An in-situ measurement system for oxide film rupture strain in high-temperature and high-pressure water environment

Abstract

The present invention discloses an in-situ measurement system for oxide film rupture strain in a high-temperature, high-pressure water environment. The system comprises an autoclave consisting of a body and a cover connected by bolts; the autoclave is provided with a high-temperature, high-pressure, corrosive water environment; a loading unit disposed within the autoclave, comprising an upper loading mechanism and a lower loading mechanism, with a specimen mounting assembly for clamping a tensile specimen disposed between the upper and lower loading mechanisms; the lower loading mechanism extends through the autoclave and is in transmission connection with the tensile mechanism; and a measuring unit comprising an electrochemical workstation for measuring the current and voltage between the tensile specimen and a high-temperature, high-pressure auxiliary electrode, and also for measuring the current and voltage between the tensile specimen and a high-temperature, high-pressure reference electrode. The present invention enables in-situ testing of the mechanical properties of corrosive oxide films.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature corrosion research of metal materials, and in particular to an in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment. Background Art

[0002] Nuclear power reactor structural materials operate in high-temperature, high-pressure, corrosive water environments for extended periods. Structural material failure caused by metal corrosion has long plagued the safe operation of nuclear power plants. In high-temperature, corrosive environments, a continuous oxide film forms on the surface of metal materials. The integrity of this oxide film is a key factor in determining the material's corrosion resistance.

[0003] However, under the influence of complex external loads, the oxide film will rupture, causing the material matrix beneath the film to be exposed to the corrosive medium, causing further corrosion of the matrix material, which may eventually develop into cracks and cause cracking and failure of the structural material.

[0004] Therefore, the protectiveness of the oxide film depends on its mechanical properties, and accurate measurement of the oxide film rupture strain is the basis for evaluating the protectiveness of the oxide film.

[0005] Typically, the oxide film of nuclear power reactor structural materials is thin and adheres to the surface of the metal substrate to form a complex. The environment is a high-temperature, high-pressure, corrosive water environment. Therefore, the measurement technology of the oxide film rupture behavior is very different from that of conventional thin films, making it difficult to accurately measure it in situ.

[0006] For the measurement of the mechanical properties of oxide films on metal surfaces in high-temperature, high-pressure corrosive water environments, existing measurement technologies mainly use non-in-situ characterization methods, that is, a metal sample containing an oxide film is obtained by a corrosion immersion method, and then the metal sample containing the oxide film is removed from the corrosive medium. The stress-strain curve of the oxide film is measured ex-situ in a vacuum or room temperature environment using a micro-cantilever fracture test device or a nanoindentation measurement device, and it is corrected by numerical simulation to finally obtain the rupture stress or strain of the oxide film.

[0007] However, these ex-situ testing methods have many disadvantages: (1) Metal samples containing oxide films need to be removed from the corrosive environment before measurement. During this period, the samples undergo cooling and air exposure, and the physical and chemical properties of the surface oxide film may change, which ultimately affects the mechanical measurement results; (2) The rupture of the surface oxide film of the material during actual service occurs in a high-temperature corrosive water environment. The ex-situ measurement environment is usually room temperature or vacuum environment, which cannot synchronously reflect the rupture behavior of the oxide film in a high-temperature corrosive water environment; (3) The scale of the oxide film is small, and ex-situ measurement methods, such as micro-cantilever fracture test devices and nanoindentation measurement devices, are high-resolution characterization technologies, and the experimental results often rely on the correction of numerical simulations. The overall time and cost costs are high, the technical difficulty is high, and the threshold is high.

[0008] Therefore, there is an urgent need to design and produce an in-situ method and technology suitable for measuring the rupture strain of the oxide film in a high-temperature, high-pressure corrosive water environment. It is hoped that the rupture strain of the oxide film can be accurately measured at a lower cost and measurement threshold to meet the needs of corrosion failure research on reactor structural materials in a high-temperature, high-pressure corrosive water environment. Summary of the Invention

[0009] The purpose of the present invention is to provide an in-situ measurement system for oxide film rupture strain in a high-temperature, high-pressure water environment to solve the problems existing in the prior art, including the inability of the prior art to achieve in-situ measurement in a high-temperature, high-pressure corrosive water environment, high measurement cost, low measurement accuracy, great technical difficulty, and long cycle.

