CN117110053B - Method for testing hydrogen embrittlement sensitivity of aluminum alloy material in simulated high-pressure hydrogen environment - Google Patents
Method for testing hydrogen embrittlement sensitivity of aluminum alloy material in simulated high-pressure hydrogen environment Download PDFInfo
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- 238000009864 tensile test Methods 0.000 description 51
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- 229910000853 7075 T6 aluminium alloy Inorganic materials 0.000 description 17
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- 229910000755 6061-T6 aluminium alloy Inorganic materials 0.000 description 11
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229920000049 Carbon (fiber) Polymers 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
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Abstract
The invention relates to a method for testing hydrogen embrittlement sensitivity of an aluminum alloy material in a simulated high-pressure hydrogen environment. The method comprises the following steps: at a temperature T of 20-35 ℃ and a first humidity phi 1 of 0-10%RH, the temperature is 10% ‑7 ~10 ‑6 The method comprises the steps of (1) performing a first slow strain rate stretching experiment on an aluminum alloy material at a mm/s strain rate v to obtain a first elongation after break A1; performing a second slow strain rate stretching experiment at a strain rate v under the conditions of a temperature T and a second humidity phi 2 of 40% -60% RH to obtain a second post-breaking elongation A2 and a simulated hydrogen pressure P in a simulated high-pressure hydrogen environment H2 70-105 MPa; calculating the hydrogen embrittlement sensitivity index I of the aluminum alloy material in a simulated high-pressure hydrogen environment according to the formula I= (A1-A2)/A1 multiplied by 100%; comparing I with 10% of a reference value, and determining the hydrogen embrittlement sensitivity of the aluminum alloy material in a simulated high-pressure hydrogen environment.
Description
Technical Field
The invention relates to the technical field of material performance testing, in particular to a method for testing hydrogen embrittlement sensitivity of an aluminum alloy material in a simulated high-pressure hydrogen environment.
Background
Hydrogen energy is known as the ultimate energy source of the 21 st century and is a great strategic direction for the global energy technical revolution and transformation development. The safe and efficient hydrogen storage technology is a key link of a hydrogen energy industry chain. The most mature and widely used aluminum alloy hydrogen storage tank at present has an aluminum alloy inner container and a carbon fiber material coating the periphery of the inner container. The hydrogen storage density of a conventional 35MPa hydrogen storage tank is only 2.4 and wt percent, the hydrogen storage density of a next-generation hydrogen fuel vehicle needs to be improved to be more than 6.5 and wt percent, and the corresponding hydrogen storage pressure needs to be more than 70 MPa. The liner material of the hydrogen storage tank is used in a high-pressure and high-purity hydrogen environment for a long time, so that the local plasticity is easy to be reduced, the crack is rapidly expanded, the durability is reduced, the high-pressure hydrogen embrittlement is generated, the fracture failure of the hydrogen storage tank is further caused, and the safety accident is generated. Therefore, in order to ensure long-term, stable and reliable operation, special attention needs to be paid to the hydrogen embrittlement sensitivity of the aluminum alloy material under high-pressure hydrogen environment.
However, in the prior art, two types of conventional hydrogen embrittlement sensitivity test devices are mainly used, one type is to directly build a high-pressure hydrogen kettle, and the other type is to utilize electrochemical reaction to permeate hydrogen. For example, patent application CN 113466427a provides a system for testing hydrogen embrittlement resistance and life of a material in a high-pressure hydrogen environment, which comprises a slow strain rate tensile testing machine, a high-pressure gas kettle, a constant temperature circulator, an oxygen concentration detector, a burner and other devices, and can perform a slow strain rate tensile and low cycle load fatigue test of the material in a multi-component high-pressure gas environment. The patent application CN115032063A provides a device and a method for testing the hydrogen embrittlement sensitivity of a material for simulating the stress state of a gas cylinder by adding an electrolytic charging solution into a medium tank, carrying out electrochemical charging by taking a sample as a cathode and simultaneously applying and maintaining the stress level not lower than the service condition of the gas cylinder. Patent CN112461659B, by means of electrolytic hydrogen permeation, hydrogen permeation is carried out on a 6061-T6 aluminum alloy sample, and then the tensile strength and yield strength of a sample hydrogen permeation layer after electrolytic hydrogen permeation are calculated by adopting an equal strain model, so that the hydrogen induced damage degree of the 6061-T6 aluminum alloy is evaluated.
In the existing test method, the high-pressure hydrogen kettle is relatively close to the real service condition of the hydrogen storage tank, but can rarely realize the loading of hydrogen pressure above 70MPa, expensive high-pressure resistant equipment is required to be customized, a special explosion-proof laboratory is established, and the cost investment is large; in addition, hydrogen is an explosive hazard source, so that the test hazard is high, and the hydrogen is difficult to popularize in a laboratory. The electrolytic hydrogen permeation device is simple and convenient and is simple to operate, but the electrochemical process parameter change can only simulate the hydrogen concentration in the material, so that the diffusion rate and the distribution state of hydrogen atoms under the working condition of ultrahigh hydrogen pressure above 70MPa are difficult to simulate, and the difference exists between the diffusion rate and the distribution state and the actual service state of the hydrogen storage tank.
Therefore, a method for testing the hydrogen embrittlement sensitivity of the aluminum alloy material in a simulated high-pressure hydrogen environment is needed, and the problem that the high-hydrogen pressure testing environment of the aluminum alloy material with the pressure of more than 70MPa is difficult to simulate in the prior art is solved.
Disclosure of Invention
The invention aims to provide a method for testing hydrogen embrittlement sensitivity of an aluminum alloy material in a simulated high-pressure hydrogen environment, so as to solve the technical problem that the high-pressure hydrogen testing environment of the aluminum alloy material is difficult to simulate with the pressure of more than 70MPa in the prior art.
