A cobalt-containing as-cast aluminum alloy material and a preparation method and application thereof

Abstract

The application discloses a kind of cobalt-containing cast aluminum alloy materials and its preparation method and application.The method steps of the present application include: by Al, Cu is melted to obtain metal liquid 1, add first intermediate alloy, melt, add second intermediate alloy, melt, add third intermediate alloy, melt, add pure Zn, melt, temperature is raised to 835 DEG C, add composite salt, heat preservation, vibration, the obtained metal liquid is poured into the casting mold under vibration, and the temperature reaches about 200 DEG C, stop heating to the casting mold after pouring, and the casting mold is cooled to less than 350 DEG C at room temperature, stop vibration, and the casting mold continues to cool to cold 200 DEG C after opening mold, to obtain cobalt-containing cast aluminum alloy material.The present application improves the internal quality of cast alloy, and the mechanical comprehensive performance of material ductility, tensile strength and the like is better.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy material processing, specifically to a cobalt-containing cast aluminum alloy material, its preparation method, and its application. Background Technology

[0002] Aluminum alloys possess advantages such as low density, high specific strength, and good corrosion resistance, playing a vital role in industrial applications. Introducing different alloying elements into pure aluminum creates aluminum alloys with varying performance characteristics to meet the needs of diverse applications.

[0003] Al-Co binary alloys possess high hardness, good high-temperature strength, and corrosion resistance, making them widely used in heat-resistant / wear-resistant structural components. As shown in the Al-Co binary phase diagram, cobalt has extremely low equilibrium solubility in aluminum (<0.1%). At 665℃ and a Co content of 0.68%, a eutectic reaction occurs between L and Al, resulting in the acicular Al9Co2 phase. Al-Co binary alloys are also used as grain refiners in aluminum alloys, refining α-Al grains and providing grain-refining strengthening. Currently, Al-Si alloys are commonly used in the production of 5G communication equipment housings and new energy battery brackets, but these alloys suffer from insufficient overall mechanical properties.

[0004] As-cast aluminum alloys often exhibit poor mechanical properties due to their coarse dendritic primary structure. Commonly used techniques include alloying or adding grain refiners to refine the primary grain structure. Further physical methods, such as mechanical stirring, can further refine the grains. However, for acicular or lamellar second-phase structures, adding grain refiners or auxiliary stirring has little effect on refining the grains.

[0005] Therefore, it is necessary to develop new types of aluminum alloys to meet the growing demand for high-plasticity cast aluminum alloy materials. Summary of the Invention

[0006] To overcome the shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a cobalt-containing cast aluminum alloy material, its preparation method, and its application.

[0007] The technical solution provided by this invention is as follows:

[0008] A method for preparing a cobalt-containing cast aluminum alloy material, the method comprising the following steps:

[0009] (1) Take pure Al, cover it with rice husk carbon, heat it to 770℃, keep it at 15~20min until the pure Al partially melts, then add pure Cu, heat it to 800℃, keep it at 15~20min until the pure Cu and Al are completely melted, then remove the slag to obtain liquid metal 1.

[0010] (2) Mechanically stir the molten metal 1 and add the first intermediate alloy. After the first intermediate alloy has completely melted, remove the slag to obtain molten metal 2.

[0011] (3) Mechanically stir the molten metal 2 and add the second intermediate alloy. After the second intermediate alloy has completely melted, remove the slag to obtain molten metal 3.

[0012] (4) Mechanically stir the molten metal 3 and add the third intermediate alloy. After the third intermediate alloy is completely melted, add pure Zn until it is completely fused. Remove the slag to obtain molten metal 4.

[0013] (5) Mechanically stir the molten metal 4, heat it to 835℃, add composite salt, keep it at the temperature for 5~8 minutes, and vibrate it. Remove the slag during the vibration process to obtain molten metal 5.

[0014] (6) The mold is preheated by induction heating at a frequency of 20~30kHz. When the mold temperature reaches about 200℃, the frequency is adjusted to the range of 10~15Hz. The molten metal 5 is poured into the mold under vibration. After pouring, the induction heating of the mold is stopped 1 minute later. The vibration is stopped when the mold is cooled to less than 350℃ at room temperature. The mold is then opened after cooling to 200℃ to obtain cobalt-containing cast aluminum alloy material.

[0015] Preferably, in step (2), the first intermediate alloy is Al-10Co.

[0016] Preferably, in step (3), the second intermediate alloy is at least one of Al-10Li, Al-10Nb, Al-5Zr and Al-10V.

[0017] Preferably, in step (4), the third intermediate alloy is Al-10Sr and AlTi5B1.

[0018] Preferably, in step (5), the composite salt is composed of NaCl, KCl, and NaF in a mass ratio of 1:1:1.

