Testing method for intergranular corrosion resistance of aluminum alloy

Abstract

The present invention provides a method for testing the intergranular corrosion resistance of an aluminum alloy, the method comprising: obtaining a first sample group and a second sample group from an aluminum alloy plate to be tested; placing the first sample group and the second sample group in the same test solution for intergranular corrosion; removing the first sample group and the second sample group after a target time, and obtaining the mass loss per unit area of ​​the first sample group and the intergranular corrosion depth of the second sample group; and obtaining a correlation between the mass loss per unit area and the intergranular corrosion depth. The method of the present invention determines that the intergranular corrosion resistance of an aluminum alloy material can be predicted by the mass loss of the aluminum alloy material during the intergranular corrosion process and the corrosion depth, and establishes a linear relationship between the two. The method is suitable for testing the intergranular corrosion resistance of various aluminum alloy materials, and the detection process is simple, controllable, and highly practical.

Description

Technical Field

[0001] The present invention relates to the technical field of alloy materials, and in particular to a method for detecting the intergranular corrosion resistance of aluminum alloys. Background Art

[0002] Aluminum alloy materials are ideal materials for lightweight transportation due to their high strength, good impact resistance and abundant reserves. They are often used in the manufacture of rail transit vehicle bodies.

[0003] Intergranular corrosion refers to electrochemical localized corrosion caused by the inconsistency of solute elements inside and outside aluminum alloys and the uneven distribution of microstructures. The evaluation method of the intergranular corrosion resistance of aluminum alloy materials in related technologies is relatively rough, resulting in inaccurate evaluation results. Summary of the Invention

[0004] The present invention provides a method for detecting the intergranular corrosion resistance of aluminum alloys, which is used to solve the defect of the prior art that only mass loss is used to detect the intergranular corrosion resistance of aluminum alloy materials, the detection means is single, and the detection results are inaccurate, thereby improving the accuracy of the evaluation of the intergranular corrosion resistance of aluminum alloys.

[0005] The present invention provides a method for detecting the intergranular corrosion resistance of an aluminum alloy, comprising:

[0006] Obtaining a first sample group and a second sample group from the aluminum alloy plate to be tested;

[0007] Placing the first sample group and the second sample group in the same test solution for intergranular corrosion;

[0008] After a target time, the first sample group and the second sample group are taken out, and the mass loss per unit area of ​​the first sample group and the intergranular corrosion depth of the second sample group are obtained;

[0009] A correlation between the mass loss per unit area and the intergranular corrosion depth is obtained, and the mass loss per unit area is used to determine the intergranular corrosion resistance of the aluminum alloy plate to be tested.

[0010] According to a method for testing the intergranular corrosion resistance of aluminum alloy provided by the present invention, the first sample group and the second sample group are placed in the same test solution for intergranular corrosion, comprising:

[0011] The first sample group is suspended and immersed in the test solution, while the second sample group with the target surface exposed and other surfaces except the target surface covered is placed flat in the test solution.

[0012] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, obtaining the mass loss of samples in the first sample group includes:

[0013] measuring the mass of the samples each time the particles adhering to the surfaces of the samples in the first sample group are cleaned;

[0014] When the mass difference between two adjacent measurements of the sample is less than a target threshold, the mass loss of the sample in the first sample group is determined based on the difference between the mass of the sample measured second to last and the initial mass of the sample.

[0015] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, obtaining the intergranular corrosion depth of the second sample group includes:

[0016] Obtaining a target cross section of each sample in the second sample group, wherein the target cross section is obtained by cutting each sample in the second sample group along a direction perpendicular to the rolling direction;

[0017] Performing metallographic sample preparation on the target cross section to obtain a metallographic sample;

[0018] A metallographic image corresponding to the metallographic sample is obtained based on a metallographic microscope, and the intergranular corrosion depth is obtained from the metallographic image.

[0019] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, obtaining the intergranular corrosion depth from the metallographic image comprises:

[0020] Based on scanning electron microscopy and electron backscatter diffraction, a target area where the intergranular corrosion occurs in the metallographic image is determined, and the depth of the intergranular corrosion is measured in the target area.

