阅读说明：本技术 铝合金无织构标准样品及其制备方法 (Aluminum alloy non-texture standard sample and preparation method thereof ) 是由 董学光 王虎 田宇兴 邹立颖 李英东 吴玉龙 雷金琴 范荣辉 于 2021-10-18 设计创作，主要内容包括：本发明提供了一种铝合金无织构标准样品及其制备方法。该制备方法包括以下步骤：将原铝铝粉或牌号铝粉置于成型模具中,然后将成型模具放入等离子体成型试验机中,以对原铝铝粉或牌号铝粉进行粉末冶金等离子烧结,得到铝合金无织构标准样品；其中,对原铝铝粉进行粉末冶金等离子烧结过程中的成型温度为500～520℃,对牌号铝粉进行粉末冶金等离子烧结过程中的成型温度为520～550℃。采用本发明提供的制备方法,能够制备得到合格的铝合金无织构标准样品。该标准样品充分保持了铝粉的无序均匀状态,能够应用在铝合金织构测试的散焦校正中。(The invention provides an aluminum alloy non-texture standard sample and a preparation method thereof. The preparation method comprises the following steps: placing the original aluminum powder or the brand aluminum powder in a forming mold, and then placing the forming mold in a plasma forming tester to perform powder metallurgy plasma sintering on the original aluminum powder or the brand aluminum powder to obtain an aluminum alloy non-texture standard sample; wherein the forming temperature in the process of carrying out powder metallurgy plasma sintering on the raw aluminum powder is 500-520 ℃, and the forming temperature in the process of carrying out powder metallurgy plasma sintering on the brand aluminum powder is 520-550 ℃. By adopting the preparation method provided by the invention, the qualified aluminum alloy non-texture standard sample can be prepared. The standard sample fully keeps the disordered and uniform state of the aluminum powder, and can be applied to defocusing correction of aluminum alloy texture testing.)

1. The preparation method of the aluminum alloy non-texture standard sample is characterized by comprising the following steps of:

placing original aluminum powder or brand aluminum powder in a forming mold, and then placing the forming mold in a plasma forming testing machine to perform powder metallurgy plasma sintering on the original aluminum powder or brand aluminum powder to obtain the aluminum alloy non-texture standard sample; wherein the forming temperature of the raw aluminum powder in the powder metallurgy plasma sintering process is 500-520 ℃, and the forming temperature of the grade aluminum powder in the powder metallurgy plasma sintering process is 520-550 ℃.

2. The preparation method of claim 1, wherein the particle size of the raw aluminum-aluminum powder is less than or equal to 50 μm, and the particle size of the grade aluminum powder is less than or equal to 50 μm.

3. The preparation method according to claim 1, wherein the forming pressure in the powder metallurgy plasma sintering process is 30-80 MPa.

4. The production method according to any one of claims 1 to 3, wherein after the molding die is placed in the plasma molding tester, the temperature is raised to the molding temperature within 20 minutes; and after the temperature is raised to the forming temperature, continuing to preserve heat for 5-10 minutes to complete the powder metallurgy plasma sintering process.

5. The preparation method according to any one of claims 1 to 3, wherein the inner cavity of the forming die is a cylindrical inner cavity with a diameter of 25-35 mm.

6. The method according to claim 5, wherein the weight of the raw aluminum-aluminum powder or the grade aluminum powder placed in the forming mold is less than or equal to 40 g.

7. The method according to any one of claims 1 to 3, characterized in that after the powder metallurgy plasma sintering step is finished, the method further comprises a step of subjecting the obtained sample to a heat treatment at a treatment temperature in a range from 300 ℃ to the molding temperature; the heat treatment process has a holding temperature of at least 5 minutes.

8. The method according to any one of claims 1 to 3, wherein the material of the forming mold is steel or graphite.

9. The preparation method according to any one of claims 1 to 3, wherein the surface of the aluminum alloy non-texture standard sample to be obtained is sequentially polished by using 800-mesh, 1500-mesh and 2000-mesh sandpaper.

10. An aluminum alloy untextured standard sample prepared by the method of any one of claims 1 to 9.

Technical Field

The invention relates to the field of metal materials, in particular to an aluminum alloy non-texture standard sample and a preparation method thereof.

