An in-situ stress corrosion monitoring system and method

Abstract

The application relates to an in-situ stress corrosion monitoring system and a monitoring method, which comprises a stress measuring component, an electrochemical measuring component, a stress corrosion component and a control component. The electrochemical measuring component is used for placing a working electrode therein in the stress corrosion component and providing an electrochemical environment for the stress corrosion component; the stress corrosion component is used for corroding the working electrode under the electrochemical environment; the stress measuring component is used for stress testing of the corroded working electrode; and the control component is connected with the stress measuring component, the electrochemical measuring component and the stress corrosion component respectively and is used for controlling the work of the components. In the application, the test area is reduced through a slit, the test area is smaller than the crack width, the test precision of the stress corrosion cracking position is improved, and the X-ray focusing before the stress testing is timely carried out through the length-adjustable clamp base, so that the test speed is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of stress and static load stress corrosion detection, and particularly relates to an in-situ stress corrosion monitoring system and a monitoring method. BACKGROUND

[0002] Stress corrosion refers to the damage behavior of a material under tensile stress in a corrosive medium. Under the action of a corrosive medium, corrosion pits are often formed on the surface of the material, and at the same time, cracks are often formed at the bottom of the corrosion pits under the action of an external load, leading to stress corrosion cracking. This often causes major safety accidents such as bridge collapse, airplane crash, and pipeline leakage. Stress corrosion often has no premonition, and once it occurs, the crack propagation rate is fast, and the stress causing damage is much smaller than the yield stress. Stress corrosion behavior is generally closely related to the loading force, loading time, and the material's own structure. Although a large number of researchers have carried out relevant research on stress corrosion behavior, the position, time, and process of stress corrosion cracking need to be further explored.

[0003] As the name implies, stress corrosion has some relationship with stress. Although the strain gauge method can measure surface stress, the strain gauge will corrode in a corrosive environment, thereby affecting the measurement results, so the non-contact stress detection technology is more suitable for this condition. X-ray diffraction technology is a material analysis and detection technology that can calculate the stress size by comparing the difference between the stress-free Debye ring and the deformed Debye ring under stress. However, there is currently no in-situ device and method for stress corrosion research. In addition, single electrochemical in-situ testing has been applied to the study of stress corrosion and its cracking behavior. Patent No. CN202410623959.4 discloses a stress corrosion sample preparation device and method for electrochemical testing, which can realize in-situ electrochemical testing during stress corrosion. Patent No. CN201910480721.X discloses an online monitoring device and analysis method for stress corrosion cracking based on electrochemical noise, which can distinguish different stages of stress corrosion crack propagation by different types of current / potential noise peaks. However, single electrochemical in-situ detection cannot determine the position of stress corrosion cracking and subsequent stress release. In order to further explore the stress corrosion cracking behavior, there is an urgent need for a device that can be used for stress corrosion research with multiple in-situ detection functions. SUMMARY

[0004] In order to overcome the above-mentioned problems existing in the prior art, the present application provides an in-situ stress corrosion monitoring system and a monitoring method, which are used to solve the above-mentioned problems existing in the prior art.

[0005] An in-situ stress corrosion monitoring system, the system comprising: a stress measurement assembly, an electrochemical measurement assembly, a stress corrosion assembly, and a control assembly,

[0006] The electrochemical measurement component is used to place the working electrode therein into the stress corrosion component and provide an electrochemical environment for the stress corrosion component;

[0007] The stress corrosion component is used to corrode the working electrode under the electrochemical environment;

[0008] The stress measurement component is used to test the stress of the corroded working electrode;

[0009] The control component is connected with the stress measurement component, the electrochemical measurement component and the stress corrosion component respectively, and is used to control the working of each component.

[0010] According to the aspect and any possible implementation manner as described above, an implementation manner is further provided, wherein the stress measurement component comprises an X-ray stress tester, a slit connected with the X-ray stress tester and a mechanical arm, and the mechanical arm is used to adjust the height and angle of the X-ray stress tester and the slit.

[0011] According to the aspect and any possible implementation manner as described above, an implementation manner is further provided, wherein the stress corrosion component comprises a corrosion container, a stress corrosion clamp arranged in the corrosion container, a positioning block, a main bolt, an auxiliary bolt and a clamp base; one end of the main bolt and the auxiliary bolt is connected with the stress corrosion clamp, the other end of the main bolt and the auxiliary bolt is connected with the positioning block arranged in the stress corrosion clamp, and one end of the clamp base is connected with the stress corrosion clamp and the other end of the clamp base is fixed on the corrosion container.

