EP3546607A1

EP3546607A1 - Heat conductive aluminium alloy and use thereof

Info

Publication number: EP3546607A1
Application number: EP17874325.8A
Authority: EP
Inventors: Qiang Guo; Yunchun Li; Chunmeng ZHANG; Yongliang XIE
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2016-11-23
Filing date: 2017-10-25
Publication date: 2019-10-02
Also published as: CN108085541B; WO2018095186A1; KR20190073465A; JP2020500265A; US20210108290A1; EP3546607A4; CN108085541A

Abstract

The present disclosure discloses a thermally conductive aluminum alloy and application thereof. The thermally conductive aluminum alloy contains alloying elements, unavoidable impurities and the balance of an aluminum element. Based on the total weight of the thermally conductive aluminum alloy, the alloying elements include: 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr and less than 0.1 wt% of Cu. The thermally conductive aluminum alloy prepared by the present disclosure has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W/(m•K).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present disclosure claims priority to Chinese Patent Application No. 201611038514.1 filed in China on November 23, 2016. The entire content of the above-referenced application is incorporated herein by reference.

FIELD

The present disclosure relates to the technical field of aluminum alloy, and in particular to a thermally conductive aluminum alloy and application thereof.

BACKGROUND

Aluminum alloy materials are widely used in aviation, aerospace, electronic and electrical products, automotive, machinery manufacturing and other fields because of their characteristics of low density, high strength, good plasticity, excellent electrical conductivity, thermal conductivity and corrosion resistance.
Since electronic and electrical products tend to be miniaturized in recent years, the conventional aluminum alloy materials such as ADC12 on the market have a thermal conductivity of only 96 W/(m•K), which has been difficult to meet the demand for high strength and high thermal conductivity of electronic and electrical products. There is an urgent need to develop a new aluminum alloy material that has high thermal conductivity while having the advantages of high mechanical properties and low cost.

SUMMARY

An object of the present disclosure is to provide a thermally conductive aluminum alloy. The thermally conductive aluminum alloy has a high thermal conductivity and can be recycled.
In order to achieve the above object, the present disclosure provides a thermally conductive aluminum alloy, containing alloying elements, unavoidable impurities and the balance of an aluminum element, where based on the total weight of the thermally conductive aluminum alloy, the alloying elements include: 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr and less than 0.1 wt% of Cu.
Through the above technical solution, the thermally conductive aluminum alloy prepared by the present disclosure has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W/(m•K). The thermally conductive aluminum alloy has high mechanical properties and good flow forming property, and the forming fluidity measured by a mosquito coil mold is not less than 1150 mm. The thermally conductive aluminum alloy can be recycled and reused multiple times. The thermal conductivity of the die-casting material after 5 times of recycling is >125 W/(m•K), which is 83% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is >112 W/(m•K), which is 75% or above of the thermal conductivity of the new material.
Optionally, based on the total weight of the thermally conductive aluminum alloy, the alloying elements include: 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than 270 MPa, a yield strength of not less than 160 MPa, an elongation of not less than 5%, and a thermal conductivity of not less than 160 W/(m•K).
Optionally, the impurity elements in the thermally conductive aluminum alloy do not exceed 0.2 wt%.
Optionally, the thermally conductive aluminum alloy consists of 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, not more than 0.2 wt% of impurity elements and the balance of aluminum.
Optionally, the thermally conductive aluminum alloy consists of 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr, less than 0.01 wt% of Cu, not more than 0.2 wt% of impurity elements and the balance of aluminum.
The present disclosure further provides application of the thermally conductive aluminum alloy as described above in the manufacture of metal structural members and/or heat sinks for electronic and electrical products.
Other features and advantages of the present disclosure are described in detail in the Detailed Description part below.