[0021] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, obtaining the mass loss per unit area of ​​the first sample group includes:

[0022] The mass loss of the samples in the first sample group is obtained, and the mass loss per unit area is obtained based on the ratio of the mass loss of the samples to the surface area of ​​the corresponding samples.

[0023] According to a method for testing the intergranular corrosion resistance of aluminum alloy provided by the present invention, the test solution is a mixed solution of sodium chloride and hydrogen chloride, wherein the concentration range of the sodium chloride is 20g / L-100g / L, and the concentration range of the hydrogen chloride is 5ml / L-20ml / L.

[0024] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, the temperature range of the test solution is 25°C-90°C.

[0025] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, the target time range is 12h-200h.

[0026] According to a method for detecting intergranular corrosion resistance of aluminum alloy provided by the present invention, obtaining a first sample group and a second sample group from the aluminum alloy plate to be tested comprises:

[0027] Cutting the aluminum alloy plate to be tested to obtain a plurality of aluminum alloy blocks, and dividing the plurality of aluminum alloy blocks into two groups, respectively obtaining a first sample aluminum alloy and a second sample aluminum alloy;

[0028] The exposed surfaces of the first sample aluminum alloy and the exposed surfaces of the second sample aluminum alloy are polished, and the first sample aluminum alloy is cleaned to obtain the first sample group, and the second sample aluminum alloy is cleaned to obtain the second sample group.

[0029] The method for detecting the intergranular corrosion resistance of aluminum alloys provided by the present invention obtains the mass loss and corrosion depth of the aluminum alloy material during the intergranular corrosion process and establishes a linear relationship between the two, thereby determining the intergranular corrosion resistance of the aluminum alloy material based on the mass loss during the corrosion process. The method is suitable for detecting the intergranular corrosion resistance of various aluminum alloy materials, and its detection process is simple, controllable, and highly practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 1 is a flow chart of a method for detecting intergranular corrosion resistance of aluminum alloys provided by the present invention;

[0032] Figure 2 This is one of the interface schematic diagrams of the mass loss per unit area of ​​the aluminum alloy provided by the present invention;

[0033] Figure 3 This is the second interface schematic diagram of the mass loss per unit area of ​​the aluminum alloy provided by the present invention;

[0034] Figure 4 This is one of the schematic diagrams of the corrosion depth of the aluminum alloy corrosion cross section provided by the present invention;

[0035] Figure 5 This is the second schematic diagram of the corrosion depth of the aluminum alloy corrosion cross section provided by the present invention;

[0036] Figure 6This is one of the correlation line graphs between the mass loss per unit area of ​​aluminum alloy and the corrosion depth provided by the present invention;

[0037] Figure 7 This is the second correlation line graph between the mass loss per unit area of ​​aluminum alloy and the corrosion depth provided by the present invention;

[0038] Figure 8 This is one of the interface images of the metallographic image of the aluminum alloy provided by the present invention under SEM;

[0039] Figure 9 This is the second interface image of the metallographic image of the aluminum alloy provided by the present invention under SEM. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0041] The following combination Figure 1 The present invention provides a method for detecting the intergranular corrosion resistance of aluminum alloys, including:

[0042] Step 110: Obtain a first sample group and a second sample group from the aluminum alloy plate to be tested.

[0043] In this step, the aluminum alloy plate to be tested may be a 6xxx series aluminum alloy material, or may be a 5xxx series or 7xxx series aluminum alloy plate.

[0044] In this step, the first sample group and the second sample group can be a collection of multiple identical aluminum alloy samples. The aluminum alloy samples in the first sample group and the aluminum alloy samples in the second sample group can be completely identical, or they can be the same in shape but different in size.

[0045] In this embodiment, the sizes of the aluminum alloy samples in the first sample group and the second sample group can be customized according to actual needs. For example, the size of each sample in the first sample group and the second sample group is uniformly set to 20cm×40cm×4cm, or the size of each sample in the first sample group can be set to 20cm×40cm×4cm, and the size of each sample in the second sample group can be uniformly set to 20cm×20cm×4cm.

[0046] In this embodiment, a plurality of aluminum alloy samples with a size of 20 cm×40 cm×4 cm are cut from a 6xxx series aluminum alloy material, and the aluminum alloy samples are evenly divided into two groups to obtain a first sample group and a second sample group.