[0012] According to the aspect and any possible implementation manner as described above, an implementation manner is further provided, wherein the electrochemical measurement component comprises a ring platinum electrode, a reference electrode, a working electrode and an electrochemical workstation; the ring platinum electrode and the reference electrode are arranged inside the cavity of the corrosion container and are connected with the electrochemical workstation through wires; the working electrode is fixed between the stress corrosion clamp and the positioning block and is connected with the electrochemical workstation.

[0013] According to the aspect and any possible implementation manner as described above, an implementation manner is further provided, wherein the ring platinum electrode is arranged between the slit and the working electrode, the center hole diameter of the ring platinum electrode is 1-10 mm, and the width of the slit is 0.05-0.1 mm.

[0014] According to the aspect and any possible implementation manner as described above, an implementation manner is further provided, wherein the control component is a computer, and the system further comprises a motion platform connected with the computer, and the motion platform is arranged at the bottom of the corrosion container.

[0015] As the aspect and any possible implementation manner described above further provide an implementation manner, the stress corrosion assembly further comprises four ceramic rods, two outer ceramic rods are connected with the four-point bending fixture through a key connection manner, two inner ceramic rods are connected with the positioning block through a key connection manner, and the inner and outer ceramic rods are in contact with the working electrode on the other side.

[0016] As the aspect and any possible implementation manner described above further provide an implementation manner, the mechanical arm comprises a motor and a reducer, and the control assembly controls the motor and the reducer, so that the mechanical arm can perform reciprocating motion in horizontal, vertical and perpendicular directions, and the motion speed is 0.1 mm / s to 0.5 mm / s, so as to adjust the positions of the X-ray stress tester and the slit.

[0017] The application also provides a monitoring method of an in-situ stress corrosion monitoring system, and the method is implemented by using the system and comprises the following steps: (1) fixing the working electrode by using the stress corrosion fixture, the positioning block and the ceramic rods, adjusting the working electrode to be horizontal in an unloaded state by using auxiliary bolts, loading stress by using main bolts, selecting a fixture base with a corresponding length according to the loading force, connecting the stress corrosion fixture with the corrosion container, and pouring the corrosion solution into the corrosion container;

[0018] (2) placing the ring platinum electrode above the stress loading area of the working electrode, placing the reference electrode in the cavity of the corrosion container, turning on the computer and the X-ray stress tester, adjusting the positions of the motion platform, the angle and the height of the mechanical arm, so that the X-ray is emitted from the slit and the center hole of the ring platinum electrode to the to-be-tested area, and ensuring that the X-ray diffraction line is emitted from the center hole of the ring platinum electrode and is received by the X-ray stress tester;

[0019] (3) pouring the corrosion solution into the corrosion container, so that the liquid level of the corrosion solution is higher than the center area of the working electrode by a certain height, turning on the power supply of the electrochemical workstation, so that the corrosion solution, the reference electrode, the ring platinum electrode and the working electrode form a path and undergo an oxidation-reduction reaction, starting stress and electrochemical impedance testing, and the computer receives the electrical signals of the X-ray stress tester, the mechanical arm, the electrochemical workstation and the motion platform to output the cracking position and time, the stress distribution cloud diagram and the stress and impedance spectrum curves changing with time.

[0020] As the aspect and any possible implementation manner described above further provide an implementation manner, the certain height is 0.1 mm to 2 mm.

[0021] Advantages of the application

[0022] (1) The application is simple to operate and does not damage the surface of the material; and the device is suitable for different types of stress corrosion fixtures;

[0023] (2) the present application through the slit to reduce its test area, so that the test area is less than the crack width, thereby improving the test accuracy of stress corrosion cracking position; through the length adjustable clamp base, in time before the stress test X-ray focusing, improve the test speed;

[0024] (3) the present application by obtaining the stress distribution nephogram of loading area, so as to judge the position and cracking time of stress corrosion cracking, and also can obtain the in-situ variation curve of surface stress and electrochemical impedance spectrum with time in the process of stress corrosion. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 the overall structure of the device for in-situ monitoring of surface stress and corrosion resistance in the process of stress corrosion;

[0026] Figure 2 the device part structure section view.

