochemical workstation, the bipolar power supply, and corresponding components of the electrode to perform electrochemical behavior detection according to the electrochemical behavior to be tested includes:

[0088] Step S71: Determine the test content to be performed, test the hydrogen evolution behavior alone, and execute step S72; test the hydrogen diffusion behavior alone, and execute step S73; test the hydrogen evolution behavior and hydrogen diffusion behavior simultaneously, and execute step S74;

[0089] Step S72: starting the electrochemical workstation and the auxiliary electrode and reference electrode in the electrolytic cell connected thereto to perform a hydrogen evolution behavior test;

[0090] Step S73: starting the electrochemical workstation and the auxiliary electrode and reference electrode in the electrolytic cell connected thereto, starting the bipolar power supply and the auxiliary electrode in the electrolytic cell connected thereto, and performing a hydrogen diffusion behavior test;

[0091] Step S74: Start the electrochemical workstation and the auxiliary electrode and reference electrode in the electrolytic cell connected thereto to perform a hydrogen evolution behavior test; after the hydrogen evolution behavior test, start the electrochemical workstation and the auxiliary electrode and reference electrode in the electrolytic cell connected thereto, start the bipolar power supply and the auxiliary electrode in the electrolytic cell connected thereto to perform a hydrogen diffusion behavior test.

[0092] In step S72, the sample is connected to the positive electrode of the electrochemical workstation, the auxiliary electrode is connected to the negative electrode of the electrochemical workstation, and the reference electrode monitors the potential in the electrolytic cell in real time to perform a hydrogen evolution behavior test;

[0093] In step S73, the sample is connected to the positive electrode of the electrochemical workstation, the auxiliary electrode in the electrolytic cell corresponding to the electrochemical workstation is connected to the negative electrode of the electrochemical workstation, the sample is connected to the negative electrode of the bipolar power supply, the auxiliary electrode in the electrolytic cell corresponding to the bipolar power supply is connected to the positive electrode of the bipolar power supply, the electrolytic cell corresponding to the bipolar power supply serves as a hydrogen charging cell, the sample serves as a cathode for hydrogen evolution, and becomes a hydrogen permeation source, the electrolytic cell corresponding to the electrochemical workstation serves as a detection cell, the sample is connected to the positive electrode of the electrochemical workstation, and the hydrogen atoms transferred from the anodic oxidation are used to monitor the permeation current using the electrochemical workstation, thereby conducting corresponding hydrogen diffusion behavior research, and the reference electrode is used to monitor the potential change in the detection cell and assist in calculating the hydrogen diffusion time;

[0094] In step S74, during the hydrogen evolution behavior test phase, the sample is connected to the positive electrode of the electrochemical workstation, the auxiliary electrode is connected to the negative electrode of the electrochemical workstation, and the reference electrode monitors the potential in the electrolyzer in real time to perform a hydrogen evolution behavior test; during the hydrogen diffusion behavior test phase, the sample is connected to the positive electrode of the electrochemical workstation, the auxiliary electrode in the electrolyzer corresponding to the electrochemical workstation is connected to the negative electrode of the electrochemical workstation, the sample is connected to the negative electrode of the bipolar power supply, the auxiliary electrode in the electrolyzer corresponding to the bipolar power supply is connected to the positive electrode of the bipolar power supply, the electrolyzer corresponding to the bipolar power supply serves as a hydrogen charging tank, the sample serves as a cathode for hydrogen evolution, and becomes a hydrogen permeation source, the electrolyzer corresponding to the electrochemical workstation serves as a detection tank, the sample is connected to the positive electrode of the electrochemical workstation, and the hydrogen atoms transferred from the anodic oxidation are used to monitor the permeation current using the electrochemical workstation to perform corresponding hydrogen diffusion behavior research, and the reference electrode is used to monitor the potential change in the detection tank and assist in calculating the time of hydrogen diffusion. It should be understood that the simultaneous testing of hydrogen evolution behavior and hydrogen diffusion behavior described in this application means that during a single clamping test process, both hydrogen evolution behavior testing and hydrogen diffusion behavior testing are performed, and the two are performed sequentially, not synchronously in time.