[0047] Step 120: Place the first sample group and the second sample group in the same test solution for intergranular corrosion.

[0048] In this step, the test solution is a reaction solution for the sample to undergo intergranular corrosion, for example, a mixed solution of sodium chloride and sodium chloride.

[0049] In this step, the first sample group and the second sample group can be placed in two identical test solutions respectively to carry out the intergranular corrosion process of the aluminum alloy, or the first sample group and the second sample group can be placed in one sufficient test solution to carry out the intergranular corrosion process of the aluminum alloy.

[0050] In this embodiment, the ambient temperature of the test solution can be kept constant, for example, 25° C., or can be customized and adjusted according to actual needs.

[0051] In some embodiments, each sample in the first sample group can be clamped and completely placed in the test solution using clamps that do not cause intergranular corrosion with the test solution. Alternatively, holes can be punched in each sample in the first sample group so that the first sample can be suspended and immersed in the test solution through the holes in a subsequent process. After polishing, cleaning impurities, and other operations are performed on each sample in the second sample group and the punched first sample group, the initial mass of each sample in the first sample group and the second sample group is weighed using an instrument such as a balance. For example, the initial mass of a sample measured using a balance is 10.05 g.

[0052] In this embodiment, after the initial mass of each sample in the first sample group and the second sample group is measured, each sample in the first sample group can be suspended with a thin rope and immersed in one test solution, and the non-corrosion surface of each sample in the second sample group can be sealed so that only the corrosion surface is exposed and then placed flat in another identical test solution.

[0053] In this embodiment, the corrosion surface of the sample can be any one surface or multiple surfaces of the above-mentioned aluminum alloy sample, and the non-corrosion surface is the other surface of the sample except the corrosion surface.

[0054] exist Figure 2-Figure 3 In the embodiment shown, Figure 2 The surface corrosion changes of the samples in the first sample group at different time periods in the test solution at 35°C are shown. Figure 2 (a)- Figure 2The corrosion times corresponding to (k) are 0h, 24h, 36h, 48h, 60h, 72h, 84h, 96h, 108h, 120h, and 144h, respectively. Figure 2 It can be seen that: at the same temperature, as the reaction time increases, the surface corrosion degree of the sample gradually deepens; Figure 3 The surface corrosion changes of the samples in the first sample group at different time periods in the test solution at 50°C are shown. Figure 3 (a)- Figure 3 (d) The corresponding corrosion times are 12h, 24h, 36h, and 48h, respectively. Figure 3 It can be seen that: at the same temperature, as the reaction time increases, the surface corrosion degree of the sample gradually deepens; Figure 2-Figure 3 Comparing the surface corrosion changes of the aluminum alloys shown under the same reaction time, it can be seen that the surface corrosion degree of each sample in the first sample group can be deepened when the temperature is higher.

[0055] exist Figure 4-Figure 5 In the embodiment shown, Figure 4 The internal corrosion changes of the samples in the second sample group at different time periods in the test solution at 35°C are shown. Figure 4 It can be seen that: at the same temperature, as the reaction time increases, the internal corrosion degree of the sample gradually deepens; Figure 5 The internal corrosion changes of the samples in the second sample group at different time periods in the test solution at 50℃ are shown. Figure 5 It can be seen that: at the same temperature, as the reaction time increases, the internal corrosion degree of the sample gradually deepens; Figures 4 and 5 Comparison of the internal corrosion changes at the same reaction time shows that a higher temperature can deepen the degree of internal corrosion of each sample in the second sample group.

[0056] Combine Figure 2-Figure 5 From the changes in surface corrosion and internal corrosion of the samples, it can be seen that during the intergranular corrosion of aluminum alloy materials, the surface corrosion changes and corrosion depth changes of the aluminum alloy materials are consistent with the increase of reaction time and reaction temperature.

[0057] In some embodiments, the ratio of the exposed area of ​​the samples in the first sample group to the volume of the test solution and the ratio of the exposed area of ​​the samples in the second sample group to the volume of the test solution do not exceed a set threshold value, which can be customized. For example, the set threshold value can be 20 mm. 2 / mL.