[0027] The marks in the figure are: 1-X-ray stress tester, 2-slit, 3-mechanical arm, 4-ring platinum electrode, 5-reference electrode, 6-working electrode, 7-electrochemical workstation, 8-four-point bending clamp, 9-positioning block, 10-ceramic rod, 11-main bolt, 12-assistant bolt, 13-main thread, 14-assistant thread, 15-through hole thread, 16-clamp base, 17-corrosion container, 18-computer, 19-motion platform. DETAILED DESCRIPTION

[0028] In order to better understand the technical scheme of the present application, the content of the present application includes but is not limited to the specific embodiments in the following, similar technologies and methods should be regarded as the scope of protection of the present application. In order to make the technical problems, technical schemes and advantages solved by the present application more clear, the following will be described in detail in combination with the drawings and specific embodiments.

[0029] It should be clear that the embodiments described in the present application are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0030] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "said" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0031] The present application provides an in-situ stress corrosion monitoring system, the system comprises: stress measurement component, electrochemical measurement component, stress corrosion component and control component,

[0032] the electrochemical measurement component is used to place the working electrode therein into the stress corrosion component and to provide an electrochemical environment for the stress corrosion component;

[0033] the stress corrosion component is used to corrode the working electrode under the electrochemical environment;

[0034] the stress measurement component is used to test the stress of the corroded working electrode;

[0035] the control component is connected with the stress measurement component, the electrochemical measurement component and the stress corrosion component respectively, and is used to control the work of each component.

[0036] Specifically, as shown in Figure 1 The in-situ stress corrosion monitoring system comprises a stress measurement component, an electrochemical measurement component, a stress corrosion component and a control component, and the control component is realized by using a computer 18.

[0037] The stress measurement component comprises an X-ray stress tester 1, a slit 2 and a mechanical arm 3, the slit 2 is tightly connected with the X-ray stress tester 1 by any one of welding, mortise and tenon connection and bolt connection, the slit 2 is used to narrow the test area, so that the test range is smaller than the crack width, so as to determine the stress corrosion cracking position, the inside of the slit is a rectangle, if the slit width is too large so that the test area is larger than the crack width, it will lead to the failure to accurately determine the position of crack initiation, therefore, the slit width is selected to be 0.05mm-0.1mm, and the corresponding slit width is selected according to the type of the test material. The mechanical arm 3 comprises a motor and a speed reducer, and is connected with the computer 18, the computer 18 controls the motor and the speed reducer so that the mechanical arm 3 can reciprocate in the horizontal, vertical and perpendicular directions, the motion speed range is 0.1mm / s-0.5mm / s, which satisfies the three-dimensional motion of the X-ray stress tester 1 and the slit 2, and facilitates the parameter debugging work in the early stage of stress test. The X-ray stress tester 1 can realize surface stress detection, and has the characteristics of fast test speed, high portability and high sensitivity, the test speed range is 2min / point-4min / point. The X-ray stress tester 1 and the electrochemical workstation 7 are connected with the computer 18;

[0038] The stress corrosion component comprises a corrosion stress clamp, a positioning block 9, a ceramic rod 10, a main bolt 11, an auxiliary bolt 12, a main thread 13, an auxiliary thread 14, a through-hole thread 15, a clamp base 16 and a corrosion container 17, wherein the corrosion stress clamp adopts different loading modes such as a three-point bending clamp, a four-point bending clamp and a U-bending clamp according to the needs, and the four-point bending clamp 8 is preferably adopted in the present application; as shown in Figure 2 One end of the main bolt 11 is connected with the clamp base 16 through the through-hole thread 15, and the other end of the main bolt 11 is connected with the ceramic rod 10 through the main thread 13. Figure 2The middle unmarked is connected with the four-point bending fixture 8, one end of the auxiliary bolt 12 is also connected with the four-point bending fixture 8 through the through hole thread 15, the other end of the main bolt 11 is connected with the positioning block 9 through the main thread 13, the main bolt 11 is used for stress loading, the other end of the auxiliary bolt 12 is connected with the positioning block 9 through the auxiliary thread 14, the surface deflection change amount of the working electrode is calculated by the loading force size, the auxiliary bolt 12 is used for adjusting the working electrode 6 to keep horizontal in the unloading state, so as to reduce the uneven stress distribution phenomenon generated in the stress loading process, and the stress loading is carried out through the main bolt 11; the fixture base 16 is connected with the four-point bending fixture 8 in any mode of bolt connection and welding, the fixture base 16 is preferably connected in the mode of thread, and the fixture base 16 is connected with the corrosion container 17 in the mode of thread. The length specification of the fixture base 16 can be replaced according to different loading forces of the working electrode 6, and the length range of the fixture base 16 is 10mm-80mm. When the loading force of the working electrode 6 is large, a shorter fixture base 16 needs to be replaced, and when the loading force is small, a longer fixture base 16 needs to be replaced, so as to timely adjust the height difference between the test point of the working electrode 6 and the liquid level of the corrosion solution under the premise that the X-ray stress tester 1 is not moved during stress testing, for rapid focusing of the X-ray, and improving the testing precision. The ceramic rods 10 include a plurality of rods, and four rods are arranged in the application. The outer ceramic rods 10 arranged on the outer side are connected with the four-point bending fixture 8 through key connection, the inner ceramic rods 10 arranged on the inner side are connected with the positioning block 9 through key connection, and the inner and outer ceramic rods 10 are in contact with the working electrode 6, that is, the outer ceramic rods 10 arranged on the outer side are located above the end of the working electrode 6, and the inner ceramic rods 10 arranged on the inner side adjacent to the outer ceramic rods 10 are arranged below the working electrode 6.