[0010] To achieve the above objectives, the present invention provides the following solution: The present invention provides an in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment, comprising:

[0011] An autoclave consisting of an autoclave body and an autoclave cover connected by bolts; the autoclave is set to a high-temperature, high-pressure, corrosive water environment;

[0012] A loading unit is provided in the autoclave and includes an upper loading mechanism and a lower loading mechanism. A specimen mounting assembly for clamping a tensile specimen is provided between the upper loading mechanism and the lower loading mechanism. The lower loading mechanism passes through the autoclave and is in transmission connection with the tensile mechanism.

[0013] The measuring part includes an electrochemical workstation, which is used to measure the current value and voltage value between the tensile specimen and the high-temperature and high-pressure auxiliary electrode. The electrochemical workstation is also used to measure the current value and voltage value between the tensile specimen and the high-temperature and high-pressure reference electrode.

[0014] Preferably, the upper loading mechanism includes a loading support frame, which is arranged in the autoclave, and a loading upper connecting rod is provided through the top of the loading support frame, the top of the loading upper connecting rod is fixed by a loading upper fastener, and the bottom of the loading upper connecting rod is connected to the top of the sample mounting assembly by a threaded connection.

[0015] Preferably, the lower loading mechanism includes a loading lower stretching rod, which passes through the bottom of the autoclave and is in close contact with the autoclave through a lower stretching rod penetration piece. The top of the loading lower stretching rod is threadedly connected to the bottom of the sample mounting assembly, and the bottom of the loading lower stretching rod passes through the lower stretching rod penetration piece and is fixedly connected to the stretching mechanism.

[0016] Preferably, the stretching mechanism includes a pressure-balancing connecting frame, a pressure-balancing rod connecting head is slidably connected in the pressure-balancing connecting frame, the top of the pressure-balancing connecting frame is threadedly connected to the lower stretching rod through-piece, the bottom of the pressure-balancing connecting frame is threadedly connected to a pressure-balancing lower chamber, a pressure-balancing push rod is arranged through the pressure-balancing lower chamber, the top of the pressure-balancing push rod passes through the pressure-balancing connecting frame and is threadedly connected to the pressure-balancing rod connecting head, the bottom of the loaded lower stretching rod is threadedly connected to the top of the pressure-balancing rod connecting head, the bottom of the pressure-balancing lower chamber is fixedly connected to a servo stretching machine through a stretching machine joint, a plurality of pull rods are circumferentially equidistantly arranged on the top surface of the stretching machine joint, and the pull rods are fixedly connected to the stretching machine joint, and the top of the pull rod extends upward and passes through the pressure-balancing lower chamber and the pressure-balancing connecting frame in sequence and is fixedly connected to the pressure-balancing rod connecting head.

[0017] Preferably, the specimen mounting assembly includes two specimen tensile threaded heads, and the two opposite ends of the two specimen tensile threaded heads are respectively connected to the loading upper connecting rod and the loading lower tensile rod through threads, and the inner walls of the two opposite ends of the two specimen tensile threaded heads are provided with threaded grooves, and the bottom of the thread groove is provided with ceramic insulating gaskets. The two ends of the tensile specimen are respectively abutted against the two ceramic insulating gaskets, and the outer walls of the two ends of the tensile specimen are respectively sleeved with metal clamping heads, and a ceramic insulating ring is provided between the metal clamping head and the tensile specimen, and the end face of the metal clamping head is abutted with a specimen tensile clamping head, and the outer wall of the specimen tensile clamping head is connected to the inner wall of the thread groove through threads.

[0018] Preferably, the high-temperature and high-pressure auxiliary electrode is arranged on the outside of the tensile specimen located between the two specimen tensile pressing heads, the high-temperature and high-pressure auxiliary electrode is electrically connected to one end of the auxiliary electrode wire, and the tensile specimen is electrically connected to one end of the sample wire. The bottom of the high-pressure autoclave is provided with an in-autoclave signal penetration piece, the other ends of the auxiliary electrode wire and the sample wire penetrate the in-autoclave signal penetration piece, the other end of the sample wire is electrically connected to the positive pole of the electrochemical workstation, and the other end of the auxiliary electrode wire is electrically connected to the first negative pole of the electrochemical workstation. The high-temperature and high-pressure reference electrode is arranged at the bottom of the high-pressure autoclave, and the top of the high-temperature and high-pressure reference electrode is located in the high-pressure autoclave. The high-temperature and high-pressure reference electrode is electrically connected to one end of the reference electrode wire, and the other end of the reference electrode wire is electrically connected to the second negative pole of the electrochemical workstation.