[0058] Step 130: After the target time, the first sample group and the second sample group are taken out, and the mass loss per unit area of ​​the first sample group and the intergranular corrosion depth of the second sample group are obtained; the correlation between the mass loss per unit area and the intergranular corrosion depth is obtained, and the mass loss per unit area is used to determine the intergranular corrosion resistance of the aluminum alloy plate to be tested.

[0059] In this step, the target duration is the duration for each sample in the first sample group and the second sample group to undergo intergranular corrosion reaction in the test solution, which can be determined by the aluminum alloy material, the concentration of the test solution, and the test temperature.

[0060] In this step, the mass loss per unit area of ​​the first sample group is the ratio of the total mass loss of each sample in the first sample group after intergranular corrosion occurs to the surface area of ​​the sample, and the intergranular corrosion depth of the second sample group represents the corrosion distribution obtained on the internal cross-section of each sample in the second sample group after intergranular corrosion occurs.

[0061] In this step, the correlation between the mass loss per unit area and the intergranular corrosion depth refers to a linear relationship obtained by fitting multiple sets of average mass loss data and intergranular corrosion depth data. This correlation can reflect the changing trend of mass loss and corrosion depth when intergranular corrosion occurs in aluminum alloys.

[0062] In this embodiment, the corrosion surface of the first sample group is all external surfaces. After the first sample group is taken out from the test solution, the mass of each sample is measured by a balance to obtain a mass loss value, and the ratio of the mass loss value of the sample to its surface area is calculated to obtain the mass loss per unit area of ​​the first sample group. The corrosion surface of the second sample group is one external surface. After the other surfaces except the external surface are coated and placed in the test solution for reaction, the second sample group is taken out and the samples in the second sample group are cut to obtain a cross-sectional view. The intergranular corrosion depth of the sample can be obtained from the cross-sectional view. After performing multiple groups of tests, multiple groups of mass loss data per unit area and intergranular corrosion depth data are obtained. Based on the above multiple groups of data, a linear relationship between the mass loss data and the intergranular corrosion depth can be analyzed.

[0063] exist Figure 6-Figure 7 In the embodiment shown, Figure 6 The graph shows the change in mass loss per unit area of ​​the first sample group when intergranular corrosion occurs in the test solution at 35°C, that is, the change in mass loss per unit area of ​​each sample in the first sample group in the test solution at 35°C with corrosion time. The graph also shows the change in corrosion depth of the second sample group when intergranular corrosion occurs in the test solution at 35°C, that is, the change in corrosion depth of each sample in the second sample group in the test solution at 35°C with corrosion time. Figure 6It can be seen that in the test solution at 35°C, with the increase of corrosion time, the surface corrosion changes and corrosion depth changes of aluminum alloy materials are consistent; Figure 7 The changes in mass loss per unit area and corrosion depth of the first and second sample groups when intergranular corrosion occurred in the test solution at 50°C are shown. Figure 7 It can be seen that in the test solution at 50°C, with the increase of corrosion time, the surface corrosion changes and corrosion depth changes of the aluminum alloy material are consistent.

[0064] Combine Figure 6-Figure 7 From the changes in surface corrosion and internal corrosion of the samples, it can be seen that during the intergranular corrosion of aluminum alloy materials, the changes in mass loss per unit area and corrosion depth of the aluminum alloy materials are consistent with the increase of reaction time and reaction temperature.

[0065] According to the method for detecting the intergranular corrosion resistance of aluminum alloys provided in the embodiments of the present application, by obtaining the mass loss and corrosion depth of the aluminum alloy material during the intergranular corrosion process and establishing a linear relationship between the two, it is determined that the intergranular corrosion resistance of the aluminum alloy material can be predicted by the mass loss of the aluminum alloy material during the corrosion process. The method is suitable for detecting the intergranular corrosion resistance of various aluminum alloy materials, and its detection process is simple, controllable, and highly practical.

[0066] In some embodiments, the first sample group and the second sample group are placed in the same test solution for intergranular corrosion, including: suspending the first sample group and immersing it in the test solution, while placing the second sample group with the target surface exposed and other surfaces except the target surface covered flat in the test solution.

[0067] In this embodiment, the first sample group is used to detect the mass change when intergranular corrosion occurs between the aluminum alloy and the test solution. The outer surfaces of all samples in the first sample group are exposed to fully contact the test solution. The second sample group is used to detect the change in corrosion depth when intergranular corrosion occurs between the aluminum alloy and the test solution. Only one outer surface of the second sample group can be exposed, and the other outer surfaces can be coated. This can avoid excessive exposure of the outer surface of the aluminum alloy and the corrosion process of the first sample group in the test solution.

