In-situ testing device and method for high-pressure gas-phase hydrogen-induced lattice distortion

Abstract

The present invention discloses an in-situ testing device and an in-situ testing method for high-pressure gas-phase hydrogen-induced lattice distortion, which relates to the technical field of hydrogen-induced lattice distortion testing. The device comprises: an X-ray diffractometer and a high-pressure container; the high-pressure container is a non-enclosed cavity structure, the test sample is placed in the non-enclosed cavity of the high-pressure container, and forms a closure for the non-enclosed cavity; the air inlet of the high-pressure container is used to input gas into the non-enclosed cavity of the high-pressure container; the side of the test sample away from the non-enclosed cavity is used as the test surface; the X-ray diffractometer is used to emit X-rays to the test surface and receive diffraction signals. The present invention can simulate different hydrogen pressures, in-situ measure the degree of hydrogen-induced lattice distortion caused by the high-pressure hydrogen penetration process, thereby evaluating the degree of hydrogen damage, i.e., hydrogen embrittlement, of metal materials in a high-pressure hydrogen environment. Compared with the off-situ testing method, the in-situ testing method of the present invention has a higher accuracy.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogen-induced lattice distortion testing, in particular to an in-situ testing device and an in-situ testing method for high-pressure gas-phase hydrogen-induced lattice distortion. Background Art

[0002] Metal hydrogen embrittlement refers to the phenomenon that the mechanical properties such as ductility and toughness decrease or even cause damage or cracking due to the presence of atomic hydrogen in the metal. According to the source of hydrogen, metal hydrogen embrittlement is usually divided into internal hydrogen embrittlement and environmental hydrogen embrittlement. Environmental hydrogen embrittlement involves the situation where the metal material is exposed to a high-pressure hydrogen environment. Regardless of the form of hydrogen embrittlement, it is related to the interaction between hydrogen atoms and metal materials. After hydrogen atoms enter the metal material, they are located in the gap position in the metal lattice, causing the lattice to be distorted and the lattice constant to change, which in turn causes the lattice spacing to change. Although a lot of research has been carried out on the behavior and mechanism of metal hydrogen embrittlement at home and abroad, there are few studies on the testing technology for metal hydrogen embrittlement. It is difficult to detect the early hydrogen embrittlement of components in a non-destructive way and determine the possibility of further damage by existing technical means. From the above, it can be seen that if the change in lattice spacing can be obtained through certain testing methods, the lattice distortion effect of hydrogen atoms on metal materials can be clarified. Therefore, it is urgent to develop a non-contact, non-destructive testing device and testing method for metal hydrogen embrittlement, so as to effectively control the risk of hydrogen embrittlement of components. Summary of the invention

[0003] In order to overcome the defects in the above-mentioned prior art, the present invention provides an in-situ high-pressure gas-phase hydrogen-induced lattice distortion testing device, which can simulate different hydrogen pressures of metal materials used in high-pressure hydrogen storage and transportation equipment, and can also in-situ measure the degree of hydrogen-induced lattice distortion caused by the high-pressure hydrogen penetration process, thereby evaluating the degree of hydrogen damage to metal materials in a high-pressure hydrogen environment.

[0004] To achieve the above object, the present invention adopts the following technical solutions, including:

[0005] A high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing device, the device comprising: an X-ray diffractometer, a high-pressure container;

[0006] The high-pressure container is a non-enclosed cavity structure for placing the test sample; the test sample is placed in the non-enclosed cavity of the high-pressure container, and forms a seal for the non-enclosed cavity;

[0007] The air inlet of the high-pressure container is connected to an air inlet pipeline for inputting gas into the non-enclosed cavity of the high-pressure container;

[0008] A side of the test sample away from the non-enclosed cavity is used as a test surface; the X-ray diffractometer is used to emit X-rays to the test surface and receive diffraction signals.

[0009] Preferably, the gas outlet of the high-pressure container is connected to a gas outlet pipeline for discharging the gas in the non-enclosed cavity of the high-pressure container;

[0010] A booster device, a third control valve and a third pressure gauge are sequentially arranged on the air intake pipeline along the gas transmission direction; the booster device is used to boost the gas;

[0011] A fourth control valve and a vacuum pump are sequentially arranged on the gas outlet pipeline along the gas transmission direction; the vacuum pump is used to extract the gas.

[0012] Preferably, the air inlet of the high-pressure container is connected to the nitrogen cylinder and the hydrogen cylinder respectively through an air inlet pipeline, so as to input nitrogen / hydrogen into the non-enclosed cavity of the high-pressure container; a second control valve and a second pressure gauge are provided at the output port of the nitrogen cylinder; a first control valve and a first pressure gauge are provided at the output port of the hydrogen cylinder.