[0095] Through the above settings, corresponding electrochemical behavior test analysis can be carried out according to specific needs. The equipment can accurately simulate the actual stress conditions of titanium alloy material specimens, thereby facilitating the detection of electrochemical behaviors such as hydrogen evolution and / or hydrogen diffusion under real working conditions, and providing an accurate reference basis for the composition and structure control and process improvement of service materials under corrosion and hydrogen environment conditions.

[0096] It should be noted that all terms used in the present invention to indicate direction and position, such as: "up", "down", "left", "right", "front", "back", "vertical", "horizontal", "inside", "outside", "top", "low", "tail end", "head end", "center", etc., are only used to explain the relative position relationship and connection status between the components in a certain state, and are only for the convenience of describing the present invention, rather than requiring the present invention to be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention. In addition, the descriptions of "first", "second", etc. in the present invention are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which both A and B are satisfied.

[0097] In the present invention, unless otherwise specified or limited, the terms "connection" and "fixation" should be understood in a broad sense. For example, "fixation" can mean fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will be able to understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0098] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. An electrochemical behavior testing device under bidirectional stress loading, characterized in that: include: A bidirectional loading device (100) is used to provide bidirectional loading stress to the specimen (310); A clamp (200), one end of the clamp (200) is used to clamp the sample (310), and the other end of the clamp (200) is connected to the bidirectional loading device (100) and is used for clamping and loading the sample (310); A loading test assembly (300) comprises at least an electrolytic cell assembly, a sample (310) and a low-resistance adjustable electrolytic cell support (330), wherein the electrolytic cell assembly comprises two electrolytic cells (320) and a plurality of spring bolts (340), wherein the two electrolytic cells (320) are respectively arranged on the front and rear sides of the sample (310), and the two electrolytic cells (320) are connected via spring bolts (340), and the two electrolytic cells (320) are respectively sealed with the sample (310), and the electrolytic cells (320) are used to set electrolyte, and the electrolyte is respectively in contact with the two side surfaces of the sample (310); the low-resistance adjustable electrolytic cell support (330) is connected to the electrolytic cell assembly and supports the electrolytic cell assembly on the sample (310); An electrochemical workstation (400), the electrochemical workstation (400) being used to cooperate with one of the electrolytic cells (320) and the sample (310) to form an electrochemical detection assembly; A bipolar power supply (500) is used to cooperate with another electrolytic cell (320) and a sample (310) to form a bipolar detection component, and the electrochemical detection component and the bipolar detection component are used to cooperate to test the hydrogen evolution and / or hydrogen diffusion behavior of the sample (310).

2. The electrochemical behavior testing device under bidirectional stress loading according to claim 1, characterized in that: A connecting portion (323) is provided on one side of the electrolytic cell (320) close to the sample (310). The connecting portion (323) is a hollow tubular structure. One end of the connecting portion (323) is fixedly connected to the electrolytic cell (320), and the other end is provided with a connecting inclined surface (325). The connecting inclined surface (325) is used to form an inclined surface matching structure with the sample (310).

3. The electrochemical behavior testing device under bidirectional stress loading according to claim 2, characterized in that: The complementary angle between the connecting inclined surface (325) and the vertical is recorded as α, and the value range of the angle α is 160°-165°.

4. The electrochemical behavior testing device under bidirectional stress loading according to claim 2, characterized in that: A sealing groove (324) is provided on the connecting inclined surface (325), and the sealing groove (324) is used to provide a sealing ring, and the sealing ring is used to improve the sealing effect between the electrolytic cell (320) and the sample (310).

5. The electrochemical behavior testing device under bidirectional stress loading according to claim 2, characterized in that: The specimen (310) is a cross-shaped specimen, comprising two pairs of load-bearing arms arranged in a cross shape, a clamping portion (311) being provided on the load-bearing arms at a position away from the center of the specimen (310), the clamping portion (311) being insulated and used to cooperate with the fixture (200) to clamp the specimen (310), a central thinning portion (313) being provided at the center of the specimen (310), the central thinning portion (313) being thinned relative to the thickness of the load-bearing arms, an inclined transition zone (314) being provided in the circumferential direction of the central thinning portion (313), the inclined transition zone (314) being used to cooperate with the connecting bevel (325) for sealing.

6. The electrochemical behavior testing device under bidirectional stress loading according to claim 5, characterized in that: A plurality of stress relief grooves (312) are provided on each load-bearing arm.