[0068] In this embodiment, the first sample group is suspended and immersed in the test solution by opening a hole in each sample in the first sample group, such as Figure 2 As shown, the samples in the first sample group are then immersed in the test solution in a suspended manner using the holes.

[0069] In this embodiment, the material used to coat the non-corrosion surface of the aluminum alloy is used to isolate the non-corrosion surface from contact with the test solution and intergranular corrosion, for example, a composite material containing chromium and niobium; the non-corrosion surface of the aluminum alloy can also be coated by rosin sealing or the like.

[0070] In this embodiment, each sample in the first sample group is suspended through an opening and immersed in a test solution, and each sample in the second sample group is placed flat in the same test solution with only one corrosion surface exposed and the non-corrosion surface coated.

[0071] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, by making all the outer surfaces of the samples in the first sample group fully contact with the reaction solution, more accurate mass loss data per unit area can be obtained, and by making only the corroded surface of the samples in the second sample group fully contact with the reaction solution, corrosion depth data can be obtained, providing a reliable data source for subsequent acquisition of the correlation between mass loss per unit area and corrosion depth.

[0072] In some embodiments, obtaining the mass loss of samples in the first sample group includes: measuring the mass of the samples each time the adhered particles on the surface of the samples in the first sample group are cleaned; and determining the mass loss of the samples in the first sample group based on the difference between the mass of the samples measured second to last and the initial mass of the samples when the difference between the masses of the samples measured two adjacent times is less than a target threshold.

[0073] It should be noted that since impurities may adhere to the surface of the samples in the first sample group just taken out, there will be errors in directly weighing the samples and calculating the mass loss before and after intergranular corrosion, which may lead to a large deviation in the calculation results of the mass loss per unit area of ​​the samples.

[0074] In this embodiment, the surfaces of the samples in the first sample group just taken out are washed with clean water and a brush to reduce impurities adhering to the surfaces of the samples.

[0075] In this embodiment, after each cleaning of the sample, it is dried and weighed until the difference between the weighings of two adjacent samples is less than the target threshold, the cleaning is considered complete, and the difference between the weighing result of the penultimate sample and the initial mass of the sample is used as the mass loss of the sample; wherein, the target threshold can be customized according to actual needs, for example, the range of the target threshold can be set between 0.1mg-1.0mg.

[0076] In some embodiments, after obtaining the mass loss of the sample through the above embodiment, the mass loss per unit area of ​​the sample X is calculated using the following formula:

[0077]

[0078] Where n is a natural number greater than 1, m1 is the initial mass of the sample, and m n-1 is the mass of the sample measured at the second to last time, and s is the exposed area of ​​the sample.

[0079] In this embodiment, after the first sample group is removed after the target time, the samples in the first sample group are rinsed with water and scrubbed with a hard plastic brush to remove all adhering particles, and then air-dried. The dried samples are weighed on a balance until the difference between two consecutive weighing results is less than 0.5 mg. The difference between the penultimate sample weighing result and the initial mass of the sample is used as the mass loss of the sample, and the weight loss per unit area is calculated.

[0080] In some embodiments, the final mass loss per unit area may be obtained by rounding off the average of the mass loss per unit area of ​​the samples calculated continuously.

[0081] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, the accuracy of experimental data calculation can be improved by calculating the mass loss of the samples after removing impurities adhered to the surface of the samples in the first sample group.

[0082] In some embodiments, obtaining the intergranular corrosion depth of the second sample group includes: obtaining a target cross-section of each sample in the second sample group, where the target cross-section is obtained by cutting each sample in the second sample group along a direction perpendicular to the rolling direction; performing metallographic sample preparation on the target cross-section to obtain a metallographic sample; obtaining a metallographic image corresponding to the metallographic sample based on a metallographic microscope, and obtaining the intergranular corrosion depth from the metallographic image.

[0083] In this embodiment, the target cross section includes the corrosion depth distribution information of the sample. After the cross section is metallographically prepared, the corrosion depth information included in the sample cross section can be obtained using equipment such as a Venus microscope.