In order to achieve the above object, the present invention provides a method for testing hydrogen embrittlement sensitivity of an aluminum alloy material in a simulated high pressure hydrogen environment, the method comprising:
s1: at the temperature T and the first humidity phi 1, the aluminum alloy material is slowly processed for the first time at the strain rate vThe strain rate stretching experiment is carried out to obtain the first elongation after break A1, the temperature T is 20-35 ℃, the first humidity phi 1 is 0-10% RH, and the strain rate v is 10 -7 ~10 -6 mm/s；
S2: under the conditions of temperature T and second humidity phi 2, carrying out a second slow strain rate stretching experiment on the aluminum alloy material at a strain rate v to obtain a second after-break elongation A2 under the simulated high-pressure hydrogen environment, wherein the second humidity phi 2 is 40% -60% RH, and the simulated hydrogen pressure P of the simulated high-pressure hydrogen environment is obtained H2 70-105 MPa;
s3: according to the following formula 1, the hydrogen embrittlement sensitivity index I of the aluminum alloy material under the simulated high-pressure hydrogen environment is calculated,
equation 1: i= (A1-A2)/a1×100%;
s4: comparing the hydrogen embrittlement sensitivity index I with a reference value of 10%, if the hydrogen embrittlement sensitivity index I is more than or equal to 10%, determining that the aluminum alloy material is hydrogen embrittlement sensitive in a simulated high-pressure hydrogen environment, and if the hydrogen embrittlement sensitivity index I is less than 10%, determining that the aluminum alloy material is hydrogen embrittlement insensitive in the simulated high-pressure hydrogen environment.
Preferably, the temperature T is 25 ℃.
Preferably, the first humidity φ 1 is 5% RH.
Preferably, the second humidity φ 2 is 40% RH.
Preferably, the second humidity φ 2 is 50% RH.
Preferably, the second humidity φ 2 is 60% RH.
Preferably, the temperature T is 25 ℃, the second humidity phi 2 is 40% RH, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 70 MPa.
Preferably, the temperature T is 25 ℃, the second humidity phi 2 is 50% RH, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 87.5 MPa.
Preferably, the temperature T is 25 ℃, the second humidity phi 2 is 60% RH, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 105 MPa.
Preferably, prior to step S1, the method of the invention further comprises the steps of: polishing and ultrasonic cleaning are carried out on the aluminum alloy material.
Aiming at the technical problem that the high hydrogen pressure test environment of the aluminum alloy material with the pressure of more than 70MPa is difficult to simulate in the prior art, the invention provides a method for stretching the aluminum alloy material with a slow strain rate in wet air with a certain humidity range, and simulating an actual high hydrogen pressure working condition by high-pressure hydrogen generated by hydrolysis reaction on the fresh surface of the aluminum alloy material, so that the hydrogen embrittlement sensitivity of the aluminum alloy material in the high hydrogen pressure environment with the pressure of more than 70MPa can be conveniently tested.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention. In the drawings:
FIG. 1 shows a schematic diagram of an experimental system employed by a test method according to one embodiment of the invention.
Fig. 2 shows alloy stress strain graphs for 7075-T6 aluminum alloys in a simulated hydrogen pressure test environment according to example 1 (left panel) and in an actual 70MPa hydrogen pressure environment (right panel).
Detailed Description
It should be noted that, in the case of no conflict, the embodiments and features in the embodiments may be combined with each other. The present invention will be described in detail with reference to examples.
In order to solve the technical problem that the high hydrogen pressure test environment of the aluminum alloy material with the pressure of more than 70MPa is difficult to simulate, the invention provides a method for testing the hydrogen embrittlement sensitivity of the aluminum alloy material in the high-pressure hydrogen simulation environment, which comprises the following steps:
s1: carrying out a first slow strain rate stretching experiment on the aluminum alloy material at a strain rate v under the temperature T and the first humidity phi 1 to obtain a first elongation after break A1, wherein the temperature T is 20-35 ℃, the first humidity phi 1 is 0-10% RH, and the strain rate v is 10 -7 ~10 -6 mm/s；
S2: performing a second slow strain rate stretching experiment on the aluminum alloy material at a strain rate v under the conditions of the temperature T and the second humidity phi 2 to obtain a second after-break elongation A2 under the simulated high-pressure hydrogen environment, wherein the second humidity phi 2 is 40% -60% RH, and the simulation is performedSimulated hydrogen pressure P of high-pressure hydrogen environment H2 70-105 MPa;
s3: according to the following formula 1, the hydrogen embrittlement sensitivity index I of the aluminum alloy material under the simulated high-pressure hydrogen environment is calculated,
equation 1: i= (A1-A2)/a1×100%;
s4: comparing the hydrogen embrittlement sensitivity index I with a reference value of 10%, if the hydrogen embrittlement sensitivity index I is more than or equal to 10%, determining that the aluminum alloy material is hydrogen embrittlement sensitive in a simulated high-pressure hydrogen environment, and if the hydrogen embrittlement sensitivity index I is less than 10%, determining that the aluminum alloy material is hydrogen embrittlement insensitive in the simulated high-pressure hydrogen environment.
The method simulates the actual high-hydrogen pressure working condition by high-pressure hydrogen generated by hydrolysis reaction on the fresh surface when the aluminum alloy material stretches at a slow strain rate in wet air.
According to the invention, when the aluminum alloy is stretched in wet air at a low strain rate, the oxide layer on the surface of the aluminum alloy is gradually broken due to plastic deformation, the leaked fresh surface activity is very high, the aluminum alloy is extremely easy to react with surrounding water vapor, high-pressure hydrogen is generated, and the hydrogen partial pressure can be increased along with the increase of the ambient humidity. According to the Gibbs free energy of the hydrolysis reaction of the aluminum alloy and the steam wet enthalpy diagram, a quantitative relation model between the ambient temperature, the humidity and the hydrogen partial pressure generated by the hydrolysis reaction can be established, and further, the hydrogen embrittlement sensitivity index of the material under the corresponding hydrogen pressure can be obtained by comparing the change of the elongation of the material after the slow strain rate stretching process is interrupted under the conditions of a dry atmosphere and a certain humidity.
The invention establishes the simulated hydrogen pressure (P) based on the theoretical basis and a large number of experiments H2 ) Empirical model of the calculation relationship with the test humidity (phi) and temperature (T), namely: p (P) H2 =k.phi.exp (25.5-5202.6/T) ×exp (35923.4/T). Wherein K is an empirical constant of 2.628 x 10 -48 The method comprises the steps of carrying out a first treatment on the surface of the Wherein T is given in Kelvin (K). In practical application, the unit of the value of T can be converted from K to the temperature. The empirical model lays a foundation for selecting proper humidity and temperature conditions for target simulated hydrogen pressure.