[0039] The stress corrosion assembly further comprises a motion platform 19, the motion platform 19 comprises a driving motor, the motion platform 19 is connected with the computer 18, and the motion platform 19 is connected with the bottom of the corrosion container 17 through any connection mode of welding or thread, and is used for driving the corrosion container to move. The computer 18 controls the motor to make the motion platform 19 and the corrosion container 17 reciprocate in the horizontal and vertical directions at a step speed of 0.5mm / s-1mm / s, so as to realize stress testing in the horizontal and vertical directions.

[0040] The electrochemical measurement assembly includes a ring-shaped platinum electrode 4, a reference electrode 5, a working electrode 6, and an electrochemical workstation 7. The ring-shaped platinum electrode 4 and the reference electrode 5 serve as cathodes and anodes, respectively, to generate redox reactions. The working electrode 6 undergoes corrosion. The reference electrode 5 controls the electrode potential of the working electrode 6. The electrochemical workstation 7 is used for power-on and parameter control. The ring-shaped platinum electrode 4 and the reference electrode 5 are located inside the cavity of the corrosion container 17 and are connected to the electrochemical workstation 7 through wires. The working electrode 6 is fixed by a four-point bending clamp 8, a positioning block 9, and a ceramic rod 10. The working electrode 6 is connected to the wires by any connection method such as welding or threading and is connected to the electrochemical workstation 7. The upper surface of the working electrode 6 is reserved for 1 cm 2 ~ 3 cm 2 electrochemical measurement. The other parts, such as the welding points, are evenly coated by any method such as silicone coating or spraying to prevent the metal in other parts from being exposed to the corrosion solution and affecting the test results. The outer ceramic rod 10 is connected to the four-point bending clamp 8 by a key connection method. The inner ceramic rod 10 is connected to the positioning block 9 by a key connection method. The other side of the inner and outer ceramic rods 10 contacts the working electrode 6. One end of the computer 18 is connected to the X-ray stress tester 1 through wires, and the other end is connected to the electrochemical workstation 7 through wires. The electrochemical workstation 7 is used for power-on and parameter control. The ring-shaped platinum electrode 4 is located inside the cavity of the corrosion container 17 and is between the slit 2 and the working electrode 6. The incident and diffracted X-rays pass through the central hole of the ring-shaped platinum electrode 4, thereby achieving in-situ detection. The diameter of the central hole of the ring-shaped platinum electrode 4 should be determined according to the different materials of the working electrode 6 and the test crystal planes of different metals to satisfy the condition that the maximum width of the diffraction cone is less than the diameter of the central hole of the ring-shaped platinum electrode 4. The diameter of the central hole is 1 mm to 10 mm. The working electrode 6 is a cuboid with a thickness of 0.5 mm to 25 mm. The material of the working electrode 6 is steel or aluminum alloy. The length and width of the cuboid are 20 mm and 5 mm, respectively. The thickness is 1 mm or 10 mm. For specific descriptions, please refer to the following examples.

[0041] The computer 18 is used to turn on the X-ray stress tester 1, the mechanical arm 3, the electrochemical workstation 7, and the motion platform 19, control the sliding distance of the motion platform 19, the angle and height of the mechanical arm 3, transmit and identify the test results of the X-ray stress tester 1, and output the stress distribution cloud map on the computer 18. The software of the computer 18 converts and processes the electrical signals of the X-ray stress tester 1, the mechanical arm 3, the electrochemical workstation 7, and the motion platform 19, and finally converts them into the curves of the in-situ output stress and impedance spectrum with time from the initial stage of stress corrosion to the process of stress corrosion cracking.