Background

The aluminum alloy material has the obvious advantages of high specific strength, corrosion resistance, good aesthetic effect after surface treatment and the like, and is widely applied to products such as automobile parts, mobile phones, computers and the like; due to its good electrical conductivity, is the material of choice for the anode of the battery. Most of the aluminum used in the above products is plate-shaped or foil-shaped, which requires the aluminum alloy to be subjected to a complicated rolling process. Due to the influence of the stacking fault energy, the grain size, the second phase and the like, the grains of the aluminum alloy material can be gathered in certain directions in the rolling process, and the phenomenon is called texture. The microscopic texture can often affect the macroscopic forming performance and physical performance of the material, for example, the cubic texture can cause the material to generate anisotropy, and the ear making phenomenon can occur in the production process of the pop can, which is not beneficial to the improvement of the use efficiency of the material; in the field of batteries, the cubic texture can enhance the battery capacity and is beneficial to improving the battery performance. It is important to obtain the desired texture composition by technical means. The accurate texture testing means is needed to be provided for researching the texture of the material.

At the present stage, two main ways of texture testing exist, namely an Electron Back Scattering Diffraction (EBSD) method; second, XRD method. In the XRD method, since the X-ray irradiation area varies with the variation of the test tilt angle, the data measured at different diffraction angles cannot be uniformly calculated, which requires the use of a non-textured standard sample for data defocus correction. At present, the commercialized standard sample is only produced in Poland enterprises, monopoly exists all over the world, the price is high, and the production technology is commercial confidentiality. In the domestic market, no related products of the aluminum alloy non-texture standard sample exist, and no evaluation method for the quality of the related products exists. The technical literature also introduces a preparation method of the aluminum alloy non-texture standard sample. In addition to data correction using imported expensive standard samples, the present domestic laboratory also uses the following two methods for defocus correction: 1) raw aluminum powder or aluminum alloy grade powder is purchased, and 502 glue is used for bonding the powder to be used as a non-texture standard sample for defocusing correction. The sample prepared by the method has large porosity, cannot be consistent with the porosity of the plate, and the diffraction signal is quickly attenuated under a high angle, so that the method is not in accordance with the actual situation, and the calculated texture content has large error. 2) The file generated by formula calculation is used for defocusing correction, but the method is purely a theoretical method and has larger deviation from the real situation of a test sample and an instrument, so that the calculation error is larger during data processing.

Based on the reasons, how to prepare the aluminum alloy non-texture standard sample breaks through the monopoly abroad is an urgent problem to be solved in the field of aluminum alloy texture testing.

Disclosure of Invention

The invention mainly aims to provide an aluminum alloy non-texture standard sample and a preparation method thereof, which are used for breaking the monopoly abroad and preparing the aluminum alloy non-texture standard sample, thereby reducing the defocusing correction cost in the aluminum alloy texture testing process and having good reliability.

In order to achieve the above object, according to one aspect of the present invention, there is provided a method for preparing an aluminum alloy untextured standard sample, comprising the steps of: placing the original aluminum powder or the brand aluminum powder in a forming mold, and then placing the forming mold in a plasma forming tester to perform powder metallurgy plasma sintering on the original aluminum powder or the brand aluminum powder to obtain an aluminum alloy non-texture standard sample; wherein the forming temperature in the process of carrying out powder metallurgy plasma sintering on the raw aluminum powder is 500-520 ℃, and the forming temperature in the process of carrying out powder metallurgy plasma sintering on the brand aluminum powder is 520-550 ℃.

Furthermore, the particle size of the original aluminum powder is less than or equal to 50 μm, and the particle size of the grade aluminum powder is less than or equal to 50 μm.

Furthermore, in the powder metallurgy plasma sintering process, the forming pressure is 30-80 MPa, preferably 50 MPa.

Further, after the mold to be formed is placed into a plasma forming tester, the temperature is raised to the forming temperature within 20 minutes; preferably, after the temperature is raised to the forming temperature, the temperature is kept for 5-10 minutes to complete the powder metallurgy plasma sintering process.

Further, the inner cavity of the forming die is a cylindrical inner cavity with the diameter of 25-35 mm.

Furthermore, the weight of the raw aluminum powder or the grade aluminum powder in the forming mold is less than or equal to 40g, preferably 25-30 g.

Further, after the powder metallurgy plasma sintering step is finished, the preparation method further comprises the step of carrying out heat treatment on the obtained sample, wherein the treatment temperature in the heat treatment process is within the range from 300 ℃ to the forming temperature; preferably, the incubation temperature for the heat treatment process is at least 5 minutes.

Furthermore, the material of the forming die is steel or graphite.