Based on the empirical model, the invention discovers that the high hydrogen pressure environment of 70-105 MPa can be simulated for the aluminum alloy material in the slow strain rate stretching experiment by setting the humidity to 40% -60% RH in the environment (20 ℃ -35 ℃) close to the room temperature. The difficulty of the simulation test of the high-hydrogen pressure environment is greatly reduced.
In order to verify the reliability of the simulated high-hydrogen pressure environment obtained by the empirical model, an aluminum alloy material is placed under the conditions of set temperature and humidity (20-35 ℃ and 40-60% RH) to carry out a slow strain rate stretching experiment, the obtained alloy stress strain curve is compared with the stress strain curve of the same alloy material in the actual high-hydrogen pressure environment, and the coincidence of the alloy stress strain curve in the simulated high-hydrogen pressure environment and the alloy stress strain curve of the aluminum alloy material in the actual high-hydrogen pressure environment of 70-105 MPa is confirmed.
For example, FIG. 2 shows alloy stress strain graphs for 7075-T6 aluminum alloys in a 70MPa simulated hydrogen pressure test environment (left panel) and in an actual 70MPa hydrogen pressure environment (right panel). Wherein the left graph in FIG. 2 shows that the 7075-T6 aluminum alloy has a temperature of 25 ℃, a humidity phi 2 of 40% RH, and a tensile strain rate v of 10 -6 Stress-strain curves obtained by repeating the experiment for three times under the test condition of mm/s (corresponding to the simulated hydrogen pressure of 70 MPa); while the right graph in fig. 2 shows the stress-strain curve obtained by three repeated experiments of the 7075-T6 aluminum alloy in an actual 70MPa hydrogen pressure environment. By comparison, the left and right graphs can be found to have higher anastomosis degree, and the reliability of the simulated high-hydrogen pressure environment can be proved.
Further, the hydrogen embrittlement sensitivity of the aluminum alloy material can be effectively evaluated by comparing the change of the elongation after breaking of the aluminum alloy material in the two different environments of the dry atmosphere and the wet air. Specifically, the method provided by the invention is used for respectively testing the elongation after the aluminum alloy material is stretched and broken at slow strain rates under the conditions of the same temperature T and different humidity, wherein the humidity phi 1 is a dry environment, the humidity value is 0% -10% RH, and the measured elongation after breaking is A1; humidity phi 2 is a water vapor environment, humidity value is 40% -60% RH, and the measured elongation after break is A2. According to the followingEquation 1 calculates the corresponding hydrogen pressure P of the material under the working condition (T, phi 2) H2 Lower hydrogen embrittlement sensitivity index I.
Equation 1
Proved by experiments, the method can be used for measuring the simulated hydrogen pressure P H2 The hydrogen embrittlement sensitivity index of the aluminum alloy material in a high-hydrogen pressure environment of 70-105 MPa. By comparing the measured hydrogen embrittlement sensitivity index with a reference value of 10%, it can be determined whether the aluminum alloy material is hydrogen embrittlement-sensitive in the high hydrogen pressure environment. If the hydrogen embrittlement sensitivity index I is more than or equal to 10%, determining the hydrogen embrittlement sensitivity of the aluminum alloy material in the simulated high-pressure hydrogen environment; if the hydrogen embrittlement sensitivity index I is less than 10%, the aluminum alloy material is not sensitive to hydrogen embrittlement under the simulated high-pressure hydrogen environment.
The method creatively proposes that the aluminum alloy material is subjected to slow strain rate stretching treatment by adjusting and controlling temperature and humidity conditions in a laboratory environment, so that a high-hydrogen pressure environment of 70-105 MPa can be conveniently and safely simulated, and the effective measurement of hydrogen embrittlement sensitivity of the aluminum alloy material in the high-pressure hydrogen environment is realized. The invention ingeniously utilizes the following findings: the aluminum alloy material is exposed to fresh surfaces and undergoes hydrolysis reactions by slow strain rate stretching in a specific humidity environment, whereby high pressure hydrogen gas can be generated. According to the gibbs free energy and the steam wet enthalpy diagram of the aluminum alloy hydrolysis reaction, a calculation relation experience model between temperature, humidity and corresponding pressure is obtained through a large number of experimental verification, and based on the experience model, temperature and humidity conditions which are safer and more suitable for laboratory operation are selected, so that the determination of the hydrogen embrittlement sensitivity of the aluminum alloy material under the simulated high-hydrogen pressure environment of 70-105 MPa is realized.
In the method of the invention, the temperature is controlled to be 20-35 ℃, preferably 25-30 ℃, and the first humidity and the second humidity are respectively controlled to be in the range of 0% -10% RH and 40% -60% RH. These temperature and humidity ranges are readily achievable by conventional materials laboratories and meet the temperature and humidity requirement standards of materials laboratories. Therefore, the invention has the remarkable advantages that the experimental risk of simulating the high-hydrogen pressure environment can be greatly reduced, and the convenience of laboratory operation is greatly improved.
More specifically, selecting the second humidity in the range of 40% -60% rh has the following significant advantages:
convenience: the humidity is kept in the range of 40% -60% RH, and the humidity is not greatly different from the indoor humidity, so that the instrument is more accurate in humidity regulation and control;
security: compared with the corrosiveness of high humidity, the low humidity is kept, so that the safety of operators and the stable operation of instruments are facilitated;
-materialization: when the humidity is too high, moisture is easily condensed at the crack of the sample, which is unfavorable for the continuous progress of the reaction.
In the process of the present invention, it is necessary to specifically control the slow strain elongation rate to not more than 10 -6 mm/s, preferably at 10 -7 ~10 -6 In the range of mm/s. If the rate is higher than 10 -6 mm/s, no brittle crack initiation and propagation can be found by observing the fracture structure of the aluminum alloy material, which means that the fracture structure is higher than 10 -6 No hydrogen embrittlement breaks occur at the tensile rate of mm/s. If the rate is too low, e.g. below 10 -7 mm/s, although hydrogen embrittlement fracture can be observed, the experiment duration is too long, which is unfavorable for the convenient development of the experiment. Therefore, the invention preferably selects the slow strain stretching rate to be 10 -7 ~10 -6 In the range of mm/s, the hydrogen embrittlement fracture of the aluminum alloy material can be realized with a relatively short experimental period, and further the hydrogen embrittlement sensitivity test of the aluminum alloy material can be realized.
