Die Casting Aluminum Alloys for Heat-Dissipating Plates

Abstract

Provided is an aluminum alloy, and particularly, a die casting aluminum alloy for a heat sink, which includes 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe, 1.0 to 1.5 wt % of Si, and thus may enhance heat dissipation and castability.

Description

TECHNICAL FIELD

The present invention relates to an aluminum alloy, and particularly, to a die casting aluminum alloy for a heat sink, which includes 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe, and 1.0 to 1.5 wt % of Si, and thus can simultaneously enhance heat dissipation and castability.

BACKGROUND ART

Generally, a heat sink part for a car audio is now manufactured using an Al—Si—Cu-based alloy through die casting.

Since such a heat sink part is manufactured of an alloy having excellent castability and low heat dissipation, an audio part can be degraded in heat dissipation.

To solve such a problem, excellent industrial pure aluminum having excellent heat dissipation is suggested.

The pure aluminum had an excellent heat dissipation characteristic (234 W/mK), but had defects after die casting.

In addition, to solve this problem, an Al—Si—Cu-based die casting alloy, an ALDC 12 species, which has excellent fluidity, was provided, but the ALDC 12 species had low heat dissipation (96 W/mK).

DISCLOSURE

Technical Field

The present invention is directed to providing a die casting aluminum alloy for a heat sink, which has excellent heat dissipation and castability.

Technical Solution

One aspect of the present invention provides a die casting aluminum alloy for a heat sink including 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe, and 1.0 to 1.5 wt % of Si.

Here, the aluminum alloy may further include 0.0035 to 0.01 wt % of Mn.

In addition, the aluminum alloy may further include 0.01 to 0.5 wt % of Cu, and 0.3 to 0.6 wt % of Fe.

Advantageous Effects

According to the present invention, heat dissipation and castability can be enhanced.

DESCRIPTION OF DRAWINGS

FIG. 1 is a conceptual diagram of an apparatus for testing fluidity of an aluminum alloy.

FIG. 2 is an image of a fluidity test conducted by the apparatus for a fluidity test.

FIG. 3 is a graph showing test results obtained using the apparatus for the fluidity test.

FIGS. 4 to 6 are images of heat sinks casted using aluminum alloys according to the present invention.

FIG. 7 is a graph showing heat dissipation of the aluminum alloys according to the present invention.

FIG. 8 is an image of an aluminum alloy tissue of the present invention.

MODES OF INVENTION

Before a variety of Examples of the present invention will be described in detail, it can be noted that applications are not limited to detailed descriptions of a configuration and arrangements of components to be described in the detailed description or illustrated in the drawings.

The present invention will be implemented by other Examples, and performed by a variety of methods.

In addition, the expressions and phrases used for the terms indicating directions of an apparatus or factor (e.g., “front,” “back,” “up,” “down,” “top,” “bottom,” “left,” “right,” “lateral,” etc.) are merely used to simplify the description of the present invention, and it can be noted that it does not mean that the related apparatuses or factors simply have a specific directions.

Hereinafter, Examples of the present invention will be described in detail with reference to the following drawings. Beforehand, terminologies used in the specification and claims should not be construed as conventional or literal meanings, but should be construed as meanings and concepts corresponding to the technical idea of the present invention based on the principle in which the inventor can suitably define the concept of a term to explain his own invention by the most preferable method.

Accordingly, the configurations illustrated in Examples and the drawings of the specification are merely the most preferable Example of the present invention, and do not represent the entire technical ideas of the present invention. For this reason, it should be understood that there are various equivalents and modifications that can replace the configurations at the time of application.

The present invention relates to a die casting aluminum alloy for a heat sink including includes 0.01 to 0.5 wt % of Cu, 0.3 to 0.6 wt % of Fe, and 1.0 to 1.5 wt % of Si to simultaneously enhance heat dissipation and casting characteristics as described above.

Here, the aluminum alloy of the present invention may further include 0.0035 to 0.01 wt % of Mn having an effect on thermal conductivity.

In addition, the aluminum alloy may further include 0.0001 to 0.001 wt % of Mg.

Hereinafter, the aluminum alloy of the present invention described above will be compared with Comparative Examples.

TABLE 1
Comparison of Comparative Examples with Examples
	Composition ratio (wt %)
No.	Si	Fe	Cu	Mg	Mn	Al
Comparative	1.058	0.572	1.025	0.0005	0.0032	Bal.
Example 1
Comparative	1.465	0.589	0.543	0.0009	0.0034	Bal.
Example 2
Comparative	0.524	0.612	1.048	0.0004	0.0031	Bal.
Example 3
Example 1	0.992	0.594	0.052	0.0006	0.0041	Bal.
Example2	1.488	0.310	0.048	0.003	0.0038	Bal.