DETAILED DESCRIPTION

Specific implementations of the present disclosure are described in detail below. It should be understood that the specific implementations described herein are merely used to describe and explain the present disclosure rather than limit the present disclosure.
Herein, without any indication to the contrary, the values of tensile strength, yield strength and elongation of a thermally conductive aluminum alloy refer to the tensile strength, yield strength and elongation of a metallic material tested in accordance with GB/T 228.1-2010 Metallic Materials-Tensile Testing-Part 1: Method oftest at room temperature.
A first aspect of the present disclosure provides a thermally conductive aluminum alloy, containing alloying elements, unavoidable impurities and the balance of an aluminum element, where based on the total weight of the thermally conductive aluminum alloy, the alloying elements may include: 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr and less than 0.1 wt% of Cu.
Through the above technical solution, the thermally conductive aluminum alloy prepared by the present disclosure has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W/(m•K). The thermally conductive aluminum alloy has high mechanical properties and good flow forming property, and the forming fluidity measured by a mosquito coil mold is not less than 1150 mm. The thermally conductive aluminum alloy can be recycled and reused multiple times. The thermal conductivity of the die-casting material after 5 times of recycling is not less than 125 W/(m•K), which is 83% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is not less than 112 W/(m•K), which is 75% or above of the thermal conductivity of the new material.
According to the first aspect of the present disclosure, in order to further improve the mechanical properties, thermal conductivity and casting properties of the thermally conductive aluminum alloy, based on the total weight of the thermally conductive aluminum alloy, the alloying elements may include: 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than 270 MPa, a yield strength of not less than 160 MPa, an elongation of not less than 5%, and a thermal conductivity of not less than 160 W/(m•K). The thermal conductivity of the die-casting material after 5 times of recycling is not less than 138 W/(m•K), which is 86% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is not less than 125 W/(m•K), which is 78% or above of the thermal conductivity of the new material.
According to the first aspect of the present disclosure, the purity of the aluminum alloy is one of the important factors affecting the properties of the aluminum alloy. In order to make the thermally conductive aluminum alloy of the present disclosure excellent in properties, the impurity elements in the thermally conductive aluminum alloy do not exceed 0.2 wt%.
According to the first aspect of the present disclosure, in order to further improve the mechanical properties, thermal conductivity and casting properties of the thermally conductive aluminum alloy, the thermally conductive aluminum alloy consists of 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, not more than 0.2 wt% of impurity elements and the balance of aluminum. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W/(m•K). The thermally conductive aluminum alloy has good flow forming property, and the forming fluidity measured by a mosquito coil mold is not less than 1150 mm.
According to the first aspect of the present disclosure, in order to further improve the mechanical properties, thermal conductivity and casting properties of the thermally conductive aluminum alloy, the thermally conductive aluminum alloy consists of 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than 270 MPa, a yield strength of not less than 160 MPa, an elongation of not less than 5%, and a thermal conductivity of not less than 160 W/(m•K). The thermal conductivity of the die-casting material after 5 times of recycling is not less than 138 W/(m•K), which is 86% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is not less than 125 W/(m•K), which is 78% or above of the thermal conductivity of the new material.
A second aspect of the present disclosure provides application of the thermally conductive aluminum alloy as described above in the manufacture of metal structural members and/or heat sinks for electronic and electrical products.
The present invention will be further illustrated by the following embodiments, but the present invention is not limited thereby.

Embodiment 1

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 5.0 parts by weight of Si, 1.0 part by weight of Fe, 0.2 part by weight of Mg, 0.05 part by weight of Zn, 0.05 part by weight of Mn, 0.05 part by weight of Sr, 0.05 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 5.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.2 part by weight of magnesium was finally added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Embodiment 2

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 11.0 parts by weight of Si, 0.4 part by weight of Fe, 1.0 part by weight of Mg, 0.05 part by weight of Zn, 0.05 part by weight of Mn, 0.05 part by weight of Sr, 0.05 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 11.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 1.0 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Embodiment 3

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 8.0 parts by weight of Si, 0.4 part by weight of Fe, 0.4 part by weight of Mg, 0.008 part by weight of Zn, 0.008 part by weight of Mn, 0.05 part by weight of Sr, 0.008 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 8.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.4 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Embodiment 4

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 11.0 parts by weight of Si, 0.6 part by weight of Fe, 0.8 part by weight of Mg, 0.002 part by weight of Zn, 0.002 part by weight of Mn, 0.002 part by weight of Sr, 0.002 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 11.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.8 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Embodiment 5

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 9.5 parts by weight of Si, 0.6 part by weight of Fe, 0.6 part by weight of Mg, 0.005 part by weight of Zn, 0.005 part by weight of Mn, 0.05 part by weight of Sr, 0.005 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 9.5 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.6 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Comparative Example 1

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 4.2 parts by weight of Si, 0.2 part by weight of Fe, 0.4 part by weight of Mg, 0.05 part by weight of Zn, 0.05 part by weight of Mn, 0.05 part by weight of Ni, 0.05 part by weight of Cr and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 4.2 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.4 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Comparative Example 2

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 4.0 parts by weight of Si, 0.2 part by weight of Fe, 0.1 part by weight of Mg, 0.15 part by weight of Zn, 0.15 part by weight of Mn, 0.15 part by weight of Sr, 0.15 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 4.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.1 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Comparative Example 3

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 12.0 parts by weight of Si, 0.2 part by weight of Fe, 0.1 part by weight of Mg, 0.15 part by weight of Zn, 0.15 part by weight of Mn, 0.15 part by weight of Sr, 0.15 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 12.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 0.1 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Comparative Example 4