[0019] Preferably, the reference electrode wire, the sample wire and the auxiliary electrode wire are all made of pure nickel wire or pure platinum wire, and are all covered with a polytetrafluoroethylene heat shrink tube.

[0020] Preferably, the high-temperature and high-pressure auxiliary electrode is fixed by a positioning fixture, and there is a gap between the high-temperature and high-pressure auxiliary electrode and the tensile specimen, and the gap is constant.

[0021] Preferably, a kettle cover support plate is provided on the outer wall of the kettle cover.

[0022] Preferably, the bottom of the autoclave is provided with water inlet and outlet pipe penetrations.

[0023] The present invention discloses the following technical effects: the present invention can directly perform in-situ stretching on the combination of the tensile specimen and the oxide film after the oxide film is generated, without changing the environment and morphology of the oxide film, to study the rupture behavior of the oxide film under actual service conditions. Zirconia ceramics are used to insulate the tensile specimen and the loading fixture, allowing the rupture behavior of the oxide film to be monitored by electrochemical measurements. With the help of an electrochemical workstation and a high-temperature and high-pressure auxiliary electrode system, the time of oxide film rupture can be accurately determined by in-situ corrosion current monitoring. The deformation of the oxide film on the surface of the gauge section of the tensile specimen before and after the oxide film rupture is recorded by a displacement sensor, and the rupture strain value of the oxide film can be calculated simply, quickly and directly. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work.

[0025] Figure 1 Schematic diagram of the structure of the in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment of the present invention;

[0026] Figure 2 This is a schematic structural diagram of the sample installation assembly in the present invention;

[0027] Among them, 1. Sample installation assembly; 2-1. Kettle body; 2-2. Kettle cover; 2-3. Kettle cover support plate; 3-1. Loading upper fastener; 3-2. Loading upper connecting rod; 3-3. Loading lower tensile rod; 3-4. Loading support frame; 4-1. Inlet and outlet pipe penetrations; 4-2. Kettle internal signal penetrations; 4-3. High temperature and high pressure reference electrode; 5-1. Lower tensile rod penetration; 5-2. Pressure balance connection frame; 5-3. Pressure balance rod connector; 5-4. Pressure Balance push rod; 5-5, pressure balance lower chamber; 5-6, tensile machine connector; 5-7, servo tensile machine; 6-1, reference electrode wire; 6-2, electrochemical workstation; 7, tensile specimen; 8, specimen wire; 9, high-temperature and high-pressure auxiliary electrode; 10, auxiliary electrode wire; 11, positioning fixture; 12, metal clamping head; 13-1, ceramic insulating ring; 13-2, ceramic insulating gasket; 14-1, specimen tensile clamping head; 14-2, specimen tensile threaded head. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0030] Reference Figure 1-2 The present invention provides an in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment, comprising:

[0031] The autoclave is composed of an autoclave body 2-1 and an autoclave cover 2-2 connected by bolts; the autoclave is set to a high-temperature and high-pressure corrosive water environment;

[0032] The loading part is arranged in the autoclave and includes an upper loading mechanism and a lower loading mechanism. A sample mounting assembly 1 for clamping the tensile sample 7 is arranged between the upper loading mechanism and the lower loading mechanism; the lower loading mechanism passes through the autoclave and is transmission-connected to the tensile mechanism;

[0033] The measuring section includes an electrochemical workstation 6-2, which is used to measure the current value and voltage value between the tensile specimen and the high-temperature and high-pressure auxiliary electrode 9. The electrochemical workstation 6-2 is also used to measure the current value and voltage value between the tensile specimen 7 and the high-temperature and high-pressure reference electrode 4-3.

[0034] The present invention can directly perform in-situ stretching on the combination of the tensile specimen 7 and the oxide film after the oxide film is generated, without changing the environment and morphology of the oxide film, to study the rupture behavior of the oxide film under actual service conditions. Zirconia ceramics are used to insulate the tensile specimen 7 from the loading fixture, allowing the rupture behavior of the oxide film to be monitored by electrochemical measurements. With the help of the electrochemical workstation 6-2 and the high-temperature and high-pressure auxiliary electrode system, the time of oxide film rupture can be accurately determined by in-situ corrosion current monitoring. The deformation of the oxide film on the surface of the gauge section of the tensile specimen 7 before and after the oxide film rupture is recorded by a displacement sensor, and the rupture strain value of the oxide film is calculated simply, quickly and directly.