In the method of the present invention, in order to improve the convenience of operation, it is preferable that the test temperature T is set to normal temperature 25 ℃.
In the method of the present invention, in order to improve the convenience of operation, it is preferable that the first humidity Φ1 is set to 5% rh.
In the method of the present invention, in order to improve the convenience of operation, it is preferable that the second humidity Φ2 is set to 40% rh.
In the method of the present invention, in order to improve the convenience of operation, it is preferable that the second humidity Φ2 is set to 50% rh.
In the method of the present invention, in order to improve the convenience of operation, it is preferable that the second humidity Φ2 is set to 60% rh.
In a specific embodiment, the temperature T is set to 25℃and the second humidity φ 2 is set to 40% RH, corresponding to the simulated hydrogen pressure P simulating a high-pressure hydrogen environment H2 70 MPa.
In a specific embodiment, the temperature T is set to 25 ℃, the second humidity phi 2 is set to 50% RH, and the simulated hydrogen pressure P corresponding to the simulated high pressure hydrogen environment H2 87.5 MPa.
In another specific embodiment, the temperature T is set to 25 ℃, the second humidity phi 2 is set to 60% RH, and the simulated hydrogen pressure P corresponding to the simulated high pressure hydrogen environment H2 105 MPa.
Preferably, before step S1, the method of the invention further comprises the steps of: polishing and ultrasonic cleaning are carried out on the aluminum alloy material. The polishing and ultrasonic cleaning are beneficial to removing the surface foreign matters of the aluminum alloy material on one hand, and can reduce the local defects of the material on the other hand. Therefore, the method can facilitate the exposure of the fresh surface of the aluminum alloy, is favorable for the occurrence of hydrolysis oxidation reaction, and ensures that the elongation rate test is more accurate and reliable. The extent of sanding and ultrasonic cleaning is preferably such that the surface roughness of the aluminum alloy material is < 0.4 μm, more preferably < 0.35 μm, most preferably < 0.32 μm.
In order to implement the above test method of the present invention, an experimental system capable of controlling temperature and humidity conditions while performing a slow strain rate stretching experiment may be selected.
For example, the following experimental system for testing the hydrogen embrittlement sensitivity of aluminum alloy materials in a simulated high pressure hydrogen environment can be employed, which mainly comprises a slow strain rate tensile tester and a matched clamp and tensile sample for testing the elongation after fracture at a low strain rate, a high-low temperature alternating humidity and heat test box for providing a specific temperature and humidity environment, and an air compressor and a matched intercooler for manufacturing compressed air. More specifically, the experimental system may include:
the slow strain rate tensile testing machine mainly comprises a control cabinet and a host unit;
a clamp matched with the slow strain rate tensile testing machine;
the high-low temperature alternating damp-heat test box is matched with the slow strain rate tensile testing machine; the main function of the high-low temperature alternating damp-heat test box is to provide a temperature and humidity change environment, and an air dryer, a heater, a refrigeration evaporator and a blower fan are contained in the test box to ensure the temperature and humidity requirements of a working chamber; the high-low temperature alternating damp-heat test box body is provided with a lifting cylinder and universal casters, can be pushed between two vertical columns of the main machine of the slow strain tensile testing machine, and enables a top sealing strip of the box body to be in contact seal with a panel of the slow strain tensile testing machine through the lifting cylinder;
an air compressor for producing compressed air for the high-low temperature alternating damp-heat test chamber;
an intercooler for providing a subsequent cooling process for the air compressor.
Preferably, the slow strain rate tensile testing machine and the high-low temperature alternating damp-heat testing box are placed in a laboratory;
preferably, the temperature range of the high-low temperature alternating damp-heat test box is 20-100 ℃, the normal temperature is preferably normal temperature-100 ℃, the humidity range is 0-98% RH, the humidity range is preferably 5-98% RH, the temperature fluctuation degree is less than or equal to +/-0.5 ℃, and the temperature uniformity is +/-2 ℃;
preferably, the air compressor and intercooler are placed outside the laboratory at dry ventilation.
For example, reference may be made to FIG. 1, which shows a schematic diagram of an experimental system employed by the test method according to one embodiment of the invention. The experiment system comprises a main unit 1 of a slow strain rate tensile testing machine, a high-low temperature alternating wet heat testing box 2, a control cabinet 3, an air compressor 4 and an intercooler 5. Although fig. 1 does not specifically show the connection relationship between the devices, those skilled in the art can know the connection relationship between them based on the test method of the present invention. Specifically, the main unit 1 is arranged at the upper part of the high-low temperature alternating damp-heat test chamber 2, and the two are connected with each other; the control cabinet 3 is connected with the host unit 1, and the control cabinet 3 is used for controlling the condition parameters and the experiment process of the low-strain stretching experiment; the air outlet of the air compressor 4 is connected to the air inlet of the intercooler 5, and the air outlet of the intercooler 5 is connected to the high-low temperature alternating wet heat test chamber 2, and both the air compressor 4 and the intercooler 5 are used together to provide air in a suitable temperature and humidity range.
According to a specific embodiment, the method for testing the hydrogen embrittlement sensitivity of the aluminum alloy material in the simulated high-pressure hydrogen environment mainly comprises the steps of surface treatment of a tensile sample, testing of the elongation after the tensile break under slow strain in a dry environment, testing of the elongation after the tensile break under slow strain rate in a specific humidity environment, calculation and comparison of the elongation change values after the tensile break under different environments and the like.
