JPH0364578B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a composite material containing potassium titanate whiskers as a reinforcing material in aluminum and its alloys.

[Conventional technology]

Silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ) are well known as reinforcing materials used in fiber reinforced metal materials (FRM) having a matrix of metals such as aluminum or alloys.

However, SiC and Si ₃ N ₄ are expensive and are not suitable for inexpensive fiber-reinforced materials. On the other hand, potassium titanate whisker is a fiber that is inexpensive and has almost the same high strength and high elasticity as SiC and Si ₃ N ₄ .

One of the manufacturing methods for these fiber-reinforced composite materials is to create a preform from reinforcing fibers by suction, fill this into a mold, and then pressurize molten metal to penetrate into the preform and solidify to create a composite. There is a molten metal casting method. In this method, the volume content Vf of reinforcing fibers is changed by changing the bulk density of the preform. SiC
In composite materials reinforced with aluminum, Al powder is mixed with
A method of compounding mixed powder by hot extrusion processing is also known.

[Problem that the invention seeks to solve]

The disadvantages of these conventional fiber-reinforced composite materials are that secondary processing such as machining is difficult, and that they have low ductility and toughness. In other words, in the molten metal casting method, when the bulk density is low, the preform is crushed when the molten metal penetrates the preform under high pressure, resulting in uneven Vf of reinforcing fibers and composite materials with extremely high Vf. can be created. When such materials are heat-treated to improve their mechanical properties, cracks may occur in the composite material, resulting in a decrease in strength and impairing the reliability of the material.

[Means for solving problems]

Therefore, the present invention aims to improve strength and workability by making the crystal grains of the matrix finer and reducing the Vf of the reinforcing fibers. In other words, by using Al powder with a fine average particle size,
Uniform mixing with potassium titanate whiskers and Vf
We adopted a powder metallurgy method that allows arbitrary selection of

[Effect]

In the method according to the invention, an average particle size of 0.5
~20μm Al powder and average diameter 0.2~0.5μm, length 10
When ~20 μm potassium titanate whiskers are placed in a solvent such as alcohol and subjected to ultrasonic vibration for a long period of time, the tangled whiskers will form as shown in Figure 1.
Al powder enters, allowing uniform mixing of Al and reinforcing fibers.

〔Example〕

Examples of the present invention will be described below.

Al mixed in appropriate amount to achieve the desired Vf
Put the alloy powder and potassium titanate whiskers in a solvent such as alcohol (approximately 50 g per portion) and apply ultrasonic vibration using an ultrasonic cleaner or the like for 5 to 10 hours or more.
Disentangle the Al alloy powder and whiskers and uniformly disperse the Al alloy powder into the whiskers. From this mixed powder, in vacuum or air,
Splash the solvent at a temperature of about 100℃. This mixed powder is packed into an Al tube and pressure-molded at room temperature under a pressure of about 2 kgf/mm ² . This is pressure sintered by hot extrusion processing (Fig. 2) or hot press,
An Al/potassium titanate whisker composite is produced.

〔Effect of the invention〕

Since the Al/potassium titanate whisker composite material according to the present invention uses powder metallurgy, the Vf of the whisker is
can be changed arbitrarily. Figure 3 shows Vf=25
% composite material, with a structure in which whiskers are uniformly dispersed in Al. FIG. 4 is the high temperature tensile strength of the composite material according to the invention.

When Vf=25% or more, 40Kgf/mm ² at room temperature,
A strength of about 18 Kgf/mm ² or more was achieved at 300°C.

[Brief explanation of drawings]

Figure 1 is a photograph of the particle structure of a mixture of Al alloy powder and potassium titanate whiskers. Second
The figure shows a method in which this mixed powder is packed into an Al tube and sintered under pressure using hot tube extrusion. Figure 3 is
This is a photograph of the metal structure of a composite material with Vf = 25%.
Figure 4 shows the high temperature strength of the composite material. 1: Potassium titanate whisker, 2: Aluminum alloy, 3: Aluminum tube, 4: Dice,
5: Container, 6: Punch.

Claims (1)

[Claims] 1. Put aluminum alloy powder with an average particle size of 0.5 to 20 μm and potassium titanate whiskers in a solvent such as alcohol, mix them uniformly while applying vibrations using ultrasonic waves, etc., remove the solvent by evaporation, and then compact the powder. An aluminum alloy-potassium titanate whisker composite material produced by heating and sintering by hot extrusion or hot pressing.