[0084] In this embodiment, when the samples in the second sample group were removed from the test solution, they were cut along the direction perpendicular to the rolling direction to obtain a cross-section of the sample. The cross-section was then subjected to metallographic sample preparation in accordance with GBT 3246.2-2012, Method for Microstructure Inspection of Deformed Aluminum and Aluminum Alloy Products, to obtain a metallographic image. The metallographic sample was then observed using an OLYSIM Basic metallographic microscope, and the metallographic image was captured. Finally, the corrosion depth of the sample was measured from the metallographic image.

[0085] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, by performing metallographic sampling on the cross-section of the samples in the second sample group and obtaining the corresponding metallographic image, the corrosion depth data of the sample can be conveniently measured, which can be used to establish a correlation with the mass loss data per unit area of ​​the aluminum alloy.

[0086] In some embodiments, obtaining the intergranular corrosion depth from the metallographic image includes: determining a target area where intergranular corrosion occurs in the metallographic image based on scanning electron microscopy and electron backscatter diffraction, and measuring the intergranular corrosion depth in the target area.

[0087] It should be noted that after obtaining the metallographic image of the sample cross-section, the distribution of the corrosion area of ​​the sample is relatively complex due to the instability of corrosion diffusion. When directly observing and measuring the corrosion depth through the metallographic image, measurement errors may occur due to errors in human eye recognition.

[0088] In this embodiment, after obtaining the metallographic image of the sample cross section, the metallographic photograph is observed and analyzed by electron microscopy (SEM) and electron backscatter diffraction (EBSD), respectively, so that the intergranular corrosion morphology can be directly viewed and the intergranular corrosion depth can be measured based on the intergranular corrosion morphology.

[0089] exist Figure 8-Figure 9 In the embodiment shown, Figure 8 As shown, the samples in the second sample group were subjected to intergranular corrosion in the test solution at 35°C and the metallographic photographs of the samples were obtained. After the metallographic photographs of the samples were observed by SEM, it can be seen that Figure 8 The corrosion area is more clearly observed (corresponding to Figure 8 depth area in the lower middle part), so that Figure 8 Measure the distance on the map according to the scale to obtain the corresponding corrosion depth; Figure 9 As shown, the samples in the second sample group were subjected to intergranular corrosion in the test solution at 50°C and the metallographic photographs of the samples were obtained. After the metallographic photographs of the samples were observed by SEM, it can be seen that Figure 9 The corrosion area is more clearly observed (corresponding to Figure 9 lower depth area), so that it can be directly Figure 9 The distance on the diagram is measured according to the scale to obtain the corresponding corrosion depth. In addition, after analyzing the metallographic photograph through EBSD, the area where corrosion occurs can also be measured intuitively, which will not be described in detail in this embodiment.

[0090] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, by using SEM and EBSD to analyze metallographic images so as to more intuitively observe the corrosion depth of the sample, more accurate corrosion depth data is obtained, thereby improving the accuracy of the experimental results.

[0091] In some embodiments, obtaining the mass loss per unit area of ​​the first sample group includes: obtaining the mass loss of samples in the first sample group, and obtaining the mass loss per unit area based on a ratio of the mass loss of the samples to the surface area of ​​the corresponding samples.

[0092] In this embodiment, when the samples in the first sample group are taken out from the test solution after the target time, the mass of the sample at the current moment is measured using a weighing instrument such as a balance, and the mass loss value of the sample during the intergranular corrosion process is obtained by performing a difference operation with the initial mass of the sample. The mass loss per unit area of ​​the sample during the intergranular corrosion process is then calculated using the sample surface area obtained in advance.

[0093] In this embodiment, the samples in the first sample group may be arranged as spheres or cubes with regular shapes.

[0094] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, the mass loss of aluminum alloy per unit area is obtained by calculating the ratio of the mass loss of aluminum alloy after intergranular corrosion to the exposed area of ​​aluminum alloy, which can be used to establish a correlation with the corrosion depth of aluminum alloy obtained in subsequent processes.

[0095] In some embodiments, the test solution is a mixed solution of sodium chloride and hydrogen chloride, wherein the concentration of sodium chloride ranges from 20 g / L to 100 g / L, and the concentration of hydrogen chloride ranges from 5 ml / L to 20 ml / L.