[0013] Preferably, the test specimen is in the shape of a boss, including a raised portion and a platform portion; the raised portion is placed in a non-enclosed cavity, and the shape of the non-enclosed cavity is adapted to that of the raised portion; the platform portion is located above the high-pressure container to achieve sealing of the non-enclosed cavity.

[0014] Preferably, a sealing groove is provided on the upper surface of the high-pressure container; a sealing ring is placed in the sealing groove for contacting the test sample to prevent the gas in the non-enclosed cavity from escaping.

[0015] Preferably, after the test sample is placed in the non-enclosed cavity, a flange cover is placed on the test sample, and the flange cover is connected to the high-pressure container by bolts to compress the test sample.

[0016] The present invention also provides a high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing method, which is applied to the above-mentioned high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing device, characterized in that the method comprises the following steps:

[0017] Step 1, processing the metal material into a test specimen;

[0018] Step 2: placing the test sample in the non-enclosed cavity of the high-pressure container to form a seal for the non-enclosed cavity;

[0019] Step 3: input high-pressure inert gas of a set pressure into the non-enclosed cavity of the high-pressure container, use an X-ray diffractometer to emit X-rays to the test surface of the test sample and receive diffraction signals, perform X-ray diffraction analysis, and obtain the corresponding diffraction angle 2θ0, thereby calculating the lattice spacing d0 of the test sample before hydrogen filling, d0=λ / 2sinθ0, λ is the wavelength of the X-ray;

[0020] Step 4: input high-pressure hydrogen gas of a set pressure into the non-enclosed cavity of the high-pressure container, use an X-ray diffractometer to emit X-rays to the test surface of the test sample, receive diffraction signals, perform X-ray diffraction analysis, and obtain the corresponding diffraction angle 2θ0', thereby calculating the lattice spacing d0' of the test sample after hydrogen filling, d0'=λ / 2sinθ0';

[0021] Step 5, calculating the degree of hydrogen-induced lattice distortion ε0=(d0'-d0) / d0 of the metal material under the high-pressure gas-phase hydrogen charging condition.

[0022] The present invention also provides a high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing method, which is applied to the above-mentioned high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing device. The specific process of the method is as follows:

[0023] S1, processing the metal material into a test specimen, grinding and polishing the test surface of the test specimen, selecting a test point on the test surface, and marking the test direction of the test point;

[0024] S2, cleaning the test device;

[0025] S3, placing the test sample in the non-enclosed cavity of the high-pressure container to form a seal for the non-enclosed cavity;

[0026] S4, close the second control valve and the first control valve, open the third control valve and the fourth control valve, and turn on the vacuum pump to start vacuuming until the reading on the third pressure gauge reaches the vacuum pressure P1, and then close the fourth control valve and the vacuum pump in turn;

[0027] S5, open the second control valve and adjust the pressure at the outlet of the nitrogen bottle to the purge pressure P2, until the reading of the third pressure gauge reaches the purge pressure P2, close the third control valve, open the fourth control valve, and discharge the nitrogen; after the reading of the third pressure gauge returns to the atmospheric pressure P3, close the fourth control valve;

[0028] S6, repeat step S5 several times;

[0029] S7, turning on the X-ray diffractometer, and adjusting the measuring direction of the X-ray diffractometer to be consistent with the measuring direction of the test point;

[0030] S8, close the fourth control valve, open the second control valve and the third control valve, turn on the booster to start boosting, until the reading on the third pressure gauge reaches the set pressure, i.e., the test pressure P4, then close the third control valve, the booster, and the second control valve in sequence;

[0031] S9, determining the radiation line and diffraction crystal plane {hkl} of the X-ray diffractometer according to the type of the metal material, and determining the wavelength λ of the incident X-rays, using the X-ray diffractometer to emit X-rays to the test surface and receive diffraction signals, performing X-ray diffraction analysis, obtaining the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determining the corresponding diffraction angle 2θ0; according to the Bragg law, calculating the lattice spacing d0 of the metal material before hydrogen filling, d0=λ / 2sinθ0;

[0032] S10, open the fourth control valve to discharge nitrogen, and after the reading of the third pressure gauge returns to the atmospheric pressure P3, close the fourth control valve;

[0033] S11, open the first control valve and the third control valve, adjust the pressure at the outlet of the hydrogen cylinder to the purge pressure P2, close the third control valve until the reading of the third pressure gauge reaches the purge pressure P2, open the fourth control valve, and discharge the hydrogen; after the reading of the third pressure gauge returns to the atmospheric pressure P3, close the fourth control valve;