[0035] In the present invention, the high-pressure autoclave is compressed and sealed by bolts to ensure sealing and avoid leakage.

[0036] To further optimize the solution, the upper loading mechanism includes a loading support frame 3-4, which is arranged in the autoclave, and a loading upper connecting rod 3-2 is provided through the top of the loading support frame 3-4, and the top of the loading upper connecting rod 3-2 is fixed by a loading upper fastener 3-1, and the bottom of the loading upper connecting rod 3-2 is connected to the top of the sample mounting assembly 1 by a threaded connection.

[0037] To further optimize the solution, the lower loading mechanism includes a loading lower stretching rod 3-3, which passes through the bottom of the autoclave and is in close contact with the autoclave through the lower stretching rod penetration piece 5-1. The top of the loading lower stretching rod 3-3 is threadedly connected to the bottom of the sample mounting assembly 1, and the bottom of the loading lower stretching rod 3-3 passes through the lower stretching rod penetration piece 5-1 and is fixed to the stretching mechanism.

[0038] The upper loading mechanism and the lower loading mechanism can achieve a fixing effect on the sample mounting assembly 1 .

[0039] The lower stretching penetration piece can seal the loaded lower stretching rod 3 - 3 , and the loaded lower stretching rod 3 - 3 can be connected to the stretching mechanism, thereby achieving a stretching effect on the tensile specimen 7 .

[0040] Further optimization scheme, the stretching mechanism includes a pressure balancing connection frame 5-2, the pressure balancing connection frame 5-2 is slidably connected with a pressure balancing rod connector 5-3, the top of the pressure balancing connection frame 5-2 is connected to the lower stretching rod through-piece 5-1 by a thread, the bottom of the pressure balancing connection frame 5-2 is connected to a pressure balancing lower chamber 5-5 by a thread, the pressure balancing lower chamber 5-5 is penetrated by a pressure balancing push rod 5-4, the top of the pressure balancing push rod 5-4 penetrates the pressure balancing connection frame 5-2 and is connected to the pressure balancing rod The connecting head 5-3 is connected by threads, and the bottom of the loaded stretching rod 3-3 is connected to the top of the pressure balance rod connecting head 5-3 by threads. The bottom of the pressure balance lower chamber 5-5 is fixedly connected to the servo stretching machine 5-7 through the stretching machine joint 5-6. A number of pull rods are arranged at equal intervals around the top surface of the stretching machine joint 5-6, and the pull rods are fixedly connected to the stretching machine joint 5-6. The top of the pull rod extends upward and passes through the pressure balance lower chamber 5-5 and the pressure balance connecting frame 5-2 in turn, and is fixedly connected to the pressure balance rod connecting head 5-3.

[0041] A further optimized solution is provided, in which the specimen mounting assembly 1 includes two specimen tensile threaded heads 14-2, and the two opposite ends of the two specimen tensile threaded heads 14-2 are respectively connected to the loading upper connecting rod 3-2 and the loading lower tensile rod 3-3 by threads. The inner walls of the two opposite ends of the two specimen tensile threaded heads 14-2 are provided with threaded grooves, and the bottom of the threaded grooves is provided with ceramic insulating gaskets 13-2. The two ends of the tensile specimen 7 are respectively abutted against the two ceramic insulating gaskets 13-2, and the outer walls of the two ends of the tensile specimen 7 are respectively sleeved with metal clamping heads 12, and a ceramic insulating ring 13-1 is provided between the metal clamping head 12 and the tensile specimen 7. The end face of the metal clamping head 12 is abutted against the specimen tensile clamping head 14-1, and the outer wall of the specimen tensile clamping head 14-1 is connected to the inner wall of the threaded groove by threads.

[0042] The set tensile specimen 7 is isolated from the metal pressing head 12 and the specimen tensile threaded head 14-2 by using a ceramic insulating gasket 13-2 and a ceramic insulating ring 13-1, which can avoid galvanic corrosion caused by direct contact.

