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

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 <NUM> 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. <CIT> discloses aluminium-silicon alloys.

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: <NUM> to <NUM> wt% of Si, <NUM> to <NUM> wt% of Fe, <NUM> to <NUM> wt% of Mg, less than <NUM> wt% of Zn, less than <NUM> wt% of Mn, less than <NUM> wt% of Sr and less than <NUM> wt% of Cu. as defined in the appended claim <NUM>.

Through the above technical solution, the thermally conductive aluminum alloy prepared by the present disclosure has a tensile strength of not less than <NUM> MPa, a yield strength of not less than <NUM> MPa, an elongation of not less than <NUM>%, and a thermal conductivity of not less than <NUM> 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 <NUM>. The thermally conductive aluminum alloy can be recycled and reused multiple times. The thermal conductivity of the die-casting material after <NUM> times of recycling is ><NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after <NUM> times of recycling is ><NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than <NUM> MPa, a yield strength of not less than <NUM> MPa, an elongation of not less than <NUM>%, and a thermal conductivity of not less than <NUM> W/(m•K).

Optionally, the impurity elements in the thermally conductive aluminum alloy do not exceed <NUM> wt%.

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.

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 <CIT> Metallic Materials-Tensile Testing-Part <NUM>: Method of test 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, as defined in claim <NUM>.

Through the above technical solution, the thermally conductive aluminum alloy prepared by the present disclosure has a tensile strength of not less than <NUM> MPa, a yield strength of not less than <NUM> MPa, an elongation of not less than <NUM>%, and a thermal conductivity of not less than <NUM> 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 <NUM>. The thermally conductive aluminum alloy can be recycled and reused multiple times. The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material.

According to 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 <NUM> wt%. The thermally conductive aluminum alloy prepared according to the formula has a tensile strength of not less than <NUM> MPa, a yield strength of not less than <NUM> MPa, an elongation of not less than <NUM>%, and a thermal conductivity of not less than <NUM> W/(m•K). The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% 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, and comparative examples but the present invention is not limited thereby.

In this embodiment, based on the total weight of the thermally conductive aluminum alloy as <NUM> parts by weight, the thermally conductive aluminum alloy contains <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al.

First, the furnace was preheated at <NUM> for <NUM> 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 <NUM>, the pure aluminum liquid was allowed to stand for <NUM> minutes to fully melt the pure aluminum ingot. The furnace was cooled to <NUM>, <NUM> parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for <NUM> minutes, and after melting, stirring was continued for <NUM> minutes. When the furnace was cooled to <NUM>, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, <NUM> part by weight of magnesium was finally added, after melting was completed, stirring was continued for <NUM> minutes, the dross was removed, a refining agent was added at <NUM> for refining, and the mixture was stirred for <NUM> 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.

First, the furnace was preheated at <NUM> for <NUM> 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 <NUM>, the pure aluminum liquid was allowed to stand for <NUM> minutes to fully melt the pure aluminum ingot. The furnace was cooled to <NUM>, <NUM> parts by weight of pure silicon was added, and the mixture was allowed to stand at a constant temperature for <NUM> minutes, and after melting, stirring was continued for <NUM> minutes. When the furnace was cooled to <NUM>, the remaining intermediate alloy was added, and after melting was completed, the mixture was allowed to stand. Finally, <NUM> part by weight of magnesium was added, after melting was completed, stirring was continued for <NUM> minutes, the dross was removed, a refining agent was added at <NUM> for refining, and the mixture was stirred for <NUM> 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.

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as <NUM> parts by weight, the thermally conductive aluminum alloy contains <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Ni, <NUM> part by weight of Cr and the balance of Al.

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as <NUM> parts by weight, the thermally conductive aluminum alloy contains <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al.

In this comparative example, based on the total weight of the thermally conductive aluminum alloy as <NUM> parts by weight, the thermally conductive aluminum alloy contains <NUM> parts by weight of Si, <NUM> parts by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al.

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 <NUM> to <NUM> and Comparative Examples <NUM> to <NUM>.

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 <NUM> and a thickness of <NUM>; 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 <NUM>.

The tensile strength, yield strength and elongation of the aluminum alloy were tested in accordance with <CIT> Metallic Materials-Tensile Testing-Part <NUM>: Method of test at room temperature. The sheets extruded in Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> 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 <NUM>.

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 <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> were smelted at <NUM>, and after being completely melted, they were air-cooled to <NUM> 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 <NUM>.

It can be seen from the comparison of the results of Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> that the thermally conductive aluminum alloy prepared by the present disclosure has better mechanical properties: the tensile strength is not less than <NUM> MPa, the yield strength is not less than <NUM> MPa, and the elongation is not less than <NUM>%. 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 <NUM>. The thermal conductivity is not less than <NUM> W/(m•K). In particular, when the thermally conductive aluminum alloy contains <NUM> to <NUM> wt% of Si, <NUM> to <NUM> wt% of Fe, <NUM> to <NUM> wt% of Mg, less than <NUM> wt% of Zn, less than <NUM> wt% of Mn, less than <NUM> wt% of Sr and less than <NUM> wt% of Cu, the prepared thermally conductive aluminum alloy has a tensile strength of not less than <NUM> MPa, a yield strength of not less than <NUM> MPa, an elongation of not less than <NUM>% and a thermal conductivity of not less than <NUM> W/(m•K).

This test embodiment is used to determine the thermal conductivity of the thermally conductive aluminum alloys obtained in Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> 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 <NUM> for <NUM> hour; the molten material was placed in a crucible and mechanically stirred at a rate of <NUM> rpm for <NUM>, and then cooled to obtain the recycled thermally conductive aluminum alloy; and the thermal conductivity of the aluminum alloy after <NUM> and <NUM> times of recycling was measured with reference to the thermal conductivity measurement method in Test Embodiment <NUM>. The specific test results are shown in Table <NUM>.

"Embodiment <NUM>" and "Embodiment <NUM>" in the table actually refer to "Comparative example <NUM>" and "Comparative example <NUM>".

It can be seen from the comparison of the results of Embodiments <NUM> to <NUM> and Comparative Examples <NUM> to <NUM> 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 <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. In particular, when the thermally conductive aluminum alloy contains <NUM> to <NUM> wt% of Si, <NUM> to <NUM> wt% of Fe, <NUM> to <NUM> wt% of Mg, less than <NUM> wt% of Zn, less than <NUM> wt% of Mn, less than <NUM> wt% of Sr and less than <NUM> wt% of Cu, the thermal conductivity of the die-casting material after <NUM> times of recycling of the thermally conductive aluminum alloy is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material. The thermal conductivity of the die-casting material after <NUM> times of recycling is not less than <NUM> W/(m•K), which is <NUM>% or above of the thermal conductivity of the new material.

Claim 1:
A thermally conductive aluminum alloy, wherein the thermally conductive aluminum alloy consists of
a) <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al;
or b) <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al; or
c) contains <NUM> parts by weight of Si, <NUM> part by weight of Fe, <NUM> part by weight of Mg, <NUM> part by weight of Zn, <NUM> part by weight of Mn, <NUM> part by weight of Sr, <NUM> part by weight of Cu and the balance of Al.