[0019] Preferably, in step (5), the frequency of the vibration is 10~15Hz and the amplitude is 1.5~2mm.

[0020] Preferably, the cobalt-containing cast aluminum alloy material contains the following components by weight percentage: 0.5-2.0% cobalt, 1.5-3.0% copper, 1-7% zinc, 0.5-1.0% strontium, 0-0.25% zirconium, 0-0.25% vanadium, 0-0.25% lithium, 0-0.25% niobium, 0.05-0.25% titanium, 0.01-0.05% boron, with the balance being aluminum.

[0021] The present invention further discloses the cobalt-containing cast aluminum alloy material prepared by the above method.

[0022] This invention further discloses the application of the above-mentioned cobalt-containing cast aluminum alloy material in the preparation of 5G communication equipment housings and new energy battery brackets.

[0023] The beneficial effects of this invention after adopting the above technical solution are as follows:

[0024] (1) The present invention uses alloying elements (Cu, Zn) with high solid solubility in pure aluminum to strengthen the matrix phase α-Al through solid solution. The introduction of Co element forms Al9Co2 second phase with Al, which has a grain-refining effect on the matrix phase α-Al and can achieve grain-refining strengthening effect. In addition, during the tensile deformation process, it hinders dislocation movement and improves the tensile strength of aluminum alloy. At the same time, the small size of the second phase reduces local stress concentration and slows down the tendency of crack initiation and propagation, thereby improving the ductility of the alloy.

[0025] (2) In the casting process of this invention, the induction effect is used to regulate the solidification dynamics of the alloy. The electromagnetic vibration and stirring effect are used to interfere with the solute distribution at the solid-liquid interface and the fluid shear force inhibits the directional growth of grains. In addition, the effect of induction heating of the mold is used to delay the solidification trend of the molten metal in the mold, reduce the slag inclusion casting defects caused by the molten metal solidifying too quickly and not having enough time to float to the surface, and improve the internal quality of the cast alloy.

[0026] (3) In the casting process of this invention, by changing the induction frequency, the sample obtained after induction heating and electromagnetic stirring is transformed from the original needle-like second-phase structure into a short rod-like structure, and the elongation is significantly increased to 2.5 times that of the sample prepared without this device. The strength is reduced by 18%, which effectively solves the contradiction between the strength and plasticity of aluminum alloys, so that the aluminum alloy has both high plasticity and high strength. Due to the good comprehensive mechanical properties of this alloy, it is expected to be a candidate material for large-size castings such as battery brackets or car bodies in the integrated die casting of new energy vehicles. Attached Figure Description

[0027] Figure 1 This is a metallographic image of the microstructure of the cobalt-containing cast aluminum alloy material 1 prepared in Example 1 of the present invention.

[0028] Figure 2 This is a metallographic image of the microstructure of the cast aluminum alloy material 6 prepared in Comparative Example 1 of this invention.

[0029] Figure 3 A schematic diagram of the structure of the induction vibration casting table in this invention; wherein, 1-cast mold; 2-induction heater; 3-vibration table. Detailed Implementation

[0030] The technical solution of the present invention will be further described in detail below with reference to specific embodiments, but this does not constitute any limitation on the present invention.

[0031] Materials used in this invention and their sources: All materials used in this invention are commercially available products, wherein: the purity of pure Zn is greater than or equal to 99.9 wt.%, the purity of pure Al is greater than or equal to 99.9 wt.%, and the purity of pure Cu is greater than or equal to 99.9 wt.%; the blocky Al-10Co master alloy, rod-shaped Al-10Sr master alloy, blocky Al-10Li master alloy, rod-shaped AlTi5B1 master alloy, blocky Al-5Zr master alloy, and blocky Al-10V master alloy are all pre-made products. The Al-10Sr contains 90 wt.% Al and 10 wt.% Sr, the Al-10Co contains 90 wt.% Al and 10 wt.% Co, the Al-10Li contains 90 wt.% Al alloy and 10 wt.% Li, the Al-5Zr contains 95 wt.% Al and 5 wt.% Zr, and the Al-10V contains 90 wt.% Al and 10 wt.% V.

[0032] The inductive vibration casting platform involved in the embodiments of the present invention, such as Figure 3 As shown, it includes a vibration table 3 at the bottom, an induction heater 2 located on the vibration table 3, and a mold 1 located on the induction heater 2.

[0033] Example 1

[0034] (1) Take pure Al, cover it with rice husk carbon, heat it to 770℃, keep it at the temperature for 15~20min, after the pure Al partially melts, add pure Cu, heat it to 800℃, and keep it at the temperature for 15~20min; after the pure Cu and Al are completely melted, remove the slag to obtain liquid metal 1.