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as 100 parts by weight, the thermally conductive aluminum alloy contains 4.0 parts by weight of Si, 1.2 parts by weight of Fe, 1.0 part by weight of Mg, 0.15 part by weight of Zn, 0.15 part by weight of Mn, 0.15 part by weight of Sr, 0.15 part by weight of Cu and the balance of Al.
First, the furnace was preheated at 400°C for 25 minutes and purged with argon gas, the corresponding parts by weight of pure aluminum ingot was added for melting, and when the temperature of the pure aluminum liquid reached 800°C, the pure aluminum liquid was allowed to stand for 25 minutes to fully melt the pure aluminum ingot. The furnace was cooled to 760°C, 4.0 parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for 25 minutes, and after melting, stirring was continued for 15 minutes. When the furnace was cooled to 700°C, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, 1.0 part by weight of magnesium was added, after melting was completed, stirring was continued for 8 minutes, the dross was removed, a refining agent was added at 700°C for refining, and the mixture was stirred for 15 minutes. Then, the ladle composition analysis was carried out to inspect the component content of the alloy, and the melt which is unqualified in the component content was subjected to feeding or dilution for reaching standards, so as to obtain the thermally conductive aluminum alloy of this embodiment.

Test Embodiment 1

This test embodiment is used to determine the mechanical properties, thermal conductivity and flow formability at room temperature of the thermally conductive aluminum alloys obtained in Embodiments 1 to 5 and Comparative Examples 1 to 4.
Determination of thermal conductivity: The thermally conductive aluminum alloy in each of the embodiments and comparative examples was prepared into a circular sample having a diameter of 12.7 mm and a thickness of 25.4 mm; a graphite coating was uniformly sprayed on both sides of the sample to be tested; and the treated sample was placed in a laser thermal conductivity tester for testing. The test was performed in accordance with ASTM E1461 Standard Test Method for Thermal Diffusivity by the Flash Method. The specific test results are shown in Table 1.
The tensile strength, yield strength and elongation of the aluminum alloy were tested in accordance with GB/T 228.1-2010 Metallic Materials-Tensile Testing-Part 1: Method of test at room temperature. The sheets extruded in Embodiments 1 to 5 and Comparative Examples 1 to 4 were subjected to wire-cutting to prepare standard tensile samples, and the axial direction of the tensile specimens was consistent with the extrusion direction. The specific test results are shown in Table 1.

The fluidity of the thermally conductive aluminum alloy material was determined by a mosquito coil mold: The mosquito coil mold was a mold having a mold cavity in a mosquito coil shape, and the formed metal member had a spiral shape. The thermally conductive aluminum alloys of Embodiments 1 to 5 and Comparative Examples 1 to 4 were smelted at 730°C, and after being completely melted, they were air-cooled to 690°C and cast into a mosquito coil mold for a fluidity test. The length of the formed aluminum alloy spiral sample was measured. The specific results are shown in Table 1.

Table 1

Example	Thermal Conductivity (W/(m•K))	Tensile Strength (MPa)	Yield Strength (MPa)	Elongation (%)	Forming Fluidity (mm)
Embodiment 1	150	260	151	3.5	1200
Embodiment 2	153	270	162	4.0	1150
Embodiment 3	164	270	169	5.5	1200
Embodiment 4	165	287	178	5.0	1220
Embodiment 5	169	275	172	6.0	1250
Comparative Example 1	93	220	159	2.6	1000
Comparative Example 2	100	239	147	2.0	980
Comparative Example 3	123	253	153	3.9	1050
Comparative Example 4	130	268	150	2.8	1100

It can be seen from the comparison of the results of Embodiments 1 to 5 and Comparative Examples 1 to 4 that the thermally conductive aluminum alloy prepared by the present disclosure has better mechanical properties: the tensile strength is not less than 250 MPa, the yield strength is not less than 150 MPa, and the elongation is not less than 3.5%. While having good mechanical properties, the thermally conductive aluminum alloy has good flow forming property, and the forming fluidity measured by a mosquito coil mold is not less than 1150 mm. The thermal conductivity is not less than 150 W/(m•K). In particular, when the thermally conductive aluminum alloy contains 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu, the prepared thermally conductive aluminum alloy has a tensile strength of not less than 270 MPa, a yield strength of not less than 160 MPa, an elongation of not less than 5% and a thermal conductivity of not less than 160 W/(m•K).

Test Embodiment 2

This test embodiment is used to determine the thermal conductivity of the thermally conductive aluminum alloys obtained in Embodiments 1 to 5 and Comparative Examples 1 to 4 after recycling.