Fluidity Test

A fluidity test was performed to evaluate castability.

For the fluidity test, as shown in FIG. 1, an apparatus for a fluidity test 100 having a sprue 120 formed in the center of a disc-type main body 110 was used.

Here, from the sprue 120 of the main body 110, six linear flow channels 130 spaced certain angles were formed.

Each of the fluid channels 130 had a width W of 5 mm, and a length L of 200 mm.

However, the depths t were respectively 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm.

An alloy corresponding to Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1 or Example 2 was input to the sprue 120 of the test apparatus 100.

FIG. 2A shows the alloy corresponding to Comparative Example 1, FIG. 2B shows the alloy corresponding to Comparative Example 2, FIG. 2C shows Comparative Example 3, FIG. 2D shows the alloy corresponding to Example 1, and FIG. 2E shows the alloy corresponding to Example 2.

FIG. 3 shows flow distances of the alloys for respective channels 130, which are measured by the test apparatus 100.

In other word, a horizontal axis of FIG. 3 shows Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 1, and Example 2, and a vertical axis thereof shows the flow distances of the alloys.

As shown in FIG. 3, the flow distances of Example 1, Example 2, Comparative Example 1 and Comparative Example 2 are 720 mm or more, and it can be confirmed that the alloys had good castability.

It can be noted that, for the sake of the castability, Si should be included in an amount of 1.0 wt % or more.

Test for Confirming Generation of Casting Defects

As another aspect of the castability test, a test was performed to confirm whether defects were generated in a product produced by casting.

The casting was performed in the shape of a heat sink, as shown in FIG. 4.

In addition, conditions for an apparatus for die casting are shown in Table 2.

TABLE 2
Condition for die casting
	Clamping force	Injection force	Accumulator
	1500 kN	490 kN	15.5 Mpa
	Length of sleeve	Diameter of plunger	Packing factor
	425 mm	Φ60	32%

In addition, die casting injection conditions are shown in Table 3.

TABLE 3
Injection conditions
Plunger position (mm) Plunger speed (m/s)
step 1: 120           0.2
step 2: 320           0.8
step 3: 380           1.2
step 4: 410           2.5
step 5: 425           2.5

In Comparative Example 1, by the result of casting under the above conditions, defects were generated in a part represented by a circle in FIG. 5A.

In Comparative Examples 2 and 3, defects were also generated in the parts shown in a circle, respectively.

Such defects are hot tearing defects generated in casting, and representative images of the defects are FIGS. 5D and 5E.

As noted from the test, in Comparative Examples 1, 2 and 3, the above-described defects were generated, but in Examples 1 and 2, the defects were not generated, and excellent castability could be confirmed.

In addition, as confirmed from FIGS. 6A to 6E, in Comparative Examples (FIG. 6A), Comparative Example 2 (FIG. 6B), and Comparative Example 3 (FIG. 6C), defects were not observed, but in Example 1 (FIG. 6D) and Example 2 (FIG. 6E), defects were not observed.

Accordingly, it was noted that the alloys formed in the compositions described in Examples 1 and 2 had excellent castability.

Heat Dissipation Test

For a heat dissipation test, thermal conductivity was analyzed by forming disc-type samples having a diameter of 12.7 mm and a thickness of 2 mm using the alloys manufactured in Comparative Example 2, Examples 1 and 2.

As shown in FIG. 7, the heat conductivities were approximately 150 W/mk in Comparative Example 2, 198.472 W/mK in Example 1, and 185.999 W/mK in Example 2, respectively.

In other words, it can be noted that the alloys of the present invention had considerably higher heat conductivities than that of the ALDC 12, which is 96.2 W/mK, and thus had higher heat dissipation.

As described above, it can be noted that the alloys having the compositions described in Examples 1 and 2 have excellent castability and heat dissipation, and can manufacture a heat sink which is easily casted and has good heat dissipating performance using such alloys.

DESCRIPTION OF REFERENCE NUMERALS

100: Apparatus for fluidity test/110: Main body

Claims

1. A die casting aluminum alloy for a heat sink, comprising: Cu in an amount of 0.01 to 0.5 wt %, Fe in an amount of 0.3 to 0.6 wt %, and Si in an amount of 1.0 to 1.5 wt %.

2. The alloy according to claim 1, further comprising: Mn in an amount of 0.0035 to 0.01 wt %.

3. The alloy according to claim 1, further comprising: Mg in an amount of 0.0001 to 0.001 wt %.