[0042] Preferably, the system of the present application further comprises a software system loaded in the computer 18, which software system includes but is not limited to the control of the system signal acquisition, data storage, processing and analysis, motion platform displacement control and the output of the analysis results, etc.

[0043] As an embodiment disclosed by the present application, the present application discloses a monitoring method of an in-situ stress corrosion monitoring system, which is realized by using the system of the present application and includes the following steps:

[0044] (1) The working electrode 6 is fixed by using the four-point bending clamp 8, the positioning block 9 and the inner and outer ceramic rods 10, the working electrode 6 is adjusted by the auxiliary bolt 12 to keep horizontal in the unloaded state, the clamp base 16 of the corresponding length specification is selected according to the pre-set loading force size, and the four-point bending clamp 8 is connected with the corrosion container 17;

[0045] Wherein, the working electrode 6 is stress-loaded by the main bolt 11, the maximum elastic stress of the working electrode 6 in the loading process appears in the middle part of the working electrode, the maximum deflection of the working electrode 6 corresponding to different loading forces is calculated according to the loading stress calculation formula, and the loading stress and the maximum deflection satisfy the calculation formula as follows:

[0046]

[0047] In the formula, σ max is the maximum elastic stress of the middle part of the working electrode 6, is the quantity to be solved, y is the maximum deflection of the working electrode 6, the maximum deflection value is a known quantity, E is the elastic modulus, the elastic modulus is a known quantity, t is the thickness of the working electrode, H is the spacing between the two outermost outer ceramic rods, and A is the spacing between the two innermost inner ceramic rods.

[0048] (2) The ring-shaped platinum electrode 4 is placed directly above the stress loading area of the working electrode 6, the reference electrode 5 is placed inside the cavity of the corrosion container 17, the computer 18 and the X-ray stress tester 1 are turned on, the position of the motion platform 19, the angle and height of the mechanical arm 3 are adjusted, the X-rays emitted by the X-ray stress tester 1 are shot into the stress loading area from the slit 2 and the center hole of the ring-shaped platinum electrode 4, and it is ensured that the X-ray diffraction lines are shot out of the center hole of the ring-shaped platinum electrode 4 and are received by the X-ray stress tester 1, the X-ray diffraction lines are used for stress calculation by the X-ray stress tester 1, and the calculation results are sent to the computer 18 by the X-ray stress tester 1;

[0049] (3) Pour the corrosion solution into the corrosion container 17, so that the corrosion solution liquid level is higher than the center region of the working electrode 6 by 0.1 mm to 2 mm, turn on the power supply of the electrochemical workstation 7, so that the corrosion solution, the reference electrode 5, the ring platinum electrode 4 and the working electrode 6 form a channel and a redox reaction occurs, the stress and electrochemical impedance test is started, and the computer 18 receives the electrical signals of the X-ray stress tester 1, the mechanical arm 3, the electrochemical workstation 7 and the motion platform 19 to output the cracking position and time, the stress distribution cloud map and the stress and impedance spectrum curve with time.

[0050] Further, the method for judging the cracking position and cracking time: first, the stress test is performed on the stress loading region of the working electrode, the computer 18 controls the motor to make the motion platform 19 reciprocate in the horizontal and vertical directions, and the step speed satisfies 0.5 mm / s to 1 mm / s, so that the stress test in the horizontal and vertical directions is realized, the calculation result is transmitted to the computer 18 by the X-ray stress tester 1, and the software in the computer 18 automatically calculates the stress value. Subsequently, the software in the computer 18 records the initial stress value after loading, which is measured by the X-ray stress tester 1 and monitored in situ during the loading process, and the software in the computer 18 judges whether cracking occurs according to the stress value at the corresponding position (>±20 MPa), and finally outputs the stress distribution cloud map to judge the cracking position and cracking time. The test under other loading stresses is performed by the stress relaxation of the working electrode 6 through the main bolt 11, the working electrode 6 is removed and replaced, and steps (1)-(3) are repeated. The following is described in combination with specific embodiments.

