ALUMINUM ALLOY AND PREPARATION METHOD THEREOF

Info

Publication number: 20230002864
Type: Application
Filed: Mar 26, 2020
Publication Date: Jan 5, 2023
Inventors: Qiang GUO (Shenzhen), Mengde WANG (Shenzhen), Wei AN (Shenzhen)
Application Number: 17/780,493

Abstract

An aluminum alloy and a preparation method thereof are provided. In percentage by mass, the aluminum alloy includes: 8-11% of Si, 2-3% of Cu, 0.7-1.1% of Mg, 0.7-1.5% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.02-0.1% of Ti, 0.01-0.02% of Ga, 0.004-0.02% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

Description

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure is the U.S. National Stage Application of PCT International Application No. PCT/CN2020/081455, filed on Mar. 26, 2020, which claims priority to and benefits of Chinese Patent Application No. 201911174477.0 filed on Nov. 26, 2019, which are incorporated herein by reference in their entireties.

FIELD

The present disclosure relates to the technical field of die-casting aluminum alloy, and more specifically, to an aluminum alloy and a preparation method thereof.

BACKGROUND

Die casting is a precision casting process that is characterized by forcing molten metal under high pressure into a metal mold cavity with a complex shape. Die castings are characterized by a very small dimensional tolerance and a high surface precision. In most cases, die castings can be directly assembled for use without turning.

Die casting of aluminum alloys has high requirements on their mechanical properties, such as yield strength, tensile strength, elongation, and melt fluidity. During die casting, existing die-casting aluminum alloy materials are highly dependent on the accuracy of control conditions for the formation process and are greatly affected by slight variation in process parameters, so that it is difficult to give consideration to the requirements of both the strength and elongation for die casting.

SUMMARY

To resolve the problem that it is difficult to give consideration to process requirements for existing die-casting aluminum alloy materials, the present disclosure discloses an aluminum alloy and a preparation method.

The technical solutions adopted by the present disclosure to resolve the foregoing technical problem are as follows:

According to an aspect, the present disclosure provides an aluminum alloy. In percentage by mass, the aluminum alloy includes: 8-11% of Si, 2-3% of Cu, 0.7-1.1% of Mg, 0.7-1.5% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.02-0.1% of Ti, 0.01-0.02% of Ga, 0.004-0.02% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

In some embodiments, in percentage by mass, the aluminum alloy includes: 9-10.8% of Si, 2.5-2.8% of Cu, 0.7-1.1% of Mg, 0.9-1.3% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.03-0.1% of Ti, 0.01-0.015% of Ga, 0.004-0.01% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

According to the aluminum alloy in some embodiments of the present disclosure, the mass ratio of Ti to B is (5-10):1.

According to the aluminum alloy in some embodiments of the present disclosure, the content of Ga in percentage by mass is greater than the content of Sr in percentage by mass.

According to the aluminum alloy in some embodiments of the present disclosure, the content of Si and the content of Cu satisfy the following condition: Wt(Si)=(Wt(Cu)−0.2)×(3−5).

According to the aluminum alloy in some embodiments of the present disclosure, the content of Mn and the content of Cu satisfy the following condition: Wt(Cu)=(Wt(Mn)−0.3)×(2.5−4).

According to the aluminum alloy in some embodiments of the present disclosure, the other elements include one or more of Zr, Ni, Ce, Sc, and Er.

According to another aspect, the present disclosure provides a method for preparing the foregoing aluminum alloy. The method includes the following steps: weighing out various raw materials in required proportions based on proportions of all elements in the aluminum alloy, melting the raw materials in a melting furnace to obtain a molten metal, and subjecting the molten metal to slag removal and refining and degassing, and then casting, to obtain an aluminum alloy ingot.

According to the method in some embodiments of the present disclosure, the slag removal includes adding a slag remover into the molten metal, the slag remover including one or more of an aluminum alloy slag remover agent NF-1 and an aluminum alloy slag-removal agent DSG.

According to the method in some embodiments of the present disclosure, the refining is carried out at 700-710° C., and the refining includes adding a refining agent into the molten metal, the refining agent including one or more of hexafluoroethane and an aluminum refining agent ZS-AJ01C.

