JP2002309329A - Al-Mg-Si ALLOY EXTRUSION SHAPE MATERIAL HAVING EXCELLENT HEAT CONDUCTIVITY - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extruded product of an Al-Mg-Si alloy whose heat radiability can be improved without reducing its strength. SOLUTION: The extruded product of Al-Mg-Si alloy having excellent heat conductivity consists of an aluminum alloy having a composition containing, by mass, 0.4 to 0.6% Mg, 0.2 to 0.5% Si, 0.003 to 0.01% Ti, <=0.1% Fe and <=0.005% V, and the balance Al with inevitable impurities.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Al--Mg--Si having excellent thermal conductivity, for example, used as a heat sink for cooling a heating element used in electronic equipment of a computer.
The present invention relates to an extruded aluminum alloy.

[0002]

2. Description of the Related Art In general, a heat sink for cooling a heating element used in electronic equipment such as a computer uses an Al-Mg-Si type, that is, 6000 type aluminum alloy extruded material. In particular, among the 6000 series aluminum alloys, A6063 alloy (JIS) which has excellent heat conductivity, has good extrudability, and has appropriate strength by heat treatment, and can facilitate cutting such as cutting and drilling (JIS). Are widely used.
JP-A-744428 describes a heat sink made of A6063S-T5 material.

[0003]

However, in recent years, electronic devices such as computers have become lighter and smaller, and the amount of heat generated has increased due to higher performance of an internal CPU (central processing unit) and the like. Therefore, it is desired to improve the heat radiation performance of a heat sink for cooling a heating element. However, the conventional A6063 alloy may not be able to sufficiently satisfy the heat radiation performance.

[0004] Further, when a thin-walled portion is formed of a 1000-series aluminum alloy having good thermal conductivity, the strength is low, and there is a problem in that a problem occurs during cutting, and a breakage occurs due to vibration or impact during assembly or use.

[0005] Therefore, an object of the present invention is to provide an extruded Al-Mg-Si-based aluminum alloy material capable of improving heat radiation performance without reducing strength.

[0006]

Means for Solving the Problems An Al having excellent thermal conductivity according to the present invention, which has been taken in order to solve the above technical problems.
-Extruded Mg-Si based aluminum alloy material is Mg:
0.4-0.6%, Si: 0.2-0.5%, Ti:
0.003 to 0.01%, Fe: 0.1% or less, V:
0.005% or less, and the balance is made of Al and an unavoidable impurity of an aluminum alloy.

Here, it is preferable that the aluminum alloy is subjected to an artificial aging treatment after the extrusion, so that the Vickers hardness is 60 HV or more.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, Al-Mg-
The significance of the additional elements in the extruded Si-based aluminum alloy and the reasons for limiting the alloy composition will be described.

(Mg, Si) Mg and Si are Mg ₂ Si
To improve the strength. If the added amount of Mg is less than 0.4% or the added amount of Si is less than 0.2%, Mg ₂ Si
And sufficient strength cannot be obtained. on the other hand,
If the added amount of Mg exceeds 0.6% or the added amount of Si exceeds 0.5%, the thermal conductivity decreases. In consideration of the extrudability, the upper limit of the amount of added Mg is 0.5%,
The upper limit of the amount of i added is preferably 0.4%.

[0010] (Ti) Ti is added for refining the ingot structure, but if it exceeds 0.01%, the thermal conductivity is reduced, and if it is less than 0.003%, casting cracks occur during alloy casting. Cause it to occur. Therefore, the amount of addition is 0.003-0.
01 is desirable. A more desirable addition amount is 0.003 to
0.008%.

(Fe) Fe is the element which is most often mixed as an impurity in the process of refining and casting aluminum, but is preferably 0.1% or less because it greatly reduces the thermal conductivity. More preferably, the content is 0.05% or less.

(V) V is an element mixed as an impurity like Fe, but even a minute amount significantly lowers the thermal conductivity. Therefore, the addition amount is desirably 0.005% or less.

The elements other than those described above have little effect on the properties of the alloy if they are individually 0.05% or less as unavoidable impurities and 0.15% or less in total. However,
Cu, Mn, Cr, Zn, and Zr are each preferably limited to 0.03% or less in order to reduce thermal conductivity.