Further, sequentially adopting 800-mesh, 1500-mesh and 2000-mesh sandpaper to polish the surface of the aluminum alloy non-texture standard sample step by step.

According to another aspect of the invention, the aluminum alloy non-texture standard sample is prepared by the preparation method.

By adopting the preparation method provided by the invention, the qualified aluminum alloy non-texture standard sample can be prepared. The standard sample fully keeps the disordered and uniform state of the aluminum powder, and can be applied to defocusing correction of aluminum alloy texture testing. The method breaks through foreign monopoly, reduces the defocusing correction cost in the aluminum alloy texture testing process, and has good reliability.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a scanning mirror photographic representation of a virgin aluminum powder for use in examples 1 and 2 of the present invention;

FIG. 2 shows a scanning mirror photograph of a brand aluminum powder 6061 aluminum alloy powder used in examples 3 and 4 according to the present invention;

FIG. 3 shows XRD phase diagrams of untextured standard samples of aluminum alloys prepared in examples 1 and 2 of the present invention and virgin aluminum powder;

FIG. 4 shows XRD phase diagrams of aluminum alloy non-textured standard samples prepared in examples 3 and 4 of the present invention and a powder of aluminum alloy designation aluminum powder 6061;

fig. 5 shows XRD phase diagrams of aluminum alloy samples prepared by the casting methods of comparative examples 1 and 2 and virgin aluminum powder, brand aluminum powder 6061 aluminum alloy powder.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Interpretation of terms:

and (3) texturing: generally, the orientation of the polycrystal is random, but after deformation, the orientation distribution of the polycrystal deviates significantly from the random state, the number of grains in some orientation directions increases significantly, and the polycrystal shows a certain regularity, and the orientation distribution state of the polycrystal is called as texture.

Defocus correction: in the X-ray diffraction (XRD) macro texture test analysis, the intensity of the diffraction signal varies due to the tilt of the sample during the test and the change of the irradiated area of the sample according to the geometrical relationship of diffraction, and this intensity change is not caused by the texture. In order to solve the problem, the data point of the test sample is divided by the data point of the non-texture standard sample, and then the unified calculation is carried out. This process is called defocus correction.

The invention provides a preparation method of an aluminum alloy non-texture standard sample, which comprises the following steps: placing the original aluminum powder or the brand aluminum powder in a forming mold, and then placing the forming mold in a plasma forming tester to perform powder metallurgy plasma sintering on the original aluminum powder or the brand aluminum powder to obtain an aluminum alloy non-texture standard sample; wherein the forming temperature in the process of carrying out powder metallurgy plasma sintering on the raw aluminum powder is 500-520 ℃, and the forming temperature in the process of carrying out powder metallurgy plasma sintering on the brand aluminum powder is 520-550 ℃.

The aluminum alloy non-texture standard sample is prepared by adopting a powder metallurgy plasma (SPS) sintering process, the raw aluminum powder is subjected to plasma sintering molding at the temperature of 500-520 ℃, and the brand aluminum powder is subjected to plasma sintering molding at the temperature of 520-550 ℃. Compared with other methods, the aluminum powder is heated and pressed more uniformly in the powder metallurgy plasma sintering process, and the powder inside the die basically does not move relatively in the forming process. Particularly, under the temperature condition, the powder matrixes are fully sintered and bonded, so that melting is avoided and metallurgical bonding among powder particles is guaranteed. In a word, the aluminum alloy non-texture standard sample obtained by the preparation method of the invention fully maintains the disordered and uniform state of the powder matrix, and can be applied to defocusing correction of aluminum alloy texture test. The method breaks through foreign monopoly, reduces the defocusing correction cost in the aluminum alloy texture testing process, and has good reliability.

The raw aluminum powder or the aluminum powder of the grade can be obtained by commercial purchase. The purity of the raw aluminum powder, namely the aluminum powder directly prepared from the aluminum prepared in the ore smelting process, is usually over 99.7 percent. The grade aluminum powder is aluminum alloy powder formed by doping other trace elements in the original aluminum powder, and the grade aluminum powder can be 6061 grade aluminum powder.

When the raw aluminum powder is subjected to powder metallurgy plasma sintering, the forming temperature is 500-520 ℃; when powder metallurgy plasma sintering is carried out on the aluminum powder, the forming temperature is 520-550 ℃. The forming temperature is selected according to different aluminum powder, so that the sintering effect is better for the corresponding aluminum powder, and the particles of the non-texture sample are more uniform.

