JPS60204851A - Silicon nitride whisker-aluminum type composite material - Google Patents

Abstract

PURPOSE:To obtain an Al-base material proof against a higher temp. and having higher strength and harness by adding silicon nitride whiskers as a reinforcing material to Al or an Al alloy. CONSTITUTION:Al or an Al alloy is blended with 5-50vol% silicon nitride whiskers by a wet or dry process with a known stirrer to obtain a starting material for a composite material. The starting material may be formed into a sheetlike shape with a doctor coater or into a rodlike or threadlike shape with an extruder. Al or Al alloy powder and said whiskers may be sprayed on a substrate with a flame or plasma spraying apparatus to form a thin plate, which is then stripped to obtain