Although an aluminum alloy extruded material having excellent thermal conductivity can be obtained by using an aluminum alloy adjusted by the above alloy composition by a conventional method, the aluminum alloy extruded material according to the present invention can be obtained. In order to make the most of the characteristics described above, the following manufacturing conditions are desirable.

An aluminum alloy billet having the above composition is melted and homogenized at 540 to 590 ° C. for 2 to 10 hours. Then, after being heated to 450 to 520 ° C., it was extruded, and was cooled by air cooling as it was.
The Vickers hardness is preferably 60 HV or more by performing artificial aging treatment at 220 ° C. for 1 to 5 hours.

Here, the Vickers hardness is measured by:
This is because Vickers hardness is generally treated as a substitute for mechanical properties, particularly tensile strength, after heat treatment in a 6000 series aluminum alloy including the extruded aluminum alloy material according to the present invention. 60HV
If it is less than the strength, it will not be strong enough, and problems such as plastic deformation and burr will occur during cutting and drilling, and in the case of extruded aluminum alloy material with a thin part, it will be damaged during assembly and use, Improper.

[0017]

Next, examples of the present invention will be specifically described in comparison with comparative examples.

Aluminum alloy billets (diameter φ204 mm) of each composition shown in Table 1 were melted by a conventional method, and 570
A homogenization treatment was performed at 5 ° C. for 5 hours. Next, the extrusion temperature (billet heating temperature) was set to 500 ° C., and the extrusion speed was set to 10 m /
Extrusion in min, and after cooling by air cooling as it is,
An artificial aging treatment was performed at 200 ° C. for 3 hours to produce an aluminum alloy extruded shape having a cross section having a plurality of thin portions as shown in FIG.

[0019]

[Table 1]

These extruded aluminum alloy members were cut to a length of 50 mm in the extrusion direction and punched.
Evaluate the cutting workability during this cutting and drilling,
If the extruded shape is plastically deformed or burrs are generated,
A sample that was well cut without any plastic deformation or burrs was judged to be good.

In the evaluation of thermal conductivity, a metal material generally has a proportional relationship between the thermal conductivity and the electrical conductivity, and the quality of the thermal conductivity can be determined based on the electrical conductivity. did. Since the representative value of the conventional A6063 alloy is 54 to 55% IACS, the conductivity is 55% IAC.
S and below were evaluated as x, and those exceeding 55% IACS were evaluated as ○.

Vickers hardness is JIS Z 22 at room temperature.
The measurement was carried out by averaging the five points according to 44. These evaluation results are also shown in Table 2.

[0023]

[Table 2]

As shown in Table 2, Examples 1 and 2, which are the extruded aluminum alloy material according to the present invention, exhibited both good machinability and electrical conductivity. In particular, the typical value of the conductivity of a 1000 series aluminum alloy is 60 to 62% IAC.
Considering that S is the value, it can be seen that the value of 58 to 59% IACS in the 6000 series aluminum alloy has excellent thermal conductivity.

On the other hand, the Vickers hardness is 60 HV
In Comparative Examples 3 and 5, which are less than the above, deformation and burrs of the extruded material occur during cutting and drilling, and Comparative Examples 4 and 7 have good machinability but low electrical conductivity and thermal conductivity. Became inferior.

[0026]

As described above, according to the present invention, an extruded aluminum alloy having excellent heat conductivity while satisfying strength and machinability and suitable as a material for a heat sink for cooling a heating element, for example. Material can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an extruded profile used in an example.

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Claims (2)

[Claims] 1. Mg: 0.4 to 0.6% (mass%, the same applies hereinafter), Si: 0.2 to 0.5%, Ti: 0.003 to
Al having excellent thermal conductivity, comprising 0.01%, Fe: 0.1% or less, V: 0.005% or less, the balance being Al and an aluminum alloy which is an unavoidable impurity.
-Extruded Mg-Si aluminum alloy material. 2. The heat conductive Al-Mg according to claim 1, wherein the aluminum alloy is subjected to an artificial aging treatment after being extruded to have a Vickers hardness of 60 HV or more. -Extruded Si-based aluminum alloy.