In a preferred embodiment, the particle size of the aluminum powder is less than or equal to 50 μm, and the particle size of the brand aluminum powder is less than or equal to 50 μm. The particle size of the aluminum powder is controlled within the range, which is more beneficial to metallurgical bonding of the grain boundary. More preferably, the maximum particle size of the raw aluminum-aluminum powder and the grade aluminum powder is 30 to 50 μm.

In order to form better metallurgical bonding between aluminum powder and avoid the problems of too high equipment requirement or too high energy consumption caused by too high pressure, in a preferred embodiment, the forming pressure is 30-80 MPa, and preferably 50 MPa. The plasma sintering is carried out under the forming pressure, the aluminum powder particles are combined more tightly, the formed sample can fully keep the uniform and unnecessary state of the aluminum powder, and the non-texture quality is better.

In a preferred embodiment, the temperature is raised to the molding temperature within 20 minutes after the mold to be molded is placed in the plasma molding tester. On one hand, the forming efficiency can be improved, on the other hand, the aluminum powder can be heated more uniformly, and the formation of a non-texture state is favorably influenced. For example, the temperature may be raised to the molding temperature within 5 to 20 minutes, preferably within 10 to 20 minutes. Preferably, after the temperature is raised to the forming temperature, the temperature is kept for 5-10 minutes to complete the powder metallurgy plasma sintering process. Under the long-term condition of this heat preservation, the metallurgical bonding between the aluminium powder granule is inseparabler, and the aluminium alloy sample that obtains has had good mechanical strength concurrently, is favorable to the used repeatedly in the defocus calibration process.

In the actual forming process, the selected mold has only to have higher strength and can bear the high temperature, and the forming mold is made of steel or graphite, for example. Preferably, the inner cavity of the forming die is a cylindrical inner cavity with the diameter of 25-35 mm. The aperture is too small, which is not beneficial to the use of a standard sample, and the uniformity of the heated and pressed aluminum powder is inevitably reduced if the aperture is too large. Therefore, the invention preferably controls the size of the inner cavity of the forming die within the range, which is beneficial to the use of the standard sample, can also better improve the heated and pressed uniformity of the powder, and is more beneficial to improving the non-texture property of the sample.

In a preferred embodiment, the weight of the aluminum powder placed in the forming mold is 40g or less. Similarly, too much aluminum powder is not favorable for uniformity of the surface and the core after molding, and the weight is preferably controlled within the above range, and more preferably, the weight of the aluminum powder placed in the molding die is 25 to 30 g.

And after plasma sintering and forming, releasing pressure, opening the die, and cooling the sample to obtain the standard sample. More preferably, after the powder metallurgy plasma sintering step is finished, the preparation method further comprises the step of carrying out heat treatment on the obtained sample, wherein the treatment temperature of the heat treatment process is in the range of 300 ℃ to the forming temperature. The residual stress in the sample can be relieved by the heat treatment described above. Further preferably, the incubation temperature for the heat treatment process is at least 5 minutes. The heat treatment process can be performed after the mold is opened and the mold is cooled.

Preferably, the surface of the aluminum alloy non-texture standard sample to be obtained is polished step by using 800-2000-mesh sand paper. For example, the sample can be polished by sequentially using 800-mesh, 1500-mesh or 2000-mesh sandpaper step by step until the surface of the sample is smooth.

According to another aspect of the invention, the aluminum alloy non-texture standard sample is prepared by the preparation method. The aluminum alloy non-texture standard sample prepared by the method fully maintains the disordered and uniform state of the aluminum powder, and has good non-texture quality and low preparation cost.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

Example 1

Raw materials: the purity of the commercialized raw aluminum-aluminum powder is more than 97%, the particle size is less than or equal to 50 microns, and a scanning electron micrograph is shown in figure 1.

Selecting a steel mould as a forming mould, putting a lower mould into an inner hole of a main body of the steel mould, and placing the lower mould on a table top; wherein the inner hole of the die is a cylindrical hole with the diameter of 30 mm.

29g of aluminum powder is weighed and poured into the main body hole of the mold, and the upper mold is placed in the main body hole of the mold.

Placing the die in a plasma forming tester, heating to 500 ℃ within 10 minutes, adjusting the forming pressure to 50MPa, and then preserving heat for 5 minutes to perform powder metallurgy plasma sintering;

and after the forming is finished, releasing pressure, taking out the sample, cooling, heating to 500 ℃ for heat treatment for 5 minutes, and finally, sequentially polishing the surface of the sample by using 800-mesh, 1500-mesh and 2000-mesh abrasive paper step by step until the surface is smooth to obtain the aluminum alloy non-texture standard sample, wherein the sample is marked as sample No. 1.