7. The electrochemical behavior testing device under bidirectional stress loading according to claim 5, characterized in that: The thickness of the load-bearing arm of the specimen (310) is recorded as a, the thickness of the central thinning portion (313) is recorded as b, and the width of the inclined transition zone (314) is recorded as c. The value range of c is 0.08a-0.125a, and the value range of b is 2.5a-3.5a.

8. The electrochemical behavior testing device under bidirectional stress loading according to claim 1, characterized in that: The low-resistance adjustable electrolytic cell support (330) includes a drag-reducing sliding ring (337), which is in rolling contact with the sample (310) and is used to convert relative sliding into relative rolling when the low-resistance adjustable electrolytic cell support (330) and the sample (310) move relative to each other.

9. The electrochemical behavior testing device under bidirectional stress loading according to claim 8, characterized in that: The low resistance adjustable electrolytic cell support (330) further comprises a supporting connecting rod (331), a fastening bolt (332), an adjusting screw support block (333), an adjusting screw (334), a connecting rod support ring (335), an adjusting screw adjustment block (336) and a thickness compensation support ring (338), wherein the supporting connecting rods (331) are four in number, and the upper ends of the four supporting connecting rods (331) are connected and fixed in pairs in the front-back direction by fastening bolts (332). 31) are connected by the same spring bolt (340), so that the four supporting links (331) form a V-shaped support structure in the front and rear directions. The link support ring (335) is set between the support links (331) on the front and rear sides. There are three link support rings (335), one of which is set at the lower ends of the four supporting links (331), and the other two are respectively set between the support links (331) at the upper ends of the V-shaped structure. There are two drag reduction sliding rings (337), respectively. The thickness compensation support ring (338) is sleeved on the two connecting rod support rings (335) at the upper end of the V-shaped body. There is at least one pair of thickness compensation support rings (338). The pair of thickness compensation support rings (338) is sleeved on one of the connecting rod support rings (335) at the upper end of the V-shaped body and is arranged on the front and rear sides of the drag reduction sliding ring (337) sleeved on the connecting rod support ring (335). The outer diameter of the thickness compensation support ring (338) is larger than the outer diameter of the drag reduction sliding ring (337) and is used to cooperate with the drag reduction sliding ring (337) to form a The adjusting screw support block (333), the adjusting screw (334) and the adjusting screw adjusting block (336) are used to cooperate to form an adjusting device, and the adjusting device is provided one on each of the front and rear sides of the low-resistance adjustable electrolytic cell support (330), wherein the adjusting screw support block (333) is provided with a blind hole, and the adjusting screw adjusting block (336) is provided with a threaded through hole, and one end of the adjusting screw (334) is threaded through the threaded through hole and then extends into the blind hole.

10. The electrochemical behavior testing device under bidirectional stress loading according to any one of claims 1 to 9, characterized in that: The loading test assembly (300) further comprises a tray (350), the tray (350) being arranged on the lower side of the electrolytic cell assembly, the tray (350) being provided with a through hole, and the lower end of the sample (310) passing through the through hole is clamped by the clamp (200).

11. A method for testing electrochemical behavior under bidirectional stress loading, using the testing device according to any one of claims 1 to 10, characterized in that: The test method includes: Step S1: start the bidirectional loading device and load the fixture; Step S2: Assemble the sample, electrolytic cell, low-resistance adjustable electrolytic cell bracket, and tray, then install them on the fixture and tighten the fixture; Step S3: Adjust the position of the sample and the electrolytic cell to ensure that the center of the chuck of the bidirectional loading device, the center of the sample, and the centers of the two electrolytic cells are in the same position; Step S4: adjusting the bidirectional loading device so that the bidirectional loads are adjusted to preset target values; Step S5: adding electrolyte to the two electrolytic cells; Step S6: inserting electrodes into the electrolytic cells, combining the electrodes of one electrolytic cell with the sample and the electrochemical workstation to form an electrochemical detection assembly, and combining the electrodes of the other electrolytic cell with the sample, a bipolar power supply, and the electrochemical workstation to form a bipolar detection assembly; Step S7: starting the electrochemical workstation, bipolar power supply, and corresponding components in the electrode to perform electrochemical behavior detection according to the electrochemical behavior to be tested; Step S8: After the test is completed, turn off the electrochemical workstation and the bipolar power supply, remove the electrodes, drain the liquid in the electrolytic cell, remove the electrolytic cell and the sample, and end the test.

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