[0034] S12, repeat step S11 several times;

[0035] S13, close the fourth control valve, open the second control valve and the first control valve, turn on the booster to start boosting, until the reading on the third pressure gauge reaches the set pressure, i.e., the test pressure P4, then close the third control valve, the booster and the first control valve in sequence;

[0036] S14, maintaining the hydrogen pressure in the high pressure container at the test pressure P4 until time t is reached;

[0037] The time t is the time required for hydrogen to penetrate the test surface of the test sample;

[0038] S15, using an X-ray diffractometer to emit X-rays to the test surface and receive diffraction signals, performing X-ray diffraction analysis, obtaining the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determining the corresponding diffraction angle 2θ0'; according to the Bragg law, calculating the lattice spacing d0' of the metal material after hydrogenation, d0'=λ / 2sinθ0';

[0039] S16, calculate the degree of hydrogen-induced lattice distortion of metal materials under the high-pressure gas phase hydrogen charging condition of the test pressure P4

[0040] ε0=(d0'-d0) / d0.

[0041] The advantages of the present invention are:

[0042] (1) The present invention provides an in-situ testing device for high-pressure gas-phase hydrogen-induced lattice distortion, which can simulate different hydrogen pressures of metal materials used in high-pressure hydrogen storage and transportation equipment, and can also in-situ measure the degree of hydrogen-induced lattice distortion caused by the high-pressure hydrogen penetration process, thereby evaluating the degree of hydrogen damage to metal materials in a high-pressure hydrogen environment.

[0043] (2) Compared with the off-site test method, the present invention can ensure that the test position and test direction of the sample before and after hydrogen filling are completely consistent. For the off-site test process, the position and direction are first marked on the test surface of the sample, and then measurements are performed before and after hydrogen filling to obtain hydrogen-induced lattice distortion. However, after hydrogen filling, the sample needs to be repositioned when performing the X-ray diffraction test so that the test position and test direction are as consistent as possible with those before hydrogen filling, but this is almost impossible to do in actual operation, and this slight deviation may bring about huge changes, resulting in large errors in the test results, and then obtaining wrong conclusions.

[0044] (3) Compared with the off-site test method, the present invention can ensure that the sample tested after hydrogen filling is in a saturated hydrogen concentration state. In the off-site test process, hydrogen pressure relief, device disassembly, sample removal, and calibration and sample placement during the X-ray diffraction test are required after hydrogen filling. This series of processes takes at least 1 hour. For test conditions with higher hydrogen pressure, the disassembly process is more complicated, resulting in a longer process. For materials with ferrite structure, the hydrogen diffusion coefficient is very large. During the off-site test preparation process, hydrogen will overflow from the surface of the material, causing the hydrogen concentration to drop sharply, which in turn causes the hydrogen concentration on the surface of the material during the test to be much lower than the hydrogen concentration on the surface of the material after hydrogen filling, resulting in a large error in the test results, and thus obtaining an erroneous conclusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of an in-situ testing device for high-pressure gas-phase hydrogen-induced lattice distortion.

[0046] Figure 2 AA cross-section schematic diagram of the high-pressure vessel.

[0047] Figure 3 A top view of the high pressure vessel.

[0048] Description of reference numerals:

[0049] 1-X-ray diffractometer, 2-high pressure container, 3-test sample, 4-flange cover, 5-bolt, 6-air outlet pipe, 7-air inlet pipe, 8-fourth control valve, 9-vacuum pump, 10-third pressure gauge, 11-third control valve, 12-boosting device, 13-second control valve, 14-second pressure gauge, 15-first control valve, 16-first pressure gauge, 17-sealing ring, 21-air port. DETAILED DESCRIPTION

[0050] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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 creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] like Figure 1 As shown, the present invention provides an in-situ testing device for high-pressure gas-phase hydrogen-induced lattice distortion, comprising: an X-ray diffractometer (XRD) 1, a high-pressure container 2, a flange cover 4, bolts 5, an air inlet pipeline 7, an air outlet pipeline 6, a vacuum pump 9, a pressurizing device 12, a nitrogen cylinder, and a hydrogen cylinder.

[0053] The high pressure container 2 is a non-enclosed cavity structure; the non-enclosed cavity is used to place the test sample 3, the test sample 3 is placed in the non-enclosed cavity, and forms a seal for the non-enclosed cavity. The side of the test sample 3 facing the non-enclosed cavity is the inner surface, and the side of the test sample 3 away from the non-enclosed cavity is the outer surface and serves as the test surface.