[0043] To further optimize the solution, the high-temperature and high-pressure auxiliary electrode 9 is arranged on the outside of the tensile sample 7 located between the two sample tensile pressing heads 14-1, the high-temperature and high-pressure auxiliary electrode 9 is electrically connected to one end of the auxiliary electrode wire 10, and the tensile sample 7 is electrically connected to one end of the sample wire 8. The bottom of the autoclave is provided with an in-autoclave signal penetration piece 4-2, the other ends of the auxiliary electrode wire 10 and the sample wire 8 penetrate the in-autoclave signal penetration piece 4-2, the other end of the sample wire 8 is electrically connected to the positive pole of the electrochemical workstation 6-2, and the other end of the auxiliary electrode wire 10 is electrically connected to the first negative pole of the electrochemical workstation 6-2. The high-temperature and high-pressure reference electrode 4-3 is arranged at the bottom of the autoclave, and the top of the high-temperature and high-pressure reference electrode 4-3 is located in the autoclave, the high-temperature and high-pressure reference electrode 4-3 is electrically connected to one end of the reference electrode wire 6-1, and the other end of the reference electrode wire 6-1 is electrically connected to the second negative pole of the electrochemical workstation 6-2.

[0044] To further optimize the solution, the reference electrode wire 6-1, the sample wire 8 and the auxiliary electrode wire 10 are all made of pure nickel wire or pure platinum wire, and the reference electrode wire 6-1, the sample wire 8 and the auxiliary electrode wire 10 are all covered with polytetrafluoroethylene heat shrink tubing.

[0045] The insulation inside the autoclave can be ensured by covering the wire with PTFE heat shrink tubing.

[0046] In a further optimized solution, the high-temperature and high-pressure auxiliary electrode 9 is fixed by a positioning fixture 11 , and there is a constant gap between the high-temperature and high-pressure auxiliary electrode 9 and the tensile specimen 7 .

[0047] According to a further optimized solution, a kettle cover support plate 2-3 is provided on the outer wall of the kettle cover 2-2.

[0048] To further optimize the solution, a water inlet and outlet pipe penetration piece 4-1 is provided at the bottom of the autoclave.

[0049] The measurement process of the present invention is as follows:

[0050] Measure the gauge length of tensile specimen 7 and record it as L0;

[0051] Before closing the kettle body 2-1 and the kettle cover 2-2, the tensile specimen 7 is mounted on the specimen mounting assembly 1 and then mounted on the loading support frame 3-4 in the kettle body 2-1 and connected to the loaded lower tensile rod 3-3. A certain pre-tightening force is applied to the tensile specimen 7 through the private service tensile machine to ensure that the tensile specimen 7 is vertical and centered.

[0052] During the connection process, the tensile specimen 7 is insulated by the ceramic insulating spacer 13-2 and the ceramic insulating ring 13-1;

[0053] Subsequently, a pure nickel wire or pure platinum wire is welded to the bottom (non-gauge length section) of the tensile specimen 7, and a layer of polytetrafluoroethylene heat shrink tubing is coated on the outside of the wire to form a specimen wire 8; a pure nickel wire or pure platinum wire is welded to the high-temperature and high-pressure auxiliary electrode 9, and the outside of the wire is also coated with a layer of polytetrafluoroethylene heat shrink tubing to form an auxiliary electrode wire 10; a high-temperature and high-pressure reference electrode 4-3 is set and connected to the reference electrode wire 6-1;

[0054] Install the high-temperature and high-pressure auxiliary electrode 9 and its positioning fixture 11 (the positioning fixture 11 is prior art and will not be described in detail here). Adjust the position of the high-temperature and high-pressure auxiliary electrode 9 so that it is as close as possible to the surface of the gauge section of the tensile specimen 7, but avoid direct contact.

[0055] Close the autoclave body 2-1 and the autoclave cover 2-2 to ensure sealing, and then introduce an aqueous solution of about 50% of the autoclave volume into the autoclave through the water inlet and outlet pipe penetration piece 4-1 on the autoclave. The choice of solution is determined according to the actual working environment;

[0056] Gas is introduced into the autoclave for dissolved oxygen / dissolved hydrogen control, and then heating is started to the target temperature and pressure;

[0057] After the temperature and pressure stabilize, start timing and simultaneously turn on the electrochemical workstation 6-2 to record the current and voltage between the tensile specimen 7 and the high-temperature and high-pressure auxiliary electrode 9, and the current and voltage between the high-temperature and high-pressure reference electrode 4-3 and the tensile specimen 7, while waiting for the formation of an oxide film on the surface of the tensile specimen 7;

[0058] As the oxide film on the surface of the tensile specimen 7 grows, the current and voltage between the tensile specimen 7 and the high-temperature and high-pressure auxiliary electrode 9 begin to slowly decrease. When they reach a stable state or the decreasing rate is very slow, it indicates that the oxide film on the surface of the tensile specimen 7 has gradually stabilized and loading can be started.