[0051] Example 1

[0052] The cuboid sample with a length, width and thickness of 20 mm, 5 mm and 1 mm respectively is used as the working electrode 6, which is subjected to 300 MPa stress loading through the four-point bending clamp 8, and the slit width is 0.1 mm. The stress corrosion cracking time and position are judged, and the stress and impedance spectrum curve during the stress corrosion cracking process is measured.

[0053] (1) Calculate the deflection change amount of the surface of the working electrode 6 corresponding to the preset loading stress of 300 MPa, load the stress on the working electrode 6 through the main bolt 11, the height of the clamp base 16 is 50 mm, connect the four-point bending clamp with the corrosion container 17, pour 3.5 wt.% NaCl corrosion solution into the corrosion container 17, and the corrosion solution liquid level is higher than the center region of the working electrode 6 by 0.5 mm;

[0054] (2) Put the ring platinum electrode 4 above the working electrode 6 and the stress loading area, and put the reference electrode 5 inside the cavity of the corrosion container 17. Turn on the computer 18 and the X-ray stress tester 1, adjust the position of the motion platform 19, adjust the height and angle of the mechanical arm 3, so that the X-ray is emitted from the slit 2 and the center hole of the ring platinum electrode 4 to the area to be tested, and ensure that the X-ray diffraction line is emitted from the center hole of the ring platinum electrode 4 and received by the X-ray stress tester;

[0055] (3) Turn on the electrochemical workstation and start the stress and electrochemical impedance test. The computer software identifies the cracking position (2 mm from the center line) and the time (375 h). The stress distribution cloud chart and the stress and impedance spectrum curves over time are output on the computer 18.

[0056] Example 2

[0057] The cuboid sample with a length, width and thickness of 20 mm, 5 mm and 1 mm respectively is used as the working electrode 6. The stress loading is performed by the four-point bending clamp 8 at 200 MPa, and the slit width is 0.08 mm. The stress corrosion cracking time and position are determined, and the stress and impedance spectrum curves during stress corrosion cracking are measured.

[0058] (1) Calculate the deflection change of the working electrode 6 surface corresponding to the preset loading stress of 200 MPa. The stress loading is performed on the working electrode 6 by the main bolt 11, the clamp base 16 height is 50 mm, the four-bending clamp is connected with the corrosion container 17, and the 3.5 wt.% NaCl corrosion solution is poured into the corrosion container 17;

[0059] (2) Put the ring platinum electrode 4 above the working electrode 6 and the stress loading area, and put the reference electrode 5 inside the cavity of the corrosion container 17. Turn on the computer 18 and the X-ray stress tester 1, adjust the position of the motion platform 19, adjust the height and angle of the mechanical arm 3, so that the X-ray is emitted from the slit 2 and the center hole of the ring platinum electrode 4 to the area to be tested, and ensure that the X-ray diffraction line is emitted from the center hole of the ring platinum electrode 4 and received by the X-ray stress tester;

[0060] (3) Turn on the electrochemical workstation and start the stress and electrochemical impedance test. The computer software identifies the cracking position (2 mm from the center line) and the time (375 h). The stress distribution cloud chart and the stress and impedance spectrum curves over time are output on the computer 18.

[0061] Example 3

[0062] A cuboid sample of aluminum alloy material with a length, width and thickness of 20 mm, 5 mm and 1 mm, respectively, is used as the working electrode 6, and is subjected to a stress loading of 100 MPa by the four-point bending clamp 8 with a slit width of 0.05 mm. The stress corrosion cracking time and its position are determined, and the stress and impedance spectrum change curves during stress corrosion cracking are measured.

[0063] (1) The deflection change amount of the surface of the working electrode 6 corresponding to the preset loading stress of 100 MPa is calculated, the working electrode 6 is subjected to stress loading by the main bolt 11, the height of the clamp base 16 is 60 mm, the four-bending clamp is connected to the corrosion container 17, and 3.5 wt.% NaCl corrosion solution is poured into the corrosion container 17, with the corrosion solution level being 0.5 mm higher than the center region of the working electrode 6;

[0064] (2) The annular platinum electrode 4 is placed directly above the working electrode 6 and the stress loading region, and the reference electrode 5 is placed inside the cavity of the corrosion container 17. The computer 18 and the X-ray stress tester 1 are turned on, the position of the motion platform 19 is adjusted, the height and angle of the mechanical arm 3 are adjusted, the X-ray is made to enter the to-be-tested region from the slit 2 and the center hole of the annular platinum electrode 4, and it is ensured that the X-ray diffraction line is emitted from the center hole of the annular platinum electrode 4 and is received by the X-ray stress tester;

[0065] (3) The electrochemical workstation is turned on, and the stress and electrochemical impedance test is started. The computer software identifies the cracking position (1.9 mm from the center line) and the time (98 h), and outputs the stress distribution cloud chart, the stress and impedance spectrum change curves over time on the computer 18.

