JPH059621A - Alumina-Boria whisker reinforced Al-based composite material - Google Patents

Abstract

(57) [Abstract] [Purpose] High strength alumina-Boria whisker reinforced Al
A matrix composite material is obtained. [Constitution] Alumina-Boria whisker is used as a reinforcing material, and M
Alumina with Al alloy containing g as matrix
Boria whisker reinforced Al-based composite material. The Al alloy contains 0.03 to 0.8 wt% B. The Mg in the matrix also reacts with B in the matrix to suppress the reaction between B ₂ O ₃ in the alumina-boria whiskers and Mg in the matrix. The reduction in the strength of the whiskers caused by is avoided.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to composite materials, and more particularly to alumina-boria whisker reinforced Al matrix composites.

[0002]

2. Description of the Related Art As one of Al-based composite materials, for example, "Interface in Whisker-Reinforced Aluminum-based Composite Material", which was distributed on April 23, 1990, by the Wetability Subcommittee Committee of the Composite Materials Subcommittee of the Japan Institute of Light Metals. As described in the article entitled “Structure”, alumina-boria whiskers (aluminum borate whiskers) are used as reinforcements, and A6061 alloy and J
Al-based composite materials having an Al alloy such as the IS standard AC8A alloy as a matrix are already known.

Since alumina-boria whisker is a very inexpensive reinforcing material, alumina-boria whisker reinforced Al is used.
According to the base composite material, it is possible to obtain a composite material that is much cheaper than, for example, a composite material using SiC whiskers as a reinforcing material.

[0004]

However, it has been found that in a composite material containing alumina-boria whiskers as a reinforcing material and Al alloy as a matrix, sufficient strength cannot be obtained depending on the type of Al alloy used. .

The inventor of the present invention has conducted a detailed experimental study on the cause of insufficient strength of the alumina-boria whisker reinforced Al-based composite material depending on the type of Al alloy used. And the tendency to form oxides is small, alumina-boria whiskers (9Al ₂ O ₃
Together · 2B ₂ O ₃₎ in B ₂ O ₃ reacts with Mg in the Al alloy according to _{B 2 O 3 + 3Mg → 3MgO} + 2B, thereby spinel on the surface of the whiskers (MgO · Al ₂ O ₃₎ layer is produced It was investigated that the strength of the whiskers was significantly reduced, and therefore the strength of the composite material was reduced, and that the use of an Al alloy containing a predetermined amount of B as a matrix can prevent the strength reduction of the composite material. I found it.

An object of the present invention is to provide a high-strength alumina-boria whisker reinforced Al-based composite material based on the knowledge obtained as a result of an experimental study conducted by the present inventors.

[0007]

According to the present invention, the above object is to use alumina-boria whiskers as a reinforcing material,
Using an Al alloy containing Mg as a matrix,
The alloy is achieved by an alumina-boria whisker reinforced Al matrix composite characterized by containing 0.03 to 0.8 wt% B.

[0008]

According to the present invention, 0.03 is used as the matrix.
The use of an Al alloy containing 0.8 wt% of B causes a decrease in strength of the alumina-boria whisker reinforced Al-based composite material, as will be apparent from the results of an experimental study conducted by the inventor of the present invention described later. Is prevented. Thus, the mechanism by which the strength reduction of the composite material is prevented is not always clear, but Mg in the matrix is also reacted with B in the matrix, so that B ₂ O ₃ in the alumina-boria whiskers and Mg in the matrix are
It is presumed that the reaction between and is suppressed, the generation of the spinel layer and the resulting reduction in the strength of the whiskers are avoided, and thus the reduction in the strength of the composite material is prevented.
In an extreme case, when B is saturated in an Al alloy as a matrix, B in alumina-boria whiskers is
It is considered that the decomposition of ₂ O ₃ prevents the transfer of B into the Al alloy. Therefore, when a predetermined amount of B is added to the Al alloy, B is transferred from the alumina-boria whiskers into the Al alloy. It is speculated that this will be suppressed.

[0009]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0010]Example 1  First, as shown in FIG. 1, alumina-boriaui
Ska 10 ("Arbolex manufactured by Shikoku Chemicals Co., Ltd.
G ", whisker diameter 0.5-1 μm, whisker length 10-3
(0 μm) into distilled water 12 to fully disintegrate whiskers.
The distilled water and whiskers with a propeller 14 until
After stirring, move the whiskers into the molding jig for compression molding.
Molding with dimensions of 100 × 38 × 16 mm
The body is formed, and the molded body is cooled together with the jig at -50 ° C.
Put it in a freezer and let the water in the molded body freeze sufficiently.
Held until

Next, the molded body was taken out from the jig, and as shown in FIG. 2, the inner dimension was 38 × 16 mm and the length was 140 mm. Was integrally provided in a case 18 made of stainless steel (JIS standard SUS304) with the molded body 20 formed as described above. Then, the molded body together with the case was heated by a heater to sufficiently dry the molded body.

In this way, 13 compacts having a volume ratio of alumina-boria whiskers of 30% were formed.