According to the method in some embodiments of the present disclosure, the method further includes die casting the aluminum alloy ingot for formation.

According to the method in some embodiments of the present disclosure, the method includes carrying out artificial aging on the die-cast aluminum alloy.

According to the method in some embodiments of the present disclosure, the artificial aging is carried out at 100-200° C. for 1.5-3 h.

By adjusting proportions of all strengthening elements in the aluminum alloy, the aluminum alloy provided in the present disclosure has high yield strength and thermal conductivity, and ensures good elongation without sacrificing the strength. For the aluminum alloy in the present disclosure, the yield strength is about 240-260 MPa, the tensile strength is about 380-410 MPa, the elongation is 3-6%, and the thermal conductivity is about 130-142 W/(k·m). In addition, the aluminum alloy material has low process requirements, and has good process adaptability in die casting.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a metallographic image of an aluminum alloy prepared in Example 1 of the present disclosure;

FIG. 2 is an SEM image of an aluminum alloy prepared in Example 1 of the present disclosure; and

FIG. 3 is an SEM-diffraction spectrum of the area marked with the cross in FIG. 2.

DETAILED DESCRIPTION

To make the technical problems to be resolved by the present disclosure, technical solutions, and beneficial effects more comprehensible, the following further describes the present disclosure in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely used for explaining the present disclosure instead of limiting the present disclosure.

According to an aspect, the present disclosure provides an aluminum alloy. In percentage by mass, the aluminum alloy includes: 8-11% of Si, 2-3% of Cu, 0.7-1.1% of Mg, 0.7-1.5% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.02-0.1% of Ti, 0.01-0.02% of Ga, 0.004-0.02% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

By adjusting proportions of all strengthening elements in the aluminum alloy, the aluminum alloy provided in the present disclosure has high yield strength and thermal conductivity, and ensures good elongation without sacrificing the strength. For the aluminum alloy in the present disclosure, the yield strength is about 240-260 MPa (for example, 240 MPa, 242 MPa, 245 MPa, 248 MPa, 250 MPa, 251 MPa, 253 MPa, 255 MPa, 258 MPa, or 260 MPa), the tensile strength is about 380-410 MPa (for example, 380 MPa, 385 MPa, 390 MPa, 395 MPa, 400 MPa, 405 MPa, or 410 MPa), the elongation is about 3-6% (for example, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, or 6%), and the thermal conductivity is about 130-142 W/(k·m) (for example, 130 W/(k·m), 132 W/(k·m), 135 W/(k·m), 138 W/(k·m), 140 W/(k·m), or 142 W/(k·m)). In addition, the aluminum alloy material has low process requirements, and has good process adaptability in die casting.

In some embodiments, in percentage by mass, the aluminum alloy includes: 9-10.8% of Si, 2.5-2.8% of Cu, 0.7-1.1% of Mg, 0.9-1.3% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.03-0.1% of Ti, 0.01-0.015% of Ga, 0.004-0.01% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

In some other embodiments, the aluminum alloy is composed of the following components in percentage by mass: 9-10.8% of Si, 2.5-2.8% of Cu, 0.7-1.1% of Mg, 0.9-1.3% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.03-0.1% of Ti, 0.01-0.015% of Ga, 0.004-0.01% of B, 0-2% of Zn, and the balance of Al.

In some embodiments, the content of Si is 9%, 9.8%, 10%, 10.5%, or 10.8%, the content of Cu is 2.5%, 2.6%, or 2.8%, the content of Mg is 0.7%, 0.8%, 0.9%, 1%, or 1.1%, the content of Mn is 0.9%, 1%, 1.1%, 1.2%, or 1.3%, the content of Sr is 0.01%, 0.013%, 0.015%, or 0.02%, the content of Cr is 0.01%, 0.013%, or 0.015%, the content of Fe is 0, 0.1%, 0.2%, 0.3%, or 0.4%, the content of Ti is 0.03%, 0.04%, 0.05%, or 0.06%, the content of Ga is 0.01%, 0.013%, or 0.015%, the content of B is 0.004%, 0.005%, 0.006%, 0.007%, or 0.008%, and the content of Zn is 0, 0.3%, 0.6%, 0.9%, 1.3%, 1.7%, or 2%.