More specifically, according to one embodiment of the present invention, the method comprises the steps of:
firstly, processing an aluminum alloy material into a dumbbell-shaped tensile sample 2 piece, and carrying out local polishing and ultrasonic cleaning on the parallel end of the sample until the surface roughness of the sample is less than 0.32 mu m;
step two, starting a slow strain rate tensile testing machine, pushing a high-low temperature alternating damp-heat test box into a space between two vertical columns of a main machine of the slow strain rate tensile testing machine;
step three, opening a front door of the test box, and installing a first tensile sample to ensure that the stress direction of the sample is consistent with the loading direction of a mechanical force value of the slow strain rate tensile test;
step four, closing a front door of the test box, enabling a sealing strip on the test box to be in contact with a panel of the slow strain rate tensile test machine through a lifting cylinder, and compressing the sealing strip to a half height so as to ensure full sealing;
step five, starting an air compressor, an intercooler and a test box in sequence, and setting the temperature T and the humidity phi 1 of the test box, wherein the temperature T is preferably 20-35 ℃, and the humidity phi 1 is a dry environment and is preferably 0-10% RH;
step six, after the temperature and humidity of the test box are stable, setting a slow strain stretching rate v of the material, starting stretching until breaking, testing the elongation A1 after breaking, wherein the slow strain stretching rate v is preferably 10 -6 mm/s or less, more preferably 10 -7 ~10 -6 mm/s；
Step seven, opening a front door of the test box, taking out the tensile sample, and observing the initiation and the expansion of brittle cracks in fracture tissues of the tensile sample, thereby judging hydrogen embrittlement fracture;
step eight, repeating the steps two to four, and installing a second tensile sample;
step nine, keeping the temperature T in the step five unchanged, and changing the humidity of the set test box to phi 2, wherein phi 2 is 40% -60% RH;
setting a slow strain stretching rate v to be the same as that in the step six after the temperature and humidity of the test box are stable, starting stretching until the test box breaks, and testing the elongation A2 after breaking; in this step, a high hydrogen pressure environment is generated due to the hydrolysis and oxidation reaction of the fresh surface of the aluminum alloy material in the wet air, and the corresponding simulated hydrogen pressure P of the high hydrogen pressure environment is confirmed through empirical model calculation and alloy stress-strain curve comparison H2 70-105 MPa;
step eleven, opening a front door of the test box, taking out a sample, and observing the initiation and the expansion of brittle cracks in fracture tissues of the sample, thereby judging hydrogen embrittlement fracture;
step twelve, according to formula 1: i= (A1-A2)/A1 multiplied by 100 percent, and calculating the simulated hydrogen pressure P of the aluminum alloy material H2 Hydrogen embrittlement sensitivity index under conditions I;
thirteenth, repeating the steps one to twelve, taking the average value of the three test results as the final aluminum alloy material in the simulated hydrogen pressure P H2 Hydrogen embrittlement sensitivity index under conditions. If it isMore than or equal to 10 percent, the material can be considered to be sensitive to hydrogen embrittlement under the pressure of the hydrogen; if I < 10%, the material is considered to be hydrogen embrittlement insensitive at the hydrogen pressure.
In the actual testing process, the aluminum alloy material can be selected to be prepared into different types such as dumbbell type, sheet type, rod type, thread type and the like according to different aluminum alloy materials and laboratory environments and other factors.
According to different test precision requirements, the test method of the invention can be repeated for a plurality of times, for example, can be repeated for two times, three times, five times, etc.
Compared with the existing simulation test method, the method provided by the invention has obvious advantages. The conventional method for building the high-pressure hydrogen kettle to test the hydrogen embrittlement sensitivity of the material needs to customize expensive high-pressure resistant equipment, builds a special explosion-proof laboratory, has large cost investment, can realize the hydrogen pressure of more than 70MPa, and has high test risk because hydrogen is an explosion-prone hazard source, and is difficult to popularize in the laboratory; the method for indirectly testing the hydrogen embrittlement sensitivity by utilizing the electrochemical reaction hydrogen charging is simple and convenient in an electrolytic hydrogen permeation device and simple in operation, but only can simulate the hydrogen concentration in a material by changing electrochemical technological parameters, and is difficult to simulate the diffusion rate and the distribution state of hydrogen atoms under the working condition of ultrahigh hydrogen pressure of more than 70MPa, and the difference exists between the diffusion rate and the distribution state and the actual service state of a hydrogen storage tank. The invention solves the problem that the service condition of the existing material in the hydrogen embrittlement sensitivity research is difficult to simulate by a gas permeation hydrogen method or a solution permeation hydrogen method. And, the present invention further has the following advantages: expensive high-pressure resistant equipment and an explosion-proof laboratory are not required to be customized, and equipment investment is small; the test is safe and reliable, the operation is simple, the test period is short, and the popularization in a laboratory is facilitated.
The advantageous effects of the present invention will be further described below with reference to examples.
Example 1
1.1 Experimental system
In example 1, the experimental system for simulating the hydrogen embrittlement sensitivity of the aluminum alloy material under the high-pressure hydrogen environment comprises:
the slow strain rate tensile testing machine mainly comprises a control cabinet and a host unit, wherein the host unit comprises a bearing frame, a loading unit, a deformation measuring device, a table panel, a pull rod, a sample clamp, a reaction frame and the like;
the clamp and the tensile sample are matched with the slow strain rate tensile testing machine, the clamp is a plate clamp with the thickness of 1mm, the tensile sample is an aluminum alloy material tensile test piece with the thickness of 1mm, and the tensile sample is connected with the two clamps through two round hole bolts;
the high-low temperature alternating damp-heat test box matched with the slow strain rate tensile testing machine has the main functions of providing a temperature and humidity change environment, and comprises an air dryer, a heater, a refrigeration evaporator and a blower fan so as to ensure the temperature and humidity requirements of a working chamber. The high-low temperature alternating damp-heat test box body is provided with a lifting cylinder and universal casters, can be pushed between two upright posts of the main machine of the slow strain rate tensile testing machine, and enables a top sealing strip of the high-low temperature alternating damp-heat test box body to be in contact seal with a table panel of the slow strain rate tensile testing machine through the lifting cylinder. The temperature range of the high-low temperature alternating damp-heat test box is normal temperature-100 ℃, the humidity range is 5-98% RH, the temperature fluctuation degree is less than or equal to +/-0.5 ℃, and the temperature uniformity is +/-2 ℃;
the air compressor is used for manufacturing compressed air for the high-low temperature alternating humidity and heat test box and is a novel rotary air compressor;
and the intercooler is used for providing subsequent gas cooling treatment for the air compressor.