Recycling of thermally conductive aluminum alloy: The new material thermally conductive aluminum alloy in each of the embodiments and comparative examples was separately collected and melted at 760°C for 1 hour; the molten material was placed in a crucible and mechanically stirred at a rate of 1200 rpm for 30 min, and then cooled to obtain the recycled thermally conductive aluminum alloy; and the thermal conductivity of the aluminum alloy after 5 and 10 times of recycling was measured with reference to the thermal conductivity measurement method in Test Embodiment 1. The specific test results are shown in Table 2.

Table 2

Example	Thermal Conductivity after Recycling n times (W/(m•K))
Example	5 times	10 times
Embodiment 1	125	112
Embodiment 2	127	117
Embodiment 3	138	125
Embodiment 4	140	131
Embodiment 5	149	137
Comparative Example 1	78	69
Comparative Example 2	84	77
Comparative Example 3	98	90
Comparative Example 4	107	99

It can be seen from the comparison of the results of Embodiments 1 to 5 and Comparative Examples 1 to 4 that the thermally conductive aluminum alloy prepared by the present disclosure can be recycled and reused multiple times. The thermal conductivity of the die-casting material after 5 times of recycling is not less than 125 W/(m•K), which is 83% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is not less than 112 W/(m•K), which is 75% or above of the thermal conductivity of the new material. In particular, when the thermally conductive aluminum alloy contains 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu, the thermal conductivity of the die-casting material after 5 times of recycling of the thermally conductive aluminum alloy is not less than 138 W/(m•K), which is 86% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after 10 times of recycling is not less than 125 W/(m•K), which is 78% or above of the thermal conductivity of the new material.
Although preferred implementations of the present disclosure are described in detail above, the present disclosure is not limited to specific details in the foregoing implementations. Various simple variations can be made to the technical solutions of the present disclosure within the scope of the technical idea of the present disclosure, and such simple variations all fall within the protection scope of the present disclosure.
It should be further noted that the specific technical features described in the foregoing specific implementations can be combined in any appropriate manner provided that no conflict occurs. To avoid unnecessary repetition, various possible combination manners are not further described in the present disclosure.
In addition, various different implementations of the present disclosure may alternatively be combined randomly. Such combinations should also be considered as the content disclosed in the present disclosure provided that these combinations do not depart from the concept of the present disclosure.

Claims

A thermally conductive aluminum alloy, containing alloying elements, unavoidable impurities and the balance of an aluminum element, wherein based on the total weight of the thermally conductive aluminum alloy, the alloying elements comprise: 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr and less than 0.1 wt% of Cu.
The thermally conductive aluminum alloy according to claim 1, wherein based on the total weight of the thermally conductive aluminum alloy, the alloying elements comprise: 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr and less than 0.01 wt% of Cu.
The thermally conductive aluminum alloy according to claim 1 or 2, wherein the impurity elements in the thermally conductive aluminum alloy do not exceed 0.2 wt%.
The thermally conductive aluminum alloy according to claim 1, wherein the thermally conductive aluminum alloy consists of 5.0 to 11.0 wt% of Si, 0.4 to 1.0 wt% of Fe, 0.2 to 1.0 wt% of Mg, less than 0.1 wt% of Zn, less than 0.1 wt% of Mn, less than 0.1 wt% of Sr, less than 0.1 wt% of Cu, not more than 0.2 wt% of impurity elements and the balance of aluminum.
The thermally conductive aluminum alloy according to claim 2, wherein the thermally conductive aluminum alloy consists of 8.0 to 11.0 wt% of Si, 0.4 to 0.6 wt% of Fe, 0.4 to 0.8 wt% of Mg, less than 0.01 wt% of Zn, less than 0.01 wt% of Mn, less than 0.1 wt% of Sr, less than 0.01 wt% of Cu, not more than 0.2 wt% of impurity elements and the balance of aluminum.
The thermally conductive aluminum alloy according to claim 1, 2, 4 or 5, wherein the thermally conductive aluminum alloy has a tensile strength of not less than 250 MPa, a yield strength of not less than 150 MPa, an elongation of not less than 3.5%, and a thermal conductivity of not less than 150 W/(m•K).
The thermally conductive aluminum alloy according to claim 2 or 5, wherein the thermally conductive aluminum alloy has a tensile strength of not less than 270 MPa, a yield strength of not less than 160 MPa, an elongation of not less than 5%, and a thermal conductivity of not less than 160 W/(m•K).
Application of the thermally conductive aluminum alloy according to any of claims 1 to 7 in the manufacture of metal structural members and/or heat sinks for electronic and electrical products.