[0035] (2) Mechanically stir the molten metal 1 and add the first intermediate alloy Al-10Co. After the first intermediate alloy Al-10Co has completely melted, remove the slag to obtain molten metal 2.

[0036] (3) Mechanically stir the molten metal 2 and add the second intermediate alloy Al-10Li. After the second intermediate alloy Al-10Li has completely melted, remove the slag to obtain molten metal 3.

[0037] (4) Mechanically stir the molten metal 3 and add the third intermediate alloy (Al-10Sr and AlTi5B1). After the third intermediate alloy (Al-10Sr and AlTi5B1) has completely melted, add pure Zn until it is completely fused, remove the slag, and obtain the molten metal 4.

[0038] (5) Mechanically stir the molten metal 4, heat it to 835℃, add composite salt (NaCl:KCl:NaF=1:1:1), keep it at the temperature for 5~8min, and then vibrate it (vibration frequency is 10~15Hz, amplitude is 1.5~2mm). During the vibration process, remove the residual slag on the surface of the molten metal to obtain molten metal 5.

[0039] (6) Turn on the induction heater (output power of 3000W) placed on the vibration table to preheat the mold with induction heating at a frequency of 20~30kHz (amplitude of 2.5~3mm). When the mold temperature reaches about 200℃, adjust the frequency to 10~15Hz (amplitude of 2.5~3mm). Pour the molten metal 5 into the mold under vibration. Stop the induction heating of the mold 1 minute after pouring. Stop the vibration when the mold cools to less than 350℃ at room temperature. After the mold continues to cool to 200℃, open the mold to obtain cobalt-containing cast aluminum alloy material 1.

[0040] In this embodiment, the high-plasticity cast aluminum alloy contains the following components by weight percentage: 1% cobalt, 1.5% copper, 0.25% strontium, 0.1% vanadium, 0.15% lithium, 0.05% titanium, 0.005% boron, with the balance being aluminum.

[0041] Example 2

[0042] Example 2 is basically the same as Example 1, except that in Example 2, the amount of each component added in the cobalt-containing cast aluminum alloy material 2 by weight percentage is: 1.3% cobalt, 1.85% copper, 4.5% zinc, 0.25% strontium, 0.15% zirconium, 0.2% lithium, 0.0025% titanium, 0.0005% boron, and the balance is aluminum.

[0043] Example 3

[0044] Example 3 is basically the same as Example 1, except that in Example 3, the amount of each component added in the cobalt-containing cast aluminum alloy material 3 by weight percentage is: 1% cobalt, 2% copper, 0.25% strontium, 0.15% niobium, 0.25% lithium, 0.0025% titanium, 0.0005% boron, and the balance is aluminum.

[0045] Example 4

[0046] Example 4 is basically the same as Example 1, except that in step (3), the second intermediate alloy is Al-10Nb.

[0047] In this Example 4, the cobalt-containing cast aluminum alloy material 4 obtained contains the following components by weight percentage: 1% cobalt, 2% copper, 0.25% strontium, 0.15% niobium, 0.25% niobium, 0.0025% titanium, 0.0005% boron, with the balance being aluminum.

[0048] Example 5

[0049] Example 4 is basically the same as Example 1, except that in step (3), the second intermediate alloy is Al-10V.

[0050] In this Example 4, the cobalt-containing cast aluminum alloy material 5 obtained has the following weight percentages of each component: 1% cobalt, 2% copper, 0.25% strontium, 0.15% niobium, 0.25% vanadium, 0.0025% titanium, 0.0005% boron, and the balance being aluminum.

[0051] Comparative Example 1

[0052] Comparative Example 1 is basically the same as Example 1, except that the electromagnetic induction device is not turned on during the pouring process in step (6), specifically:

[0053] (6) Turn on the vibration table, pour the molten metal that has been treated by removing slag into the mold, turn off the vibration table after the infrared thermometer detects that the temperature of the mold is less than 350°C, and continue to cool it to 200°C before opening the mold to obtain the cobalt-containing cast aluminum alloy material 6.

[0054] In the cobalt-containing cast aluminum alloy material 6 obtained in Comparative Example 1, the weight percentages of each component are as follows: 1% cobalt, 1.5% copper, 0.25% strontium, 0.1% vanadium, 0.15% lithium, 0.05% titanium, 0.005% boron, and the balance is aluminum.

[0055] Comparative Example 2

[0056] Comparative Example 2 is basically the same as Example 1, except that the amount of the first intermediate alloy added in step (2) is increased to increase the cobalt content.

[0057] In the cobalt-containing cast aluminum alloy material 7 obtained in Comparative Example 2, the weight percentages of each component are as follows: 2% cobalt, 1.5% copper, 0.25% strontium, 0.1% vanadium, 0.15% lithium, 0.05% titanium, 0.005% boron, and the balance is aluminum.