[0054] The air inlet of the high-pressure container 2 is connected to the nitrogen bottle and the hydrogen bottle respectively through the air inlet pipeline 7, and the nitrogen bottle / hydrogen bottle inputs nitrogen / hydrogen into the non-enclosed cavity of the high-pressure container 2, that is, inputs nitrogen / hydrogen into the inner surface of the test sample 3, and the air outlet of the high-pressure container 2 discharges the gas to the outside through the air outlet pipeline 6. In this embodiment, the air inlet and the air outlet of the high-pressure container 2 are the same air port 21.

[0055] The air intake pipeline 7 is provided with a booster device 12, a third control valve 11 and a third pressure gauge 10 in sequence along the gas transmission direction; the booster device 12 is used to boost the gas pressure to the required test pressure.

[0056] The gas outlet pipeline 6 is provided with a fourth control valve 8 and a vacuum pump 9 in sequence along the gas transmission direction; the vacuum pump 9 is used to extract the gas.

[0057] The outlet of the nitrogen cylinder is provided with a second control valve 13 and a second pressure gauge 14. The outlet of the hydrogen cylinder is provided with a first control valve 15 and a first pressure gauge 16.

[0058] like Figure 2 and Figure 3As shown, in this embodiment, the test sample 3 is in the shape of a boss, including a convex portion and a platform portion, and the radial dimension of the platform portion is greater than the radial dimension of the convex portion. The non-enclosed cavity of the high-pressure container 2 is adapted to the shape of the convex portion of the test sample, the convex portion is placed in the non-enclosed cavity, and the platform portion of the test sample 3 is located above the high-pressure container 2 to achieve the closure of the non-enclosed cavity.

[0059] A sealing groove is provided on the upper surface of the high pressure container 2, and a sealing ring 17 is placed in the sealing groove to contact the platform portion of the test sample 3 to prevent the gas in the non-enclosed cavity from escaping.

[0060] The flange cover 4 is placed on the test sample 3 and connected to the high pressure container 2 via bolts 5 to compress the test sample 3 .

[0061] The outer surface of the test sample 3, that is, the side of the platform away from the non-enclosed cavity, is used as the test surface. The X-ray diffractometer 1 emits X-rays to the test surface and receives diffraction signals to measure the diffraction peak of the test sample 3.

[0062] Example 2

[0063] Using the above-mentioned in-situ testing device, the present invention provides an in-situ testing method for high-pressure gas-phase hydrogen-induced lattice distortion, comprising the following steps:

[0064] Step 1, processing the metal material into a test sample 3;

[0065] Step 2: placing the test sample 3 in the non-enclosed cavity of the high-pressure container 2 to form a seal for the non-enclosed cavity;

[0066] Step 3: input high-pressure inert gas of a set pressure into the non-enclosed cavity of the high-pressure container 2, use the X-ray diffractometer 1 to emit X-rays to the test surface of the test sample 3 and receive diffraction signals, perform X-ray diffraction analysis, and obtain the corresponding diffraction angle 2θ0, thereby calculating the lattice spacing d0 of the test sample 3 before hydrogen filling, d0=λ / 2sinθ0, λ is the wavelength of the X-ray;

[0067] Step 4: input high-pressure hydrogen of a set pressure into the non-enclosed cavity of the high-pressure container 2, use the X-ray diffractometer 1 to emit X-rays to the test surface of the test sample 3 and receive diffraction signals, perform X-ray diffraction analysis, and obtain the corresponding diffraction angle 2θ0', thereby calculating the lattice spacing d0' of the test sample 3 after hydrogen filling, d0'=λ / 2sinθ0';

[0068] Step 5, calculating the degree of hydrogen-induced lattice distortion ε0=(d0'-d0) / d0 of the metal material under the high-pressure gas phase hydrogen charging condition.

[0069] Example 3

[0070] The present invention also provides an in-situ testing method for high-pressure gas-phase hydrogen-induced lattice distortion, which uses the above-mentioned in-situ testing device to measure the hydrogen embrittlement degree of metal materials used in high-pressure hydrogen storage and transportation equipment under different hydrogen pressures, comprising the following steps:

[0071] S1, process the metal material of the high-pressure hydrogen storage and transportation equipment into the test sample 3. Grind the test surface of the test sample 3 to ensure that the test surface roughness is less than 10μm, and there is no thick oxide layer, additional stress layer, dirt, oil film, and vibrate polish the test surface to eliminate the machining stress. Select the test point M on the test surface and mark the test direction of the test point M.

[0072] S2, cleaning the test device, including: cleaning the sealing ring 17, and blowing the surface of the sealing ring 17 with dry gas to ensure the cleanliness of the sealing ring 17; cleaning the inner surface of the high-pressure container 2 (i.e., the surface of the non-enclosed cavity), and the contact surface between the test sample 3 and the flange cover 4, and blowing with dry gas to ensure cleanliness.