In the materials involved in the present disclosure, Si and Al form eutectic Si and primary Si. Dispersed primary Si and fine α-Al grains are formed under the effect of Sr, increasing the strength and fluidity of the aluminum alloy.

According to the aluminum alloy in some embodiments of the present disclosure, Cu is solubilized into Al to form a solid solution phase, and precipitated Al₂Cu strengthening phase is dispersed on the grain boundary.

According to the aluminum alloy in some embodiments of the present disclosure, with the increase of Mg content, the yield strength increases and the elongation decreases gradually. When the Mg content is more than 0.7%, a dispersion strengthening phase (with a particle size below 10 μm) mainly composed of Al₂Cu is precipitated. With the increase of the Mg content, the area occupied by this phase in the aluminum alloy gradually increases. When the Mg content is more than 1.1%, the grains of this phase in the aluminum alloy will increase sharply, and the elongation will decrease greatly.

According to the aluminum alloy in some embodiments of the present disclosure, Mn and Cr are solubilized into the aluminum alloy matrix to inhibit the grain growth of primary Si and α-Al, so that the primary Si is dispersed among grains.

According to the aluminum alloy in some embodiments of the present disclosure, Ti and B are dispersed among the grains, so that primary Si can uniformly distribute into α-Al, which greatly inhibits the growth of α-Al (the particle size of α-Al is reduced by one-third compared with that in the aluminum alloy without the addition of Ti and B).

According to the aluminum alloy in some embodiments of the present disclosure, an excessively high content of Zn is easily solubilized into the aluminum alloy, thereby affecting the solubilization of Cu, Mn, and Mg, which will affect the precipitated second phase and greatly change the thermal conductivity of the aluminum alloy.

According to the aluminum alloy in some embodiments of the present disclosure, an excessively high content of Fe will make the aluminum alloy brittle and thus affect the elongation of the aluminum alloy.

The mechanical properties, thermal conductivity, and elongation of the aluminum alloy are the result of the combined effect of the foregoing elements. Any element that deviates from the scope provided by the present disclosure deviates from the disclosure intent of the present disclosure, resulting in a reduction in mechanical properties, thermal conductivity, or elongation of the aluminum alloy, thereby detrimental to the use of the aluminum alloy as a die-casting material.

According to the aluminum alloy in some embodiments of the present disclosure, the mass ratio of Ti to B is (5-10):1, for example 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. It was found through further experiments that Ti and B in this ratio ensure the high strength and thermal conductivity of the aluminum alloy. The reason is that Ti within this content range is uniformly distributed around the eutectic Si, increasing the strength of the aluminum alloy, and the addition of B in this ratio ensures the high strength with good thermal conductivity.

According to the aluminum alloy in some embodiments of the present disclosure, the content of Ga in percentage by mass is greater than the content of Sr in percentage by mass.

According to the aluminum alloy in some embodiments of the present disclosure, the content of Si and the content of Cu satisfy the following condition: Wt(Si)=(Wt(Cu)−0.2)×(3−5). Under this condition, the formed eutectic Si and Al₂Cu inhibit the growth of the α-Al grains, which become small in diameter.

According to the aluminum alloy in some embodiments of the present disclosure, the content of Mn and the content of Cu satisfy the following condition: Wt(Cu)=(Wt(Mn)−0.3)×(2.5−4). Under this condition, through the induction of Ti—B, Si, Cu, and Mn form a new spherical Si₇Mn₆Cu phase uniformly distributed at the grain boundary, greatly increasing the strength and elongation of the aluminum alloy.

Under the foregoing conditions, a high-strength a solid solution is formed in the aluminum alloy. In this case, Ti, Ga, and B form a fine strengthening phase evenly distributed between the eutectic Si and a solid solution, which greatly increases the yield strength of the aluminum alloy while ensuring the elongation of the aluminum alloy.

According to the aluminum alloy in some embodiments of the present disclosure, the other elements include one or more of Zr, Ni, Ce, Sc, and Er. Zr, Ni, Ce, Sc, and Er are harmful elements that need to be reduced as impurities from the aluminum alloy as much as possible. In some specific embodiments, the aluminum alloy does not include the other elements.