[0096] It should be noted that, since 6xxx series aluminum alloy materials have certain corrosion resistance, in order to ensure the efficiency of the intergranular corrosion process, the concentration of each component in the test solution needs to be configured in proportion.

[0097] In this embodiment, the test solution for intergranular corrosion with aluminum alloy may be a mixed solution of 57 g / L sodium chloride and 10 ml / L hydrogen chloride.

[0098] Of course, in other embodiments, the concentration of each component in the test solution is set according to actual needs. For example, a test solution with a suitable concentration is prepared according to factors such as sample size, ambient temperature, and reagent cost.

[0099] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, by setting a test solution of appropriate concentration, the intergranular corrosion process of the aluminum alloy in the test solution can be effectively occurred.

[0100] In some embodiments, the temperature of the test solution ranges from 25°C to 90°C.

[0101] It should be noted that since 6xxx series aluminum alloy materials have certain corrosion resistance, after preparing a test solution of appropriate concentration, the ambient temperature of the test solution can be increased to enhance the expansion of intergranular corrosion.

[0102] In this embodiment, an aluminum alloy and a test solution containing 57 g / L sodium chloride and 10 ml / L hydrogen chloride are placed in a constant temperature water bath. The ambient temperature is regulated by the constant temperature water bath so that the temperature at which the intergranular corrosion process occurs between the aluminum alloy and the test solution is maintained at a constant temperature. For example, the temperature of the test solution can be 35°C or 50°C. The test solution can also be maintained within a certain temperature range. For example, the temperature of the test solution can also be 50°C±2°C.

[0103] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, the intergranular corrosion process of the aluminum alloy in the test solution can be accelerated by setting and regulating the temperature of the test solution.

[0104] In some embodiments, the target duration ranges from 12 hours to 200 hours.

[0105] It should be noted that in order to accelerate the intergranular corrosion of 6xxx series aluminum alloy materials in the test solution, after preparing a test solution of appropriate concentration and increasing the ambient temperature of the test solution, the degree of intergranular corrosion can also be increased by extending the immersion time of the aluminum alloy in the test solution.

[0106] exist Figure 3 In the embodiment shown, an aluminum alloy and a test solution containing 57 g / L sodium chloride and 10 ml / L hydrogen chloride are placed in a constant temperature water bath. The ambient temperature is regulated by the constant temperature water bath so that the temperature at which the intergranular corrosion process occurs between the aluminum alloy and the test solution is maintained at 50°C. Then, multiple groups of tests are performed by setting the corrosion time to 12 h, 24 h, 36 h, and 48 h, and the surface corrosion of the aluminum alloy at different corrosion times is observed.

[0107] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, the degree of intergranular corrosion of the aluminum alloy in the test solution can be improved by setting the corrosion time of the aluminum alloy and the test solution to be extended.

[0108] In some embodiments, obtaining a first sample group and a second sample group from an aluminum alloy plate to be tested includes: cutting the aluminum alloy plate to be tested to obtain a plurality of aluminum alloy blocks, and dividing the plurality of aluminum alloy blocks into two groups, respectively obtaining a first sample aluminum alloy and a second sample aluminum alloy; polishing the exposed surface of the first sample aluminum alloy and the exposed surface of the second sample aluminum alloy, and cleaning the first sample aluminum alloy to obtain the first sample group, and cleaning the second sample aluminum alloy to obtain the second sample group.

[0109] In this embodiment, the aluminum alloy plate to be tested may be a 6xxx series aluminum alloy material, or may be a 5xxx series or 7xxx series aluminum alloy plate.

[0110] In this embodiment, the polishing method can be to polish the exposed surface of the aluminum alloy with 80#, 320#, 800# and 1500# water-abrasive sandpaper, wherein all outer surfaces of the first sample aluminum alloy can be polished, and one surface of the second sample aluminum alloy can be polished, and the surface will undergo intergranular corrosion in the test solution.

[0111] In this embodiment, the cleaning method can be to wash the polished first sample aluminum alloy and the second sample aluminum alloy with ethanol, 10% concentration sodium hydroxide solution and 30% concentration nitric acid solution in turn, and dry the washed sample aluminum alloy to obtain the initial mass and exposed area of ​​the sample aluminum alloy.