[0059] After the oxide film growth is complete, the servo stretcher 5-7 is set to begin loading. Simultaneously, the load applied to the tensile specimen 7 and the deformation of the tensile specimen 7 are recorded in real time using a displacement sensor and a force sensor. The position of the displacement sensor at this time is recorded as L1. During this period, the loading rate should not be too fast, and the changes in the current and voltage between the tensile specimen 7 and the high-temperature and high-pressure auxiliary electrode 9 are recorded and observed in real time.

[0060] When the oxide film breaks and the base metal begins to be exposed, a sudden increase in the current value between the tensile specimen 7 and the high-temperature and high-pressure auxiliary electrode 9 should be observed. The position of the displacement sensor at this time is recorded as L2.

[0061] After the measurement is completed, the tensile specimen 7 is unloaded, the temperature and pressure are lowered, the autoclave is opened, the tensile specimen 7 is taken out, and the rupture of the oxide film is determined by observation under a microscope.

[0062] The oxide film rupture strain is calculated according to the formula:

[0063] (ε):ε=(L2-L1) / L0.

[0064] The present invention can directly measure the rupture effect of the oxide film in a high-temperature and high-pressure corrosion environment without removing the tensile specimen 7 containing the oxide film, thereby eliminating the interference of external factors to the greatest extent and improving the precision and accuracy of the measurement; the measurement method is not limited by the size and shape of the tensile specimen 7, and can measure the oxide film rupture strain of tensile specimens 7 of various types and sizes; the measurement method is not limited by the corrosion environment, and can measure the oxide film rupture strain value under different corrosion environments in situ; the measurement method determines the time of oxide film rupture by measuring the change of corrosion current, and only needs to consider the relative change of corrosion current and ignore the measurement accuracy, so the measurement accuracy requirement for the electrochemical workstation 6-2 is relatively low; the measurement device and system are simple in design, and the measurement accuracy of the oxide film rupture strain is high, fast and low.

[0065] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0066] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment, characterized in that: include: A high-pressure autoclave is composed of an autoclave body (2-1) and an autoclave cover (2-2) connected by bolts; the autoclave is provided with a high-temperature and high-pressure corrosive water environment; A loading part is provided in the autoclave, the loading part comprises an upper loading mechanism and a lower loading mechanism, a sample mounting assembly (1) for clamping a tensile sample (7) is provided between the upper loading mechanism and the lower loading mechanism; the lower loading mechanism passes through the autoclave and is in transmission connection with the tensile mechanism; A measuring section, comprising an electrochemical workstation (6-2), the electrochemical workstation (6-2) being used to measure a current value and a voltage value between the tensile specimen and a high-temperature and high-pressure auxiliary electrode (9), and the electrochemical workstation (6-2) being further used to measure a current value and a voltage value between the tensile specimen (7) and a high-temperature and high-pressure reference electrode (4-3); The sample mounting assembly (1) comprises two sample tensile thread heads (14-2), the inner walls of the two opposite ends of the two sample tensile thread heads (14-2) are both provided with thread grooves, the bottoms of the thread grooves are provided with ceramic insulating gaskets (13-2), the two ends of the tensile sample (7) are respectively in contact with the two ceramic insulating gaskets (13-2), the outer walls of the two ends of the tensile sample (7) are respectively provided with metal pressing heads (12), and a ceramic insulating ring (13-1) is provided between the metal pressing head (12) and the tensile sample (7); The high-temperature and high-pressure auxiliary electrode (9) is fixed by a positioning fixture (11), and a gap exists between the high-temperature and high-pressure auxiliary electrode (9) and the tensile specimen (7), and the gap is constant.

2. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 1, characterized in that: The upper loading mechanism comprises a loading support frame (3-4), the loading support frame (3-4) is arranged in the autoclave, a loading upper connecting rod (3-2) is provided through the top of the loading support frame (3-4), the top of the loading upper connecting rod (3-2) is fixed by a loading upper fastener (3-1), and the bottom of the loading upper connecting rod (3-2) is connected to the top of the sample mounting assembly (1) by a thread.

3. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 2, characterized in that: The lower loading mechanism comprises a loading lower stretching rod (3-3), the loading lower stretching rod (3-3) passes through the bottom of the autoclave, and the loading lower stretching rod (3-3) is in close contact with the autoclave through a lower stretching rod penetration piece (5-1), the top of the loading lower stretching rod (3-3) is connected to the bottom of the sample mounting assembly (1) through a threaded connection, and the bottom of the loading lower stretching rod (3-3) passes through the lower stretching rod penetration piece (5-1) and is fixedly connected to the stretching mechanism.

4. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 3, characterized in that: The stretching mechanism comprises a pressure balancing connection frame (5-2), a pressure balancing rod connector (5-3) is slidably connected in the pressure balancing connection frame (5-2), the top of the pressure balancing connection frame (5-2) is connected to the lower stretching rod through-piece (5-1) through a thread, the bottom of the pressure balancing connection frame (5-2) is connected to a pressure balancing lower chamber (5-5) through a thread, a pressure balancing push rod (5-4) is provided through the pressure balancing lower chamber (5-5), the top of the pressure balancing push rod (5-4) passes through the pressure balancing connection frame (5-2) and is connected to the pressure balancing rod connector (5-1). -3) is connected by threads, the bottom of the loaded lower stretching rod (3-3) is connected to the top of the pressure balance rod connector (5-3) by threads, the bottom of the pressure balance lower chamber (5-5) is fixedly connected to the servo stretching machine (5-7) through the stretching machine joint (5-6), and a plurality of pull rods are arranged at equal intervals in the circumferential direction on the top surface of the stretching machine joint (5-6), and the pull rods are fixedly connected to the stretching machine joint (5-6), and the top of the pull rod extends upward and passes through the pressure balance lower chamber (5-5) and the pressure balance connection frame (5-2) in sequence, and is then fixedly connected to the pressure balance rod connector (5-3).

5. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 4, characterized in that: The two opposite ends of the two sample tensile threaded heads (14-2) are respectively connected to the loading upper connecting rod (3-2) and the loading lower tensile rod (3-3) through threads, and the end surface of the metal pressing head (12) is abutted with a sample tensile pressing head (14-1), and the outer wall of the sample tensile pressing head (14-1) is connected to the inner wall of the thread groove through threads.

6. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 5, characterized in that: The high temperature and high pressure auxiliary electrode (9) is arranged outside the tensile specimen (7) between the two specimen tensile pressing heads (14-1), the high temperature and high pressure auxiliary electrode (9) is electrically connected to one end of the auxiliary electrode wire (10), the tensile specimen (7) is electrically connected to one end of the specimen wire (8), the bottom of the autoclave is provided with an in-autoclave signal penetration piece (4-2), the auxiliary electrode wire (10) and the other end of the specimen wire (8) penetrate the in-autoclave signal penetration piece (4-2), the other end of the specimen wire (8) is electrically connected to the in-autoclave signal penetration piece (4-2), and the other end of the specimen wire (8) is electrically connected to the in-autoclave signal penetration piece (4-2). The high-temperature and high-pressure reference electrode (4-3) is electrically connected to the positive electrode of the electrochemical workstation (6-2), the other end of the auxiliary electrode wire (10) is electrically connected to the first negative electrode of the electrochemical workstation (6-2), the high-temperature and high-pressure reference electrode (4-3) is arranged at the bottom of the autoclave, and the top of the high-temperature and high-pressure reference electrode (4-3) is located in the autoclave, the high-temperature and high-pressure reference electrode (4-3) is electrically connected to one end of the reference electrode wire (6-1), and the other end of the reference electrode wire (6-1) is electrically connected to the second negative electrode of the electrochemical workstation (6-2).

7. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 6, characterized in that: The reference electrode wire (6-1), the sample wire (8) and the auxiliary electrode wire (10) are all made of pure nickel wire or pure platinum wire, and the reference electrode wire (6-1), the sample wire (8) and the auxiliary electrode wire (10) are all covered with a polytetrafluoroethylene heat shrink tube.

8. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 7, characterized in that: A kettle cover supporting plate (2-3) is provided on the outer wall of the kettle cover (2-2).

9. The in-situ measurement system for oxide film rupture strain in a high-temperature and high-pressure water environment according to claim 8, characterized in that: The bottom of the autoclave is provided with water inlet and outlet pipe penetration pieces (4-1).

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