For example, as an impurity element, the solubilization of Ni into a solid solution of the alloy will have a greater impact on Cu, Mn, and Mg, resulting in severe segregation, thereby making the aluminum alloy brittle. Zr, Ce, Er, and Sc form a second phase that cannot be solubilized in the aluminum alloy, so that the distribution of composition of the aluminum alloy is uneven, making the aluminum alloy brittle.

According to another aspect, the present disclosure provides a method for preparing the foregoing aluminum alloy. The method includes the following steps: weighing out various raw materials in required proportions based on proportions of all elements in the aluminum alloy, melting the raw materials in a melting furnace to obtain a molten metal, and subjecting the molten metal to slag removal and refining and degassing, and then casting, to obtain an aluminum alloy ingot. The raw materials include an Al-containing material, a Si-containing material, a Mg-containing material, a Fe-containing material, a Sr-containing material, a Ti-containing material, a B-containing material, a Cu-containing material, a Mn-containing material, a Ga-containing material, a Cr-containing material, and a Zn-containing material. The raw materials are selected from alloys or elements containing the foregoing elements.

In some embodiments, the slag removal includes adding a slag remover into the molten metal, the slag remover including one or more of an aluminum alloy slag remover agent NF-1 and an aluminum alloy slag-removal agent DSG.

In some embodiments, the refining is carried out at 700-710° C. (specifically 700° C., 701° C., 702° C., 703° C., 704° C., 705° C., 706° C., 707° C., 708° C., 709° C., or 710° C.). The refining includes adding a refining agent into the molten metal and stirring. The refining agent includes one or more of hexafluoroethane and an aluminum refining agent ZS-AJ01C.

According to the method in some embodiments of the present disclosure, the method further includes die casting the aluminum alloy ingot for formation.

In some embodiments, the casting is carried out at 680-720° C. (for example 680° C., 690° C., 700° C., 710° C., or 720° C.).

In some embodiments, artificial aging is carried out on the die-cast aluminum alloy at 100-200° C. (for example 100° C., 110° C., 120° C., 130° C., 140° C., 150° C., 160° C., 170° C., 180° C., 190° C., or 200° C.) for 1.5-3 h (for example 1.5 h, 2 h, 2.5 h, or 3 h).

The aluminum alloy is precipitation-hardened by the artificial aging, and the precipitation hardening effect can be observed by testing the mechanical properties of the aluminum alloy. The precipitation of Al₂Cu phase is accelerated at 100-200° C., increasing the strength of the grain boundary, thereby increasing the strength and hardness of the alloy.

The present disclosure is further described through the following examples.