[0112] According to the method for detecting the intergranular corrosion resistance of aluminum alloy provided in the embodiment of the present application, the first sample group and the second sample group are obtained by performing operations such as grinding and cleaning on the obtained aluminum alloy block, which can reduce the influence of impurities on the measurement results and improve the accuracy of the experimental data.

[0113] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, or of course, by hardware. Based on this understanding, the essence of the above technical solution or the part that contributes to the existing technology can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, an optical disk, etc., and includes a number of instructions for enabling a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or certain parts of the embodiments.

[0114] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for detecting the intergranular corrosion resistance of aluminum alloy, characterized in that: include: Obtaining a first sample group and a second sample group from the aluminum alloy plate to be tested; Placing the first sample group and the second sample group in the same test solution for intergranular corrosion; After a target time, the first sample group and the second sample group are taken out, and the mass loss per unit area of ​​the first sample group and the intergranular corrosion depth of the second sample group are obtained; Obtaining a correlation between the mass loss per unit area and the intergranular corrosion depth, wherein the mass loss per unit area is used to determine the intergranular corrosion resistance of the aluminum alloy plate to be tested; Placing the first sample group and the second sample group in the same test solution for intergranular corrosion includes: Suspending the first sample group and immersing it in the test solution, while placing the second sample group with the target surface exposed and other surfaces except the target surface covered flat in the test solution; The obtaining of the mass loss of samples in the first sample group includes: measuring the mass of the samples each time the particles adhering to the surfaces of the samples in the first sample group are cleaned; When the difference between the masses of the sample measured two adjacent times is less than a target threshold, determining the mass loss of the sample in the first sample group based on the difference between the mass of the sample measured second to last and the initial mass of the sample; Obtaining the intergranular corrosion depth of the second sample group includes: Obtaining a target cross section of each sample in the second sample group, wherein the target cross section is obtained by cutting each sample in the second sample group along a direction perpendicular to the rolling direction; Performing metallographic sample preparation on the target cross section to obtain a metallographic sample; A metallographic image corresponding to the metallographic sample is obtained based on a metallographic microscope, and the intergranular corrosion depth is obtained from the metallographic image.

2. The method for detecting the intergranular corrosion resistance of aluminum alloy according to claim 1, characterized in that: The obtaining the intergranular corrosion depth from the metallographic image comprises: Based on scanning electron microscopy and electron backscatter diffraction, a target area where the intergranular corrosion occurs in the metallographic image is determined, and the depth of the intergranular corrosion is measured in the target area.

3. The method for detecting the intergranular corrosion resistance of aluminum alloy according to claim 1, wherein: Obtaining the mass loss per unit area of ​​the first sample group includes: The mass loss of the samples in the first sample group is obtained, and the mass loss per unit area is obtained based on the ratio of the mass loss of the samples to the surface area of ​​the corresponding samples.

4. The method for detecting the intergranular corrosion resistance of aluminum alloy according to claim 1, wherein: The test solution is a mixed solution of sodium chloride and hydrogen chloride, wherein the concentration range of the sodium chloride is 20g / L-100g / L, and the concentration range of the hydrogen chloride is 5ml / L-20ml / L.

5. The method for detecting the intergranular corrosion resistance of aluminum alloy according to claim 1, wherein: The temperature range of the test solution is 25°C-90°C.

6. The method for detecting the intergranular corrosion resistance of aluminum alloy according to claim 1, characterized in that: The target duration ranges from 12 hours to 200 hours.

7. The method for detecting the intergranular corrosion resistance of aluminum alloy according to any one of claims 1 to 6, characterized in that: The step of obtaining the first sample group and the second sample group from the aluminum alloy plate to be tested comprises: Cutting the aluminum alloy plate to be tested to obtain a plurality of aluminum alloy blocks, and dividing the plurality of aluminum alloy blocks into two groups, respectively obtaining a first sample aluminum alloy and a second sample aluminum alloy; The exposed surfaces of the first sample aluminum alloy and the exposed surfaces of the second sample aluminum alloy are polished, and the first sample aluminum alloy is cleaned to obtain the first sample group, and the second sample aluminum alloy is cleaned to obtain the second sample group.

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