The slow strain rate tensile testing machine and the high-low temperature alternating damp-heat testing box are arranged in a laboratory; the air compressor and the intercooler are arranged at the dry ventilation position outside the laboratory.
1.2 Test method
The hydrogen embrittlement sensitivity test of the aluminum alloy material in the simulated high-pressure hydrogen environment is carried out according to the following steps:
step one, processing a 7075-T6 aluminum alloy plate into a1 mm-thick tensile test piece 2, wherein the tensile test piece is 116mm in length, 24mm in length at the parallel end, and a round hole with the diameter of 10mm is respectively arranged between the clamping ends at the two ends, and the distance between the two circle centers is 84mm. Carrying out local polishing and ultrasonic cleaning on the parallel end of the sample until the surface roughness of the sample is less than 0.3 mu m;
step two, starting a slow strain rate tensile testing machine, and pushing a test box into a space between two upright posts of a main machine of the slow strain rate tensile testing machine;
step three, opening a front door of the test box, and installing a first tensile sample to ensure that the stress direction of the sample is consistent with the loading direction of a mechanical force value of the slow strain rate tensile test;
step four, closing a front door of the test box, enabling a sealing strip on the test box to be in contact with a panel of the slow strain rate tensile test machine through a lifting cylinder, and compressing the sealing strip to a half height;
step five, starting an air compressor, an intercooler and a test box in sequence, setting the temperature T of the test box to be 25 ℃ and the humidity phi 1 to be 5% RH;
step six, setting the strain rate v of the material slow strain rate stretching experiment to be 10 after the temperature and humidity of the test box are stable -6 mm/s, starting stretching until breaking, and obtaining the elongation after breaking A1 of the material;
step seven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step eight, repeating the steps two to four, and installing a second tensile sample;
step nine, hydrogen pressure P for examining the temperature T of the material at 25 DEG C H2 Setting the working temperature of a test box to be 25 ℃ and the humidity phi 2 to be 40%RH for the hydrogen embrittlement sensitivity under the working condition of 70 MPa;
setting a slow strain stretching rate v to be the same as that in the step six after the temperature and humidity of the test box are stable, starting stretching until the test box breaks, and testing the elongation A2 after breaking;
step eleven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step twelve, according to equation 1Calculating to obtain a hydrogen embrittlement sensitivity index I of the 7075-T6 aluminum alloy serving under 70MPa simulated hydrogen pressure;
thirteenth, repeating the steps from one to twelve for two times to obtain three hydrogen embrittlement sensitivity index test resultsComparing the average value with 10% of a reference value, and determining the hydrogen embrittlement sensitivity of the material under the working condition of 70 MPa.
1.3 Test results
(1) The A1 and A2 obtained by three repeated experiments of the 7075-T6 aluminum alloy material under 70MPa simulated hydrogen pressure and the calculated corresponding I are summarized in the following table 1.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 17%, and the average value is compared with the reference value of 10%, so that the material is determined to be sensitive to hydrogen embrittlement under the working condition of 70 MPa.
(2) According to the test scheme of example 1, a stress-strain curve of 7075-T6 aluminum alloy subjected to three repeated experiments under a 40% RH humidity condition and a 70MPa simulated hydrogen pressure test environment is obtained, and the curve is compared with a stress-strain curve obtained by 7075-T6 aluminum alloy subjected to three repeated experiments under an actual 70MPa hydrogen pressure environment, and the result is shown in FIG. 2. The left plot in FIG. 2 shows that the 7075-T6 aluminum alloy has a tensile strain rate v of 10 at a temperature of 25 ℃, a humidity of 40% RH of phi 2 -6 Stress-strain curves obtained by repeating the experiment for three times under the test condition of mm/s (corresponding to the simulated hydrogen pressure of 70 MPa); the right graph in fig. 2 shows stress-strain curves obtained by three repeated experiments of 7075-T6 aluminum alloy in an actual 70MPa hydrogen pressure environment. By comparison, the left and right graphs can be found to have higher anastomosis degree, and the reliability of the high-hydrogen environment simulation is proved.
Example 2
2.1 Experimental system
In example 2, the experimental system for simulating the hydrogen embrittlement sensitivity of the aluminum alloy material under the high-pressure hydrogen environment comprises:
the slow strain rate tensile testing machine mainly comprises a control cabinet and a host unit, wherein the host unit comprises a bearing frame, a loading unit, a deformation measuring device, a table panel, a pull rod, a sample clamp, a reaction frame and the like;
the clamp and the tensile sample are matched with the slow strain rate tensile testing machine, the clamp is a plate clamp with the thickness of 1mm, the tensile sample is an aluminum alloy material tensile test piece with the thickness of 1mm, and the tensile sample is connected with the two clamps through two round hole bolts;
the high-low temperature alternating damp-heat test box matched with the slow strain rate tensile testing machine has the main functions of providing a temperature and humidity change environment, and comprises an air dryer, a heater, a refrigeration evaporator and a blower fan so as to ensure the temperature and humidity requirements of a working chamber. The high-low temperature alternating damp-heat test box body is provided with a lifting cylinder and universal casters, can be pushed between two upright posts of the main machine of the slow strain rate tensile testing machine, and enables a top sealing strip of the high-low temperature alternating damp-heat test box body to be in contact seal with a table panel of the slow strain rate tensile testing machine through the lifting cylinder. The temperature range of the high-low temperature alternating damp-heat test box is normal temperature-100 ℃, the humidity range is 5-98% RH, the temperature fluctuation degree is less than or equal to +/-0.5 ℃, and the temperature uniformity is +/-2 ℃;
the air compressor is used for manufacturing compressed air for the high-low temperature alternating humidity and heat test box and is a novel rotary air compressor;
and the intercooler is used for providing subsequent gas cooling treatment for the air compressor.
The slow strain rate tensile testing machine and the high-low temperature alternating damp-heat testing box are arranged in a laboratory; the air compressor and the intercooler are arranged at the dry ventilation position outside the laboratory.