TABLE 1 Inevitable impurities Si Cu Mn Mg Ti Sr Cr Fe Ga B Zn and Al Example 1 9.5 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 2 10 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 3 10.5 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 4 10 2.5 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 5 10 2.6 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 6 10 2.8 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 7 10 2.5 0.9 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 9 10 2.5 1.1 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 10 10 2.5 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 11 10.5 2.5 0.95 0.8 0.04 0.013 0.012 0 0.014 0.005 0 Example 12 10.5 2.5 1 0.9 0.04 0.013 0.012 0 0.014 0.005 0 Example 13 10.5 2.5 0.95 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 14 10.5 2.5 1.1 0.8 0.03 0.013 0.012 0 0.014 0.004 0 Example 15 10.5 2.5 1.1 0.8 0.07 0.013 0.012 0 0.014 0.005 0 Example 16 10.5 2.5 1.1 0.8 0.08 0.013 0.012 0 0.014 0.005 0 Example 17 10.5 2.5 1.1 0.8 0.05 0.013 0.012 0 0.014 0.005 0 Example 18 10.5 2.5 1.1 0.8 0.03 0.013 0.012 0 0.014 0.005 0 Example 19 10.5 2.5 1.1 0.8 0.03 0.013 0.01 0 0.014 0.005 0 Example 20 10.5 2.5 1.1 0.8 0.03 0.013 0.015 0.1 0.014 0.005 0 Example 21 10.5 2.5 1.1 0.8 0.05 0.013 0.012 0.2 0.014 0.005 0.5 Example 22 10.5 2.5 1.1 0.8 0.05 0.013 0.012 0.3 0.014 0.005 1 Example 23 8.5 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 24 10 2.2 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 25 10 2.8 1.4 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 27 10.5 2.5 1.1 0.8 0.03 0.015 0.012 0 0.02 0.005 0 Example 28 10.5 2.5 1.1 1 0.02 0.013 0.012 0 0.014 0.005 0 Example 29 10.5 2.5 1.1 1 0.1 0.013 0.012 0 0.014 0.005 0 Example 30 10.5 2.5 1.1 1 0.04 0.013 0.012 0 0.01 0.005 0 Example 31 10.5 2 1.1 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 32 8 3 1.1 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 33 10.5 2.5 0.8 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 34 10.5 2.5 1.5 1 0.04 0.013 0.012 0 0.014 0.005 0 Comparative 7.8 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 1 Comparative 12 2.7 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 2 Comparative 10 1.8 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 3 Comparative 10 3.5 1.2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 4 Comparative 10 2.5 0.5 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 5 Comparative 10 2.5 2 1 0.04 0.013 0.012 0 0.014 0.005 0 Example 6 Comparative 10 2.5 1 1 0.04 0.013 0.012 0 0 0.005 0 Example 7 Comparative 10.5 2.5 1 0.5 0.04 0.013 0.012 0 0.014 0.005 0 Example 8 Comparative 10.5 2.5 1 1.5 0.04 0.013 0.012 0 0.014 0.005 0 Example 9 Comparative 10.5 2.5 1 0.7 0.15 0.013 0.012 0 0.014 0.005 0 Example 10 Comparative 10.5 2.5 1 0.7 0.03 0.005 0.012 0 0.01 0.005 0 Examnle 11 Comparative 10.5 2.5 1 0.7 0.03 0.013 0 0 0.014 0.005 0 Example 12 Comparative 10.5 2.5 1.1 0.7 0.05 0.013 0.012 0 0.014 0.005 2.3 Example 13 Note: Each composition in Table is in percentage by weight, and the total weight of inevitable impurity elements is less than 0.1%.

Example 1

This example is used to describe the aluminum alloy and the preparation method thereof in the present disclosure, including the following steps:

As shown in Table 1, the components of the aluminum alloy in percentage by mass include: 9.5% of Si, 2.7% of Cu, 1% of Mg, 1.2% of Mn, 0.013% of Sr, 0.012% of Cr, 0% of Fe, 0.04% of Ti, 0.014% of Ga, 0.005% of B, 0% of Zn, and the balance of Al and less than 0.1% of inevitable impurities. The required mass of intermediate alloys or metal elements was calculated based on the mass of the foregoing components of the aluminum alloy, the intermediate alloys or metal elements were melted in a melting furnace to obtain a molten metal, and the molten metal was subjected to slag removal by using a slag remover and was subjected to refining and degassing by using a refining agent at 700-710° C., and then was cast to obtain an aluminum alloy ingot. The aluminum alloy ingot was naturally aged for 7 d to obtain an aluminum alloy.

Examples 2-34

Examples 2-34 are used to describe the aluminum alloy and the preparation method thereof in the present disclosure, including most of the steps in Example 1, and the difference is as follows:

The compositions of the aluminum alloy in Examples 2-34 are shown in Table 1, the required mass of intermediate alloys or metal elements was calculated based on the mass of the foregoing components of the aluminum alloy, the intermediate alloys or metal elements were melted in a melting furnace to obtain a molten metal, and the molten metal was subjected to slag removal by using a slag remover and was subjected to refining and degassing by using a refining agent at 700-710° C., and then was cast to obtain an aluminum alloy ingot. The aluminum alloy ingot was naturally aged for 7 d to obtain an aluminum alloy.

Comparative Example 1

This comparative example is used to compare with the aluminum alloy and the preparation method thereof in the present disclosure, including the following steps:

As shown in Table 1, the components of the aluminum alloy in percentage by mass include: 7.8% of Si, 2.7% of Cu, 1% of Mg, 1.2% of Mn, 0.013% of Sr, 0.012% of Cr, 0% of Fe, 0.04% of Ti, 0.014% of Ga, 0.005% of B, 0% of Zn, and the balance of Al and less than 0.1% of inevitable impurities. The required mass of intermediate alloys or metal elements was calculated based on the mass of the foregoing components of the aluminum alloy, the intermediate alloys or metal elements were melted in a melting furnace to obtain a molten metal, and the molten metal was subjected to slag removal by using a slag remover and was subjected to refining and degassing by using a refining agent at 700-710° C., and then was cast to obtain an aluminum alloy ingot. The aluminum alloy ingot was naturally aged for 7 d to obtain an aluminum alloy.