[0058] Comparative Example 3

[0059] Comparative Example 3 is basically the same as Example 1, except that the amount of the first intermediate alloy added in step (2) is reduced to reduce the cobalt content.

[0060] In the cobalt-containing cast aluminum alloy material 8 obtained in Comparative Example 3, the weight percentages of each component are as follows: 0.5% cobalt, 1.5% copper, 0.25% strontium, 0.1% vanadium, 0.15% lithium, 0.05% titanium, 0.005% boron, and the balance is aluminum.

[0061] Effect Example

[0062] The cobalt-containing cast aluminum alloy materials 1-3 prepared in Examples 1-3 and the cobalt-containing cast aluminum alloy materials 6-8 prepared in Comparative Examples 1-3 were subjected to performance tests. The test methods were in accordance with GB / T 228.1-2010 "Metallic materials - Tensile testing - Part 1: Room temperature test method". The results are shown in Table 1 below.

[0063] Table 1. Statistical Comparison of Experimental Results

[0064]

[0065] As shown in Table 1, the cobalt-containing cast aluminum alloy materials 1-3 of Examples 1-3 exhibit superior overall performance compared to the cobalt-containing cast aluminum alloy materials 6-8 of Comparative Examples 1-3. In Examples 1 and Comparative Example 1, from... Figure 1 and Figure 2 As can be seen from the metallographic image, the morphology of the Al9Co2 phase in the aluminum alloy was altered by applying an induced magnetic field during solidification, changing it from needle-like to blocky. An appropriate amount of cobalt addition resulted in better overall mechanical properties of the aluminum alloy; excessively high or low cobalt additions led to either low tensile strength or insufficient elongation. Adding an appropriate amount of zinc, which dissolves into the aluminum alloy matrix, provides solid solution strengthening, which is beneficial for improving the overall performance of the aluminum alloy.

[0066] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a cobalt-containing cast aluminum alloy material, characterized in that, The method includes the following steps: (1) Take pure Al, cover it with rice husk carbon, heat it to 770℃, keep it at 15~20min until the pure Al partially melts, then add pure Cu, heat it to 800℃, keep it at 15~20min until the pure Cu and Al are completely melted, then remove the slag to obtain liquid metal 1. (2) Mechanically stir the molten metal 1 and add the first intermediate alloy. After the first intermediate alloy has completely melted, remove the slag to obtain molten metal 2. (3) Mechanically stir the molten metal 2 and add the second intermediate alloy. After the second intermediate alloy has completely melted, remove the slag to obtain molten metal 3. (4) Mechanically stir the molten metal 3 and add the third intermediate alloy. After the third intermediate alloy is completely melted, add pure Zn until it is completely fused. Remove the slag to obtain molten metal 4. (5) Mechanically stir the molten metal 4, heat it to 835℃, add composite salt, keep it at the temperature for 5~8 minutes, and vibrate it. Remove the slag during the vibration process to obtain molten metal 5. (6) The mold is preheated by induction heating at a frequency of 20~30kHz. When the mold temperature reaches about 200℃, the frequency is adjusted to the range of 10~15Hz. The molten metal 5 is poured into the mold under vibration. After pouring, the induction heating of the mold is stopped 1 minute later. The vibration is stopped when the mold is cooled to less than 350℃ at room temperature. The mold is then opened after cooling to 200℃ to obtain cobalt-containing cast aluminum alloy material.

2. The method as described in claim 1, characterized in that, In step (2), the first intermediate alloy is Al-10Co.

3. The method as described in claim 1, characterized in that, In step (3), the second intermediate alloy is at least one of Al-10Li, Al-10Nb, Al-5Zr and Al-10V.

4. The method as described in claim 1, characterized in that, In step (4), the third intermediate alloy is Al-10Sr and AlTi5B1.

5. The method as described in claim 1, characterized in that, In step (5), the composite salt is composed of NaCl, KCl and NaF in a mass ratio of 1:1:

1.

6. The method as described in claim 1, characterized in that, In step (5), the frequency of the vibration is 10~15Hz and the amplitude is 1.5~2mm.

7. The method as described in claim 1, characterized in that, The cobalt-containing cast aluminum alloy material contains the following components by weight percentage: 0.5-2.0% cobalt, 1.5-3.0% copper, 1-7% zinc, 0.5-1.0% strontium, 0-0.25% zirconium, 0-0.25% vanadium, 0-0.25% lithium, 0-0.25% niobium, 0.05-0.25% titanium, 0.01-0.05% boron, with the balance being aluminum.

8. The cobalt-containing cast aluminum alloy material prepared by the method according to any one of claims 1 to 7.

9. The application of the cobalt-containing cast aluminum alloy material as described in claim 8 in the preparation of 5G communication equipment housings and new energy battery brackets.

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