2.2 Test method
The hydrogen embrittlement sensitivity test of the aluminum alloy material in the simulated high-pressure hydrogen environment is carried out according to the following steps:
step one, processing a 7075-T6 aluminum alloy plate into a1 mm-thick tensile test piece 2, wherein the tensile test piece is 116mm in length, 24mm in length at the parallel end, and a round hole with the diameter of 10mm is respectively arranged between the clamping ends at the two ends, and the distance between the two circle centers is 84mm. Carrying out local polishing and ultrasonic cleaning on the parallel end of the sample until the surface roughness of the sample is less than 0.3 mu m;
step two, starting a slow strain rate tensile testing machine, and pushing a test box into a space between two upright posts of a main machine of the slow strain rate tensile testing machine;
step three, opening a front door of the test box, and installing a first tensile sample to ensure that the stress direction of the sample is consistent with the loading direction of a mechanical force value of the slow strain rate tensile test;
step four, closing a front door of the test box, enabling a sealing strip on the test box to be in contact with a panel of the slow strain rate tensile test machine through a lifting cylinder, and compressing the sealing strip to a half height;
step five, starting an air compressor, an intercooler and a test box in sequence, setting the temperature T of the test box to be 25 ℃ and the humidity phi 1 to be 5% RH;
step six, setting the strain rate v of the material slow strain rate stretching experiment to be 10 after the temperature and humidity of the test box are stable -6 mm/s, starting stretching until breaking, and obtaining the elongation after breaking A1 of the material;
step seven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step eight, repeating the steps two to four, and installing a second tensile sample;
step nine, hydrogen pressure P for examining the temperature T of the material at 25 DEG C H2 Setting the working temperature of a test box to be 25 ℃ and the humidity phi 2 to be 50% RH for the hydrogen embrittlement sensitivity under the working condition of 87.5 MPa;
setting a slow strain stretching rate v to be the same as that in the step six after the temperature and humidity of the test box are stable, starting stretching until the test box breaks, and testing the elongation A2 after breaking;
step eleven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step twelve, according to equation 1Calculating to obtain a hydrogen embrittlement sensitivity index I of the 7075-T6 aluminum alloy serving under the simulated hydrogen pressure of 87.5 MPa;
thirteenth, repeating the steps from one to twelve for two times to obtain three hydrogen embrittlement sensitivity index test resultsComparing the average value with 10% of a reference value, and determining the hydrogen embrittlement sensitivity of the material under the working condition of 87.5 MPa.
2.3 Test results
The A1 and A2 obtained by three repeated experiments of the 7075-T6 aluminum alloy material under the simulated hydrogen pressure of 87.5 MPa and the calculated corresponding I are summarized in the following table 2.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 36%, and the average value is compared with the reference value of 10%, so that the material is determined to be sensitive to hydrogen embrittlement under the working condition of 87.5 MPa.
Example 3
3.1 Experimental system
In example 3, the experimental system for simulating the hydrogen embrittlement sensitivity of the aluminum alloy material under the high-pressure hydrogen environment comprises:
the slow strain rate tensile testing machine mainly comprises a control cabinet and a host unit, wherein the host unit comprises a bearing frame, a loading unit, a deformation measuring device, a table panel, a pull rod, a sample clamp, a reaction frame and the like;
the clamp and the tensile sample are matched with the slow strain rate tensile testing machine, the clamp is a plate clamp with the thickness of 1mm, the tensile sample is an aluminum alloy material tensile test piece with the thickness of 1mm, and the tensile sample is connected with the two clamps through two round hole bolts;
the high-low temperature alternating damp-heat test box matched with the slow strain rate tensile testing machine has the main functions of providing a temperature and humidity change environment, and comprises an air dryer, a heater, a refrigeration evaporator and a blower fan so as to ensure the temperature and humidity requirements of a working chamber. The high-low temperature alternating damp-heat test box body is provided with a lifting cylinder and universal casters, can be pushed between two upright posts of the main machine of the slow strain rate tensile testing machine, and enables a top sealing strip of the high-low temperature alternating damp-heat test box body to be in contact seal with a table panel of the slow strain rate tensile testing machine through the lifting cylinder. The temperature range of the high-low temperature alternating damp-heat test box is normal temperature-100 ℃, the humidity range is 5-98% RH, the temperature fluctuation degree is less than or equal to +/-0.5 ℃, and the temperature uniformity is +/-2 ℃;
the air compressor is used for manufacturing compressed air for the high-low temperature alternating humidity and heat test box and is a novel rotary air compressor;
and the intercooler is used for providing subsequent gas cooling treatment for the air compressor.
The slow strain rate tensile testing machine and the high-low temperature alternating damp-heat testing box are arranged in a laboratory; the air compressor and the intercooler are arranged at the dry ventilation position outside the laboratory.
3.2 Test method
The hydrogen embrittlement sensitivity test of the aluminum alloy material in the simulated high-pressure hydrogen environment is carried out according to the following steps:
step one, processing a 7075-T6 aluminum alloy plate into a1 mm-thick tensile test piece 2, wherein the tensile test piece is 116mm in length, 24mm in length at the parallel end, and a round hole with the diameter of 10mm is respectively arranged between the clamping ends at the two ends, and the distance between the two circle centers is 84mm. Carrying out local polishing and ultrasonic cleaning on the parallel end of the sample until the surface roughness of the sample is less than 0.3 mu m;
step two, starting a slow strain rate tensile testing machine, and pushing a test box into a space between two upright posts of a main machine of the slow strain rate tensile testing machine;
step three, opening a front door of the test box, and installing a first tensile sample to ensure that the stress direction of the sample is consistent with the loading direction of a mechanical force value of the slow strain rate tensile test;
step four, closing a front door of the test box, enabling a sealing strip on the test box to be in contact with a panel of the slow strain rate tensile test machine through a lifting cylinder, and compressing the sealing strip to a half height;
step five, starting an air compressor, an intercooler and a test box in sequence, setting the temperature T of the test box to be 25 ℃ and the humidity phi 1 to be 5% RH;
step six, waitingAfter the temperature and humidity of the test box are stable, setting the strain rate v of the material slow strain rate stretching test to be 10 -6 mm/s, starting stretching until breaking, and obtaining the elongation after breaking A1 of the material;
step seven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step eight, repeating the steps two to four, and installing a second tensile sample;
step nine, hydrogen pressure P for examining the temperature T of the material at 25 DEG C H2 Setting the working temperature of a test box to be 25 ℃ and the humidity phi 2 to be 60%RH for the hydrogen embrittlement sensitivity under the working condition of 105 MPa;
setting a slow strain stretching rate v to be the same as that in the step six after the temperature and humidity of the test box are stable, starting stretching until the test box breaks, and testing the elongation A2 after breaking;
step eleven, opening a front door of the test box, taking out a sample, observing fracture tissues of the sample, and finding out the initiation and the expansion of brittle cracks in the fracture tissues, thereby judging that hydrogen embrittlement fracture occurs;
step twelve, according to equation 1Calculating to obtain a hydrogen embrittlement sensitivity index I of the 7075-T6 aluminum alloy serving under the simulated hydrogen pressure of 105 MPa;
thirteenth, repeating the steps from one to twelve for two times to obtain three hydrogen embrittlement sensitivity index test resultsComparing the average value with 10% of a reference value, and determining the hydrogen embrittlement sensitivity of the material under the working condition of 105 MPa.