[0066] Example 4

[0067] A cuboid sample of aluminum alloy material with a length, width and thickness of 20 mm, 5 mm and 10 mm, respectively, is used as the working electrode 6, and is subjected to a stress loading of 200 MPa by the four-point bending clamp 8 with a slit width of 0.08 mm. The stress corrosion cracking time and its position are determined, and the stress and impedance spectrum change curves during stress corrosion cracking are measured.

[0068] (1) The deflection change amount of the surface of the working electrode 6 corresponding to the preset loading stress of 200 MPa is calculated, the working electrode 6 is subjected to stress loading by the main bolt 11, the height of the clamp base 16 is 45 mm, the four-bending clamp is connected to the corrosion container 17, and 3.5 wt.% NaCl corrosion solution is poured into the corrosion container 17, with the corrosion solution level being 0.5 mm higher than the center region of the working electrode 6;

[0069] (2) Put the ring platinum electrode 4 above the working electrode 6 and the stress loading area, and put the reference electrode 5 inside the cavity of the corrosion container 17. Turn on the computer 18 and the X-ray stress tester 1, adjust the position of the motion platform 19, adjust the height and angle of the mechanical arm 3, so that the X-ray is emitted from the slit 2 and the center hole of the ring platinum electrode 4 to the area to be tested, and ensure that the X-ray diffraction line is emitted from the center hole of the ring platinum electrode 4 and received by the X-ray stress tester;

[0070] (3) Turn on the electrochemical workstation and start the stress and electrochemical impedance test. The computer software identifies the cracking position (0.8 mm from the center line) and the time (105 h). The stress distribution cloud chart and the stress and impedance spectrum curves with time are output on the computer 18.

[0071] Example 5

[0072] The cuboid sample with aluminum alloy material, length, width and thickness of 20 mm, 5 mm and 1 mm respectively is used as the working electrode 6. The stress loading is performed by the three-point bending clamp at 200 MPa, and the slit width is 0.08 mm. The stress corrosion cracking time and position are judged, and the stress and impedance spectrum curves during the stress corrosion cracking process are measured.

[0073] (1) Calculate the deflection change of the working electrode 6 surface corresponding to the preset loading stress 200 MPa, load the stress on the working electrode 6 by the main bolt 11, the height of the clamp base 16 is 50 mm, and the four bending clamps are connected with the corrosion container 17. Pour 5.0wt.% NaCl corrosion solution into the corrosion container 17;

[0074] (2) Put the ring platinum electrode 4 above the working electrode 6 and the stress loading area, and put the reference electrode 5 inside the cavity of the corrosion container 17. Turn on the computer 18 and the X-ray stress tester 1, adjust the position of the motion platform 19, adjust the height and angle of the mechanical arm 3, so that the X-ray is emitted from the slit 2 and the center hole of the ring platinum electrode 4 to the area to be tested, and ensure that the X-ray diffraction line is emitted from the center hole of the ring platinum electrode 4 and received by the X-ray stress tester;

[0075] (3) Turn on the electrochemical workstation and start the stress and electrochemical impedance test. The computer software identifies the cracking position (0.8 mm from the center line) and the time (105 h). The stress distribution cloud chart and the stress and impedance spectrum curves with time are output on the computer 18.

[0076] The foregoing description illustrates and describes several preferred embodiments of the present application, but it is to be understood that the application is not limited to the above-described forms, and that it should not be seen as excluding other embodiments, but rather as being applicable in a variety of other combinations, modifications and environments, and capable of being altered in various ways within the scope of the application as described in the claims, by the teaching or knowledge of the relevant art, or by the common general knowledge. Any alterations and further modifications in the application made by a person of ordinary skill in the art are to be construed as being within the scope of the application as defined in the appended claims.