Next, each molded body is placed in a case at 600 ° C.
After preheating for a period of time, as shown in FIG. 3, the compact 20 is placed in a mold 24 of a high-pressure casting device 22 together with the case, and an Al alloy (Al-4 wt% Cu-1 wt% at 850 ° C.) is placed in the mold.
% Mg-0, 0.01, 0.03, 0.05, 0.1
A molten metal 26 of 0.9 wt% Mg (every 0.1 wt%) is poured, and a plunger 28 for fitting the molten metal into a mold is used to make about 1
Pressurization was performed at a pressure of 000 kgf / cm ² , and the pressurized state was maintained until the molten metal completely solidified. After the molten metal is completely solidified, a knockout pin 30 is used to remove the solidified body from the mold 24, and the solidified body is machined to form an alumina-
A composite material made of Al alloy which was composite-reinforced with boria whiskers was cut out, and heat treatment T6 was applied to each composite material.

Next, bending test pieces were formed from each composite material, and each test piece was subjected to a three-point bending test at room temperature with a fulcrum distance of 40 mm. The results of these tests are shown in FIG.
From FIG. 4, in order to obtain a composite material having excellent strength, the Al alloy as the matrix metal preferably contains B, and the B content is 0.03 to 0.8 wt%, particularly 0.05. It can be seen that the content is preferably 0.8 wt%.

[0015]Example 2  Al alloy with a hot water temperature of 750 ° C (A
1-5 wt% Cu-1.5 wt% Mg-0.1 wt% B)
Hot water is used and the volume ratio of alumina-boria whiskers is 1
Example except that it was set to 5 to 45% (every 5%)
Form a composite material under the same procedure and conditions as in case 1,
T6 heat treatment is applied to each composite material,
The test specimens were formed as in Example 1 for each test specimen.
A three-point bending test was conducted under the same procedure and conditions.

The results of these tests are shown in FIG. From FIG. 5, in order to obtain a composite material having excellent strength, alumina-
It is understood that the volume ratio of boria whiskers is preferably 20 to 40%.

[0017]Example 3  Al alloy with a hot water temperature of 850 ° C (A
1-5 wt% Cu-0.5 to 4.0 wt% Mg-0 wt% B,
Mg content is 0.25 wt%) and hot water temperature is 850 ℃ A
1 alloy (Al-5 wt% Cu-0.5 to 4.0 wt% Mg-
0.4wt% B, Mg content is 0.25wt%)
Is used, and the volume ratio of alumina-boria whiskers is 25.
The same procedure as in Example 1 except that the percentage is set
And the conditions are used to form composite materials, and T6 is applied to each composite material.
Heat treatment is applied to form bending test pieces from each composite material.
For the test piece, follow the same procedure and conditions as in Example 1.
A 3-point bending test was performed.

The results of these tests are shown in FIG. From FIG. 6, it is preferable that the Mg content of the Al alloy is 0.5 to 3.5 wt% in order to obtain the composite material having excellent strength by adding B to the Al alloy as the matrix. I understand.

[0019]Example 4  Al alloy with a hot water temperature of 800 ° C as the matrix metal (J
IS standard 2024) and Al alloy (0.
A JIS standard 2024) melt containing 3 wt% B is added
Except for the points used, the same procedure as in Example 1 and
A composite material is formed under the conditions, and T6 heat treatment is performed on each composite material.
The same as in Example 1 for each composite material.
A three-point bending test was conducted under the conditions and conditions.

The results of these tests are shown in FIG. It can be seen from FIG. 7 that even when the composition of the Al alloy as the matrix is different from the composition of the Al alloy of Example 1, by adding B to the Al alloy, a composite material having excellent strength can be obtained.

Although the present invention has been described above in detail with reference to specific embodiments, the present invention is not limited to these embodiments, and various other embodiments within the scope of the present invention. It will be apparent to those skilled in the art that

[0022]

As is apparent from the above description, according to the present invention, the matrix is 0.03 to 0.8 wt%.
By using the Al alloy containing B, the reaction between B ₂ O ₃ in the alumina-boria whisker and Mg in the matrix is suppressed, and the formation of the spinel layer and the resulting reduction in the strength of the whisker. Is avoided and the migration of B from the alumina-boria whiskers into the matrix is suppressed, so that a high-strength alumina-boria whisker reinforced Al-based composite material can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a defibration process of alumina-boria whiskers.

FIG. 2 is a vertical sectional view showing a molded body of alumina-boria whiskers housed in a case.

FIG. 3 is a vertical cross-sectional view showing a high-pressure casting process performed using the alumina-boria whisker compact shown in FIG.

FIG. 4 is a graph showing the relationship between the B content of an Al alloy and the bending strength of a composite material.

FIG. 5 is a graph showing the relationship between the volume ratio of alumina-boria whiskers and the bending strength of a composite material.

FIG. 6 is a graph showing the relationship between the Mg content of an Al alloy and the bending strength of a composite material.

FIG. 7 is a graph showing the bending strength of a composite material containing two kinds of Al alloys having a B content of 0.3 wt% and 0 wt% as a matrix metal.

[Explanation of symbols]

 10 ... Alumina-Boria whisker 12 ... Distilled water 14 ... Propeller 16 ... Weight 18 ... Case 20 ... Molded body 22 ... High pressure casting device 24 ... Mold 26 ... Al alloy melt 28 ... Plunger 30 ... Knockout pin

Claims (1)

Claims: 1. Alumina-boria whiskers are used as a reinforcing material,
Using an Al alloy containing Mg as a matrix,
Alumina-Boria whisker reinforced Al matrix composite material, characterized in that the alloy contains 0.03 to 0.8 wt% B.