[0073] S3, place the sealing ring 17 in the sealing groove of the high-pressure container 2, and place the test sample 3 in the non-enclosed cavity of the high-pressure container, place the flange cover 4 on the test sample 3, locate the horizontal position of the flange cover 4 through the bolt holes of the flange cover 4 and the high-pressure container 2, and install and tighten the bolts 5 in sequence along the diagonal line.

[0074] S4, close the first control valve 15 and the second control valve 13, open the third control valve 11 and the fourth control valve 8, and turn on the vacuum pump 9 to start vacuuming until the reading of the third pressure gauge 10 reaches the vacuum pressure P1, and then close the fourth control valve 8 and the vacuum pump 9 in turn.

[0075] S5, open the second control valve 13, adjust the second control valve 13 according to the indication of the second pressure gauge 14 so that the pressure at the outlet of the nitrogen bottle is the purge pressure P2, until the indication of the third pressure gauge 10 reaches the purge pressure P2, close the third control valve 11, open the fourth control valve 8, and discharge the nitrogen; after the indication of the third pressure gauge 10 returns to the atmospheric pressure P3, close the fourth control valve 8.

[0076] S6, repeat step S5 several times to make the purity of nitrogen in the high-pressure container 2 reach 99.999%.

[0077] S7, turning on the X-ray diffractometer 1, and adjusting the measuring direction of the X-ray diffractometer 1 to be consistent with the measuring direction marked on the test sample.

[0078] S8, close the fourth control valve 8, open the second control valve 13 and the third control valve 11, adjust the second control valve 13 according to the indication of the second pressure gauge 14, so that the pressure at the outlet of the nitrogen cylinder is the maximum pressure of the cylinder; open the boosting device 12, set the boosting pressure to the test pressure P4, start boosting, until the indication of the third pressure gauge 10 reaches the test pressure P4, close the third control valve 11, the boosting device 12 and the second control valve 13 in turn.

[0079] S9, according to the type of metal material, determine the radiation line, diffraction crystal plane {hkl} and other parameters of the X-ray diffractometer 1, and determine the wavelength of the incident X-ray to be λ. Use the X-ray diffractometer 1 to emit X-rays to the test surface and receive diffraction signals, perform X-ray diffraction analysis on the test point M, and then obtain the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determine the corresponding diffraction angle 2θ0; according to the Bragg law, calculate the lattice spacing d0 of the metal material before hydrogen filling, d0=λ / 2sinθ0.

[0080] S10, open the fourth control valve 8 to discharge nitrogen, and after the indication of the third pressure gauge 10 returns to the atmospheric pressure P3, close the fourth control valve 8.

[0081] S11, open the first control valve 15 and the third control valve 11, adjust the first control valve 15 according to the indication of the first pressure gauge 16 so that the pressure at the outlet of the hydrogen cylinder is the purge pressure P2, until the indication of the third pressure gauge 10 reaches the purge pressure P2, close the third control valve 11, open the fourth control valve 8, and discharge the hydrogen; after the indication of the third pressure gauge 10 returns to the atmospheric pressure P3, close the fourth control valve 8.

[0082] S12, repeat step S11 several times until the purity of hydrogen in the high-pressure container 2 reaches 99.999%.

[0083] S13, close the fourth control valve 8, open the first control valve 15 and the third control valve 11, adjust the first control valve 15 according to the indication of the first pressure gauge 16, so that the pressure at the outlet of the hydrogen cylinder is the maximum pressure of the cylinder; open the boosting device 12, set the boosting pressure to the test pressure P4, start boosting, until the indication of the third pressure gauge 10 reaches the test pressure P4, and close the third control valve 11, the boosting device 12 and the first control valve 15 in turn.

[0084] S14, maintaining the hydrogen pressure in the high pressure container 2 at the test pressure P4 until time t is reached, and then performing XRD testing.

[0085] The time t is the time required for hydrogen to penetrate into the test surface of the test sample 3.

[0086] The time t is determined based on the current temperature, the size of the test sample and the test pressure P4, which is determined by combining the test and the finite element simulation. In the test, the time required to reach saturation is obtained by testing the hydrogen concentration of the sample after different hydrogen filling times; in the finite element simulation, the required time is evaluated based on Fick's law and the hydrogen diffusion coefficient of the material.

[0087] S15, using the X-ray diffractometer 1 to emit X-rays to the test surface and receive diffraction signals, perform X-ray diffraction analysis, obtain the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determine the corresponding diffraction angle 2θ0'; according to the Bragg law, calculate the lattice spacing d0' of the metal material after high-temperature gas phase hydrogenation, d0'=λ / 2sinθ0'.