Claims

1. An in-situ stress corrosion monitoring system, characterized by, The system comprises a stress measurement component, an electrochemical measurement component, a stress corrosion component and a control component, The electrochemical measurement component is used for placing a working electrode therein in the stress corrosion component and providing an electrochemical environment for the stress corrosion component, and the electrochemical measurement component comprises a ring platinum electrode, a reference electrode, a working electrode and an electrochemical workstation. The stress corrosion component is used for corroding the working electrode under the electrochemical environment, and the stress corrosion component comprises a corrosion container and a stress corrosion clamp, a positioning block, a main bolt, an auxiliary bolt, a clamp base and ceramic rods arranged in the corrosion container. The stress measurement component is used for stress testing of the corroded working electrode, and the stress measurement component comprises an X-ray stress tester and a slit and a mechanical arm connected thereto, the mechanical arm is used for adjusting the height and angle of the X-ray stress tester and the slit, so that X-rays are emitted from the slit to the center hole of the ring platinum electrode and then to the testing area, the slit is used for narrowing the testing area, so that the testing range is smaller than the crack width, so as to determine the stress corrosion cracking position, the ring platinum electrode is arranged between the slit and the working electrode, and the width of the slit is 0.05-0.1 mm. The control component is connected with the stress measurement component, the electrochemical measurement component and the stress corrosion component respectively, and is used for controlling the working of each component.

2. The in-situ stress corrosion monitoring system of claim 1, wherein, One end of the main bolt and the auxiliary bolt is connected with the stress corrosion clamp, and the other end of the main bolt and the auxiliary bolt is connected with the positioning block arranged in the stress corrosion clamp, one end of the clamp base is connected with the stress corrosion clamp, and the other end is fixed on the corrosion container.

3. The in-situ stress corrosion monitoring system of claim 2, wherein, The ring platinum electrode and the reference electrode are arranged inside the cavity of the corrosion container and are connected with the electrochemical workstation through wires; the working electrode is fixed between the stress corrosion clamp and the positioning block and is connected with the electrochemical workstation.

4. The in-situ stress corrosion monitoring system of claim 1, wherein, The center hole diameter of the ring platinum electrode is 1-10 mm.

5. The in-situ stress corrosion monitoring system of claim 1, wherein, The control component is a computer, and the system further comprises a motion platform connected with the computer, and the motion platform is arranged at the bottom of the corrosion container.

6. The in-situ stress corrosion monitoring system of claim 1, wherein, The ceramic rods are four, the stress corrosion clamp is a four-point bending clamp, two outer ceramic rods are connected with the four-point bending clamp through a key connection mode, two inner ceramic rods are connected with the positioning block through a key connection mode, and the other sides of the inner and outer ceramic rods are in contact with the working electrode.

7. The in-situ stress corrosion monitoring system of claim 1, wherein, The mechanical arm comprises a motor and a reducer, and the control component controls the motor and the reducer, so that the mechanical arm can reciprocate in the horizontal, vertical and perpendicular directions, and the motion speed is 0.1 mm / s-0.5 mm / s, so as to adjust the positions of the X-ray stress tester and the slit.

8. A monitoring method of an in-situ stress corrosion monitoring system, characterized by, The method is implemented by using the system of any one of claims 1-7, comprising: (1) fixing the working electrode by using a stress corrosion clamp, a positioning block and a ceramic rod, adjusting the working electrode by using auxiliary bolts to keep it horizontal in an unloaded state, loading stress by using main bolts, selecting a clamp base with a corresponding length according to the loading force, connecting the stress corrosion clamp with the corrosion container, and pouring the corrosion solution into the corrosion container; (2) placing the ring-shaped platinum electrode above the stress loading area of the working electrode and the reference electrode inside the cavity of the corrosion container, turning on the computer and the X-ray stress tester, adjusting the position of the motion platform, the angle and height of the mechanical arm, so that the X-ray is shot from the slit and the center hole of the ring-shaped platinum electrode to the test area, and the X-ray diffraction line is shot from the center hole of the ring-shaped platinum electrode and received by the X-ray stress tester; (3) pouring the corrosion solution into the corrosion container so that the liquid level of the corrosion solution is higher than the center area of the working electrode by a certain height, turning on the power supply of the electrochemical workstation, so that the corrosion solution, the reference electrode, the ring-shaped platinum electrode and the working electrode form a path and undergo oxidation-reduction reaction, starting stress and electrochemical impedance test, and the computer receives the electrical signals of the X-ray stress tester, the mechanical arm, the electrochemical workstation and the motion platform to output the cracking position and time, the stress distribution cloud picture and the stress and impedance spectrum curve with time.

9. The monitoring method of the in-situ stress corrosion monitoring system according to claim 8, characterized in that, The certain height is 0.1mm-2mm.

Images