Example 2

The difference from the embodiment 1 is that: the molding temperature was 520 ℃ and the heat treatment temperature was 520 ℃. The prepared aluminum alloy non-texture standard sample is marked as sample No. 2.

Example 3

Raw materials: 6061 aluminum powder with particle size less than or equal to 50 μm, and the scanning electron micrograph is shown in FIG. 2.

Selecting a steel mould as a forming mould, putting a lower mould into an inner hole of a main body of the steel mould, and placing the lower mould on a table top; wherein the inner hole of the die is a cylindrical hole with the diameter of 30 mm.

29g of aluminum powder is weighed and poured into the main body hole of the mold, and the upper mold is placed in the main body hole of the mold.

Placing the die in a plasma forming tester, heating to 520 ℃ within 10 minutes, adjusting the forming pressure to 50MPa, and then preserving heat for 5 minutes to perform powder metallurgy plasma sintering;

and after the forming is finished, releasing pressure, taking out the sample, cooling, heating to 520 ℃ for heat treatment for 5 minutes, and finally, sequentially polishing the surface of the sample by using 800-mesh, 1500-mesh and 2000-mesh abrasive paper step by step until the surface is smooth to obtain the aluminum alloy non-texture standard sample, wherein the sample is marked as No. 3 sample.

Comparative example 1

The difference from the embodiment 1 is that: and preparing an aluminum alloy sample by adopting a casting method, wherein the casting temperature is 680 ℃, and the sample is marked as A.

Comparative example 2

The difference from the embodiment 3 is that: and preparing an aluminum alloy sample by adopting a fusion casting method, wherein the fusion casting temperature is 700 ℃, and recording as a sample B.

XRD tests were performed on the aluminum alloy non-textured standard samples in the above examples and comparative examples, and compared with virgin aluminum powder and 6061 aluminum powder. The results are shown in the figures, wherein fig. 3 shows XRD phase diagrams of aluminum alloy non-textured standard samples (sample nos. 1 and 2) prepared in examples 1 and 2 of the present invention and raw aluminum powder; FIG. 4 shows XRD phase diagrams of aluminum alloy untextured standard samples (sample Nos. 3 and 4) and aluminum alloy powder designation aluminum powder 6061 prepared in examples 3 and 4 of the present invention; fig. 5 shows XRD physical phase diagrams of aluminum alloy samples (sample a and sample B) prepared by the fusion casting method of comparative examples 1 and 2, and virgin aluminum-powder and aluminum-powder 6061 aluminum alloy powder.

As can be seen from FIGS. 3 and 4, the diffraction peak intensity distribution rule of the aluminum alloy non-texture standard sample prepared by the embodiment of the invention is basically consistent with that of the original aluminum powder and 6061 aluminum powder, which shows that the standard sample prepared by the invention has higher quality.

In addition, when the sample generates the texture, the proportion of the three-strong-peak diffraction intensity of the sample can be obviously changed, and the sample has stronger sensitivity to whether the texture exists in the sample, so the invention also adopts the following indexes as evaluation indexes for judging the quality of the standard sample. Calculating the deviation degree of the diffraction intensity ratio of the three intensity peaks: the three strong peaks of the XRD phase of the aluminum alloy powder material are tested, the intensity percentages of the three peaks are calculated to be used as a standard, and the XRD test is carried out on the standard sample prepared by the technical scheme and the process provided by the invention, and the percentage of the three strong peaks is calculated. Substituting the following formula for calculation:

wherein I (bias) is the deviation degree of diffraction intensity ratio of three strong peaks, X_{Standard sample (HKL)}Is the relative intensity percentage of the (HKL) diffraction peak, S_powder(HKL)Is the strength percentage of three peaks of the powder material, and the quality of the prepared standard sample is higher than that of the traditional solution method through the research that the value of I (bias) is less than or equal to 0.4.

To accurately determine the quality of the standard sample, the samples in the examples and comparative examples were subjected to i (bias) calculation using the above criteria, and the results were as follows:

from the above data, it can be seen that the values of i (bias) of the aluminum alloy samples prepared by the above embodiments of the present invention are all less than or equal to 0.4, which indicates that the aluminum alloy samples have better non-texture characteristics and better quality, and are more suitable for being used as standard samples for defocusing correction in the aluminum alloy XRD test process.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.