[0088] S16, the ratio of the change in the lattice spacing of the metal material before and after hydrogen charging to the lattice spacing before hydrogen charging is used to characterize the degree of hydrogen-induced lattice distortion. From this, the degree of hydrogen-induced lattice distortion of the metal material under the high-pressure gas-phase hydrogen charging condition of the test pressure P4 can be calculated to be ε0=(d0'-d0) / d0.

[0089] Example 4

[0090] This embodiment uses the above-mentioned in-situ testing method to test the hydrogen embrittlement degree of the metal material under a set hydrogen pressure (100 MPa), including the following steps:

[0091] (1) The CrMo steel forging was processed into a test block 3 with a size of 10 mm × 10 mm × 20 mm. The test surface of the test block 3 was ground with 400 mesh, 800 mesh and 2000 mesh sandpaper respectively, and then the test surface was mechanically polished with diamond polishing paste. In order to eliminate the surface residual stress, it was polished on a vibration polishing machine for 2 h. A test point M was selected on the test surface, and the test direction of the test point M was marked with a marker.

[0092] (2) Cleaning the test device, including: cleaning the sealing ring 17 and blowing the surface of the sealing ring 17 with dry gas to ensure that the sealing ring 17 is clean; cleaning the inner surface of the high-pressure container 2 (i.e., the surface of the non-enclosed cavity) and the contact surface between the test sample 3 and the flange cover 4, and blowing them with dry gas to ensure cleanliness.

[0093] (3) Place the sealing ring 17 in the sealing groove of the high-pressure vessel 2, and place the test sample 3 in the non-enclosed cavity of the high-pressure vessel 2. Place the flange cover 4 on the test sample 3, and locate the horizontal position of the flange cover 4 through the bolt holes of the flange cover 4 and the high-pressure vessel 2. Install and tighten the bolts 5 in sequence along the diagonal line.

[0094] (4) Close the first control valve 15 and the second control valve 13, open the third control valve 11 and the fourth control valve 8, and turn on the vacuum pump 9 to start vacuuming until the reading of the third pressure gauge 10 reaches -0.1 MPa (vacuum pressure P1), then close the fourth control valve 8 and the vacuum pump 9 in turn.

[0095] (5) Open the second control valve 13 and adjust the pressure at the outlet of the nitrogen cylinder to 0.5 MPa (purge pressure P2) until the reading on the third pressure gauge 10 reaches 0.5 MPa. Then, close the third control valve 11 and open the fourth control valve 8 to discharge the nitrogen. After the reading on the third pressure gauge 10 returns to 0.1 MPa (atmospheric pressure P3), close the fourth control valve 8.

[0096] (6) Repeat step (5) five times until the purity of nitrogen in the high-pressure container 2 reaches 99.999%.

[0097] (7) Turn on the X-ray diffractometer 1 and adjust the measuring direction of the X-ray diffractometer 1 to overlap with the measuring direction marked on the test sample.

[0098] (8) Close the fourth control valve 8, open the second control valve 13 and the third control valve 11, and adjust the pressure at the outlet of the nitrogen cylinder to the maximum pressure of the cylinder; open the booster 12, set the boost pressure to 100 MPa (test pressure P4), and start boosting until the reading of the third pressure gauge 10 reaches 100 MPa, and then close the third control valve 11, the booster 12 and the second control valve 13 in turn.

[0099] (9) X-ray diffractometer 1 is used to perform XRD analysis on the marked point M of the test block 3. The incident X-rays are Cr target K α The X-ray with a wavelength of λ of 0.229093nm and a diffraction crystal plane of {211} was used to obtain the X-ray diffraction peak of the {211} crystal plane of CrMo steel, and the corresponding diffraction angle 2θ0 was determined to be 156.348°. According to the Bragg law, the lattice spacing d0 of the metal material before hydrogen charging was calculated to be 0.117030533nm.

[0100] (10) Open the fourth control valve 8 to discharge nitrogen. After the reading on the third pressure gauge 10 returns to 0.1 MPa (atmospheric pressure P3), close the fourth control valve 8.

[0101] (11) Open the first control valve 15 and the third control valve 11, and adjust the pressure at the outlet of the hydrogen cylinder to 0.5 MPa (purge pressure P2). After the reading on the third pressure gauge 10 reaches 0.5 MPa, close the third control valve 11, open the fourth control valve 8, and discharge the hydrogen. After the reading on the third pressure gauge 10 returns to 0.1 MPa (atmospheric pressure P3), close the fourth control valve 8.