Comparative Examples 2-13

Comparative Examples 2-13 are used to compare with the aluminum alloy and the preparation method thereof in the present disclosure, including most of the steps in Example 1, and the difference is as follows:

The compositions of the aluminum alloy in Comparative Examples 2-13 are shown in Table 1, the required mass of intermediate alloys or metal elements was calculated based on the mass of the foregoing components of the aluminum alloy, the intermediate alloys or metal elements were melted in a melting furnace to obtain a molten metal, and the molten metal was subjected to slag removal by using a slag remover and was subjected to refining and degassing by using a refining agent at 700-710° C., and then was cast to obtain an aluminum alloy ingot. The aluminum alloy ingot was naturally aged for 7 d to obtain an aluminum alloy.

Performance Test

The aluminum alloy prepared in Example 1 was imaged by using a scanning electron microscope (SEM) to obtain SEM images shown in FIG. 1 and FIG. 2. The area marked with the cross in FIG. 2 was subjected to diffraction to obtain an SEM-diffraction spectrum shown in FIG. 3. The EDS spectrum was analyzed to obtain the composition of the area marked with the cross in FIG. 2, as shown in Table 2.

TABLE 2 Element wt % at % CK 02.52 05.94 OK 01.42 02.52 MgK 00.81 00.95 AlK 71.05 74.60 SiK 07.69 07.76 MnK 12.40 06.39 CuK 04.11 01.83 Matrix Correction ZAF

It can be learned that a spherical Si₇Mn₆Cu phase is formed herein in FIG. 2 and is evenly distributed at the grain boundary, increasing the strength and elongation of the aluminum alloy.

The aluminum alloys prepared in Examples 1-34 and Comparative Examples 1-13 were subjected to the following performance tests:

Tensile test: The yield strength, tensile strength, and elongation were tested according to GBT 228.1-2010 Metallic Materials Tensile Testing Part 1: Room Temperature Test Methods.

Thermal conductivity test: A thermally conductive ingot wafer of ϕ 12.7×3 mm was prepared as a to-be-tested piece, and graphite was evenly sprayed on both sides of the to-be-tested piece to form a coating. The coated piece was tested by using a laser thermal conductivity instrument. The laser thermal conductivity test was carried out in accordance with ASTM E1461 Standard Test Method for Thermal Diffusivity by the Flash Method.

The test results are shown in Table 3.

TABLE 3 Thermal Yield Tensile conductivity strength strength Elongation Die-casting of ingot (MPa) (MPa) (%) formability W/(m · k) Example 1 243 415 5.12 Excellent 137 Example 2 251 418 4.83 Excellent 138 Example 3 255 411 4.53 Excellent 135 Example 4 248 410 4.54 Excellent 132 Example 5 249 413 4.2 Excellent 134 Example 6 252 410 4.48 Excellent 133 Example 7 248 412 4.52 Excellent 138 Example 8 249 418 5.03 Excellent 136 Example 9 251 417 4.93 Excellent 134 Example 10 253 418 4.28 Excellent 132 Example 11 243 418 5.21 Excellent 138 Example 12 249 418 5.02 Excellent 136 Example 13 254 415 4.35 Excellent 135 Example 14 245 413 4.2 Excellent 135 Example 15 251 410 4.35 Excellent 133 Example 16 250 407 4.38 Excellent 135 Example 17 251 421 5.02 Excellent 133 Example 18 245 411 4.82 Excellent 138 Example 19 245 410 4.53 Excellent 136 Example 20 245 413 4.82 Excellent 135 Example 21 247 412 4.35 Excellent 133 Example 22 252 410 4.32 Excellent 132 Example 23 242 403 4.5 Good 135 Example 24 241 405 4.68 Good 136 Example 25 252 401 3.52 Good 130 Example 26 242 398 4.25 Excellent 137 Example 27 243 405 4.52 Excellent 134 Example 28 241 403 4.32 Excellent 132 Example 29 241 405 4.35 Excellent 130 Example 30 251 395 3.8 Excellent 131 Example 31 242 395 3.2 Excellent 131 Example 32 241 385 3.1 Good 131 Example 33 241 386 3.92 Good 132 Example 34 252 392 3.53 Excellent 130 Comparative 241 373 2.8 Average 121 Example 1 Comparative 252 382 2.3 Good 118 Example 2 Comparative 235 375 3.1 Good 118 Example 3 Comparative 252 379 2.23 Average 115 Example 4 Comparative 235 381 2.82 Average 127 Example 5 Comparative 261 370 2.31 Average 115 Example 6 Comparative 241 373 2.85 Good 123 Example 7 Comparative 223 372 3.5 Good 135 Example 8 Comparative 261 371 2.22 Average 115 Example 9 Comparative 236 370 3.38 Good 121 Example 10 Comparative 238 372 3.26 Good 123 Example 11 Comparative 237 369 3.17 Good 125 Example 12 Comparative 237 372 3.18 Good 123 Example 13