3.3 Test results
The A1 and A2 obtained by three repeated experiments of the 7075-T6 aluminum alloy material under the simulated hydrogen pressure of 105MPa and the calculated corresponding I are summarized in the following table 3.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 57%, and the average value is compared with a reference value of 10%, so that the material is determined to be sensitive to hydrogen embrittlement under the working condition of 105 MPa.
Example 4
Another aluminum alloy material, 6061-T6 aluminum alloy, was tested for hydrogen embrittlement sensitivity under 70MPa simulated hydrogen pressure using the same experimental system and test method as in example 1.
The A1 and A2 obtained by three repeated experiments of 6061-T6 aluminum alloy material under 70MPa simulated hydrogen pressure and the calculated corresponding I are summarized in the following table 4.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 3%, and compared with the reference value of 10%, the 6061-T6 aluminum alloy material is determined to be insensitive to hydrogen embrittlement under the working condition of 70 MPa.
Example 5
Another aluminum alloy material, 6061-T6 aluminum alloy, was tested for hydrogen embrittlement sensitivity under simulated hydrogen pressure at 87.5 MPa using the same experimental system and test method as in example 2.
The A1 and A2 obtained by three repeated experiments of 6061-T6 aluminum alloy material under the simulated hydrogen pressure of 87.5 MPa and the calculated corresponding I are summarized in the following table 5.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 7%, and compared with the reference value of 10%, the 6061-T6 aluminum alloy material is determined to be insensitive to hydrogen embrittlement under the working condition of 87.5 MPa.
Example 6
Another aluminum alloy material, 6061-T6 aluminum alloy, was tested for sensitivity to hydrogen embrittlement under simulated hydrogen pressure at 105MPa using the same experimental system and test method as in example 3.
The A1 and A2 obtained by three repeated experiments of 6061-T6 aluminum alloy material under the simulated hydrogen pressure of 105MPa and the calculated corresponding I are summarized in the following table 6.
By calculation, three hydrogen embrittlement sensitivity index test resultsThe average value of (2) is 9%, and compared with the reference value of 10%, the 6061-T6 aluminum alloy material is determined to be insensitive to hydrogen embrittlement under the working condition of 105 MPa.
The method disclosed by the invention can be used for testing the hydrogen embrittlement sensitivity of the aluminum alloy material in a simulated high-pressure hydrogen environment with the pressure of more than 70MPa, and has the obvious advantages of small equipment investment, safe and reliable test, simple operation, short test period and the like.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A method of testing the susceptibility of an aluminum alloy material to hydrogen embrittlement in a simulated high pressure hydrogen environment, the method comprising:
s1: at a temperature T and a first humidity phi 1, carrying out first time on the aluminum alloy material at a strain rate vA slow strain rate stretching experiment is carried out to obtain a first elongation after break A1, wherein the temperature T is 20-35 ℃, the first humidity phi 1 is 0-10% RH, and the strain rate v is 10 -7 ~10 -6 mm/s；
S2: carrying out a second slow strain rate stretching experiment on the aluminum alloy material at the strain rate v at the temperature T and a second humidity phi 2 to obtain a second after-break elongation A2 under the simulated high-pressure hydrogen environment, wherein the second humidity phi 2 is 40% -60% RH, and the simulated hydrogen pressure P simulating the high-pressure hydrogen environment H2 70-105 MPa;
s3: according to the following formula 1, calculating the hydrogen embrittlement sensitivity index I of the aluminum alloy material under the simulated high-pressure hydrogen environment,
equation 1: i= (A1-A2)/a1×100%;
s4: comparing the hydrogen embrittlement sensitivity index I with a reference value of 10%, if the hydrogen embrittlement sensitivity index I is more than or equal to 10%, determining that the aluminum alloy material is hydrogen embrittlement-sensitive in the simulated high-pressure hydrogen environment, and if the hydrogen embrittlement sensitivity index I is less than 10%, determining that the aluminum alloy material is hydrogen embrittlement-insensitive in the simulated high-pressure hydrogen environment.
2. The method of claim 1, wherein the temperature T is 25 ℃.
3. The method of claim 1, wherein the first humidity Φ1 is 5% rh.
4. The method of claim 1, wherein the second humidity Φ2 is 40% rh.
5. The method of claim 1, wherein the second humidity Φ2 is 50% rh.
6. The method of claim 1, wherein the second humidity Φ2 is 60% rh.
7. According toThe method of claim 1, wherein the temperature T is 25 ℃, the second humidity Φ2 is 40% rh, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 70 MPa.
8. The method of claim 1, wherein the temperature T is 25 ℃, the second humidity Φ2 is 50% rh, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 87.5 MPa.
9. The method of claim 1, wherein the temperature T is 25 ℃, the second humidity Φ2 is 60% rh, and the simulated hydrogen pressure P simulates a high pressure hydrogen environment H2 105 MPa.
10. The method according to any one of claims 1 to 9, characterized in that before step S1, the method further comprises the steps of: polishing and ultrasonic cleaning are carried out on the aluminum alloy material.
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