[0102] (12) Repeat step (11) five times until the purity of hydrogen in the high-pressure container 2 reaches 99.999%.

[0103] (13) Close the fourth control valve 8, open the first control valve 15 and the third control valve 11, and adjust the pressure at the outlet of the hydrogen cylinder to the maximum pressure of the cylinder; open the booster 12, set the boost pressure to 100 MPa (test pressure P4), and start boosting until the reading of the third pressure gauge 10 reaches 100 MPa, and then close the third control valve 11, the booster 12 and the first control valve 15 in turn.

[0104] (14) The hydrogen pressure in the high-pressure container 2 was maintained at 100 MPa until 308 hours, and then an XRD test was performed.

[0105] Therein, based on the current temperature T of 25°C, the test sample size and the test pressure of 100 MPa, it is estimated that the time t required for hydrogen to penetrate into the test surface of the test sample is about 308 hours.

[0106] (15) The X-ray diffractometer 1 is used to perform XRD analysis on the test point M after hydrogenation, and the corresponding diffraction angle 2θ0' is obtained to be 156.603°. According to the Bragg law, the lattice spacing d0' of the metal material after high-pressure gas phase hydrogenation is calculated to be 0.116976318 nm.

[0107] (16) It is calculated that under the high-pressure gas-phase hydrogen charging condition of 100 MPa, the degree of hydrogen-induced lattice distortion ε0 of the metal material is -0.000463251.

[0108] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-pressure gas-phase hydrogen-induced lattice distortion in-situ testing method, characterized in that: An in-situ testing device is used, the device comprising: an X-ray diffractometer (1), a high-pressure container (2); The high-pressure container (2) is a non-enclosed cavity structure, used for placing a test sample (3); the test sample (3) is placed in the non-enclosed cavity of the high-pressure container (2), and forms a seal for the non-enclosed cavity; The air inlet of the high-pressure container (2) is connected to an air inlet pipeline (7) for inputting gas into the non-enclosed cavity of the high-pressure container (2); A side of the test sample (3) away from the non-enclosed cavity serves as a test surface; the X-ray diffractometer (1) is used to emit X-rays to the test surface and receive diffraction signals; The in-situ testing method includes the following steps: Step 1, processing the metal material into a test specimen (3); Step 2: placing the test sample (3) in the non-enclosed cavity of the high-pressure container (2) to form a seal for the non-enclosed cavity; Step 3, inputting a high-pressure inert gas of a set pressure, i.e., a test pressure P4, into the non-enclosed cavity of the high-pressure container (2), emitting X-rays to the test surface of the test sample (3) using an X-ray diffractometer (1) and receiving diffraction signals, performing X-ray diffraction analysis, and obtaining a corresponding diffraction angle of 2θ0, thereby calculating the lattice spacing d0 of the test sample (3) before hydrogen filling, d0=λ / 2sinθ0, where λ is the wavelength of the X-rays; Step 4: High-pressure hydrogen gas of a set pressure, i.e., a test pressure P4, is input into the non-enclosed cavity of the high-pressure container (2); an X-ray diffractometer (1) is used to emit X-rays to the test surface of the test sample (3) and receive diffraction signals, and an X-ray diffraction analysis is performed to obtain a corresponding diffraction angle of 2θ0', thereby calculating the lattice spacing d0' of the test sample (3) after hydrogen filling, d0'=λ / 2sinθ0'; Step 5, calculating the degree of hydrogen-induced lattice distortion ε0=(d0'-d0) / d0 of the metal material under the high-pressure gas-phase hydrogen charging condition.

2. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 1, characterized in that: The gas outlet of the high-pressure container (2) is connected to a gas outlet pipeline (6) for discharging gas in the non-enclosed cavity of the high-pressure container (2); The air intake pipeline (7) is provided with a pressurizing device (12), a third control valve (11) and a third pressure gauge (10) in sequence along the gas transmission direction; the pressurizing device (12) is used to pressurize the gas; A fourth control valve (8) and a vacuum pump (9) are sequentially arranged on the gas outlet pipeline (6) along the gas transmission direction; the vacuum pump (9) is used to extract the gas.

3. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 2, characterized in that: The air inlet of the high-pressure container (2) is connected to a nitrogen bottle and a hydrogen bottle respectively through an air inlet pipeline (7) for inputting nitrogen / hydrogen into the non-enclosed cavity of the high-pressure container (2); a second control valve (13) and a second pressure gauge (14) are provided at the outlet of the nitrogen bottle; and a first control valve (15) and a first pressure gauge (16) are provided at the outlet of the hydrogen bottle.

4. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 1, characterized in that: The test specimen (3) is in the shape of a boss, comprising a raised portion and a platform portion; the raised portion is placed in a non-enclosed cavity, and the shape of the non-enclosed cavity matches that of the raised portion; the platform portion is located above the high-pressure container (2) to achieve sealing of the non-enclosed cavity.

5. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 4, characterized in that: A sealing groove is provided on the upper surface of the high-pressure container (2); a sealing ring (17) is placed in the sealing groove and is used to contact the test sample (3) to prevent gas in the non-enclosed cavity from escaping.

6. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 4, characterized in that: After the test sample (3) is placed in the non-enclosed cavity, a flange cover (4) is placed on the test sample (3), and the flange cover (4) is connected to the high-pressure container (2) via bolts (5) to compress the test sample (3).

7. The in-situ testing method for high pressure gas phase hydrogen induced lattice distortion according to claim 3, characterized in that: The specific process of the method is as follows: S1, processing a metal material into a test specimen (3), grinding and polishing a test surface of the test specimen (3), selecting a test point on the test surface, and marking a test direction of the test point; S2, cleaning the test device; S3, placing the test sample (3) in the non-enclosed cavity of the high-pressure container (2) to seal the non-enclosed cavity; S4, closing the second control valve (13) and the first control valve (15), opening the third control valve (11) and the fourth control valve (8), and turning on the vacuum pump (9) to start vacuuming until the reading on the third pressure gauge (10) reaches the vacuum pressure P1, and then closing the fourth control valve (8) and the vacuum pump (9) in sequence; S5, opening the second control valve (13) and adjusting the pressure at the outlet of the nitrogen bottle to the purge pressure P2, until the reading on the third pressure gauge (10) reaches the purge pressure P2, closing the third control valve (11), opening the fourth control valve (8) to discharge the nitrogen; after the reading on the third pressure gauge (10) returns to the atmospheric pressure P3, closing the fourth control valve (8); S6, repeat step S5 several times; S7, turning on the X-ray diffractometer (1), and adjusting the measurement direction of the X-ray diffractometer (1) to be consistent with the measurement direction of the test point; S8, close the fourth control valve (8), open the second control valve (13) and the third control valve (11), Open the pressure boosting device (12) to start pressure boosting until the reading on the third pressure gauge (10) reaches a set pressure, i.e., the test pressure P4, and then close the third control valve (11), the pressure boosting device (12), and the second control valve (13) in sequence; S9, determining the radiation line and diffraction crystal plane {hkl} of the X-ray diffractometer (1) according to the type of the metal material, and determining the incident X-ray wavelength λ, using the X-ray diffractometer (1) to emit X-rays to the test surface and receive diffraction signals, performing X-ray diffraction analysis, obtaining the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determining the corresponding diffraction angle 2θ0; according to the Bragg law, calculating the lattice spacing d0 of the metal material before hydrogen filling, d0=λ / 2sinθ0; S10, opening the fourth control valve (8) to discharge nitrogen, and after the reading of the third pressure gauge (10) returns to the atmospheric pressure P3, closing the fourth control valve (8); S11, opening the first control valve (15) and the third control valve (11), adjusting the pressure at the outlet of the hydrogen cylinder to the purge pressure P2, until the reading on the third pressure gauge (10) reaches the purge pressure P2, closing the third control valve (11), opening the fourth control valve (8), and discharging the hydrogen; after the reading on the third pressure gauge (10) returns to the atmospheric pressure P3, closing the fourth control valve (8); S12, repeat step S11 several times; S13, closing the fourth control valve (8), opening the second control valve (13) and the first control valve (15), and opening the pressure boosting device (12) to start pressure boosting until the reading of the third pressure gauge (10) reaches a set pressure, i.e., a test pressure P4, and then closing the third control valve (11), the pressure boosting device (12), and the first control valve (15) in sequence; S14, maintaining the hydrogen pressure in the high pressure container (2) at the test pressure P4 until time t is reached; The time t is the time required for hydrogen to penetrate the test surface of the test sample (3); S15, using an X-ray diffractometer (1) to emit X-rays to the test surface and receive diffraction signals, perform X-ray diffraction analysis, obtain the X-ray diffraction peak of the diffraction crystal plane {hkl} of the metal material, and determine the corresponding diffraction angle 2θ0'; according to Bragg's law, calculate the lattice spacing d0' of the metal material after hydrogen filling, d0'=λ / 2sinθ0'; S16, calculate the degree of hydrogen-induced lattice distortion of the metal material under the high-pressure gas phase hydrogen charging condition of the test pressure P4, ε0 = (d0'-d0) / d 0。

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