It can be learned by comparing the test results of Examples 1-34 with the test results of Comparative Examples 1-13 that, the mechanical strength, thermal conductivity, elongation, and die-casting formability of the aluminum alloy provided in the present disclosure is better than the aluminum alloys beyond the element range provided in the present disclosure. And the aluminum alloy provided in the present disclosure can meet the requirements of the die-casting process.

The foregoing descriptions are merely embodiments of the present disclosure, but are not intended to limit the present disclosure. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present disclosure shall fall within the protection scope of the present disclosure.

Claims

1. An aluminum alloy, in percentage by mass, the aluminum alloy comprising:

8-11% of Si, 2-3% of Cu, 0.7-1.1% of Mg, 0.7-1.5% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.02-0.1% of Ti, 0.01-0.02% of Ga, 0.004-0.02% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

2. The aluminum alloy according to claim 1, in percentage by mass, the aluminum alloy comprising:

9-10.8% of Si, 2.5-2.8% of Cu, 0.7-1.1% of Mg, 0.9-1.3% of Mn, 0.01-0.015% of Sr, 0.01-0.015% of Cr, 0-0.4% of Fe, 0.03-0.1% of Ti, 0.01-0.015% of Ga, 0.004-0.01% of B, 0-2% of Zn, and the balance of Al and less than 0.1% of other elements.

3. The aluminum alloy according to claim 1, wherein a mass ratio of Ti to B is (5-10):1.

4. The aluminum alloy according to claim 1, wherein a content of Ga in percentage by mass is greater than a content of Sr in percentage by mass.

5. The aluminum alloy according to claim 1, wherein a content of Si and a content of Cu satisfy the following condition:

Wt(Si)=(Wt(Cu)−0.2)×(3−5).

6. The aluminum alloy according to claim 1, wherein a content of Mn and a content of Cu satisfy the following condition:

Wt(Cu)=(Wt(Mn)−0.3)×(2.5−4).

7. The aluminum alloy according to claim 1, wherein the other elements comprise one or more of Zr, Ni, Ce, Sc, and Er.

8. A method for preparing the aluminum alloy according to claim 1, comprising the following steps:

weighing out various raw materials in required proportions based on proportions of all elements in the aluminum alloy, melting the raw materials in a melting furnace to obtain a molten metal, and subjecting the molten metal to slag removal and refining and degassing, and then casting, to obtain an aluminum alloy ingot.

9. The method according to claim 8, wherein the slag removal comprises adding a slag remover into the molten metal, the slag remover comprising one or more of an aluminum alloy slag remover agent NF-1 and an aluminum alloy slag-removal agent DSG.

10. The method according to claim 8, wherein the refining is carried out at 700-710° C., and the refining comprises adding a refining agent into the molten metal, the refining agent comprising one or more of hexafluoroethane and an aluminum refining agent ZS-AJ01C.

11. The method according to claim 8, further comprising:

die casting the aluminum alloy ingot for formation.

12. The method according to claim 11, comprising carrying out artificial aging on the die-cast aluminum alloy.

13. The method according to claim 12, wherein the artificial aging is carried out at 100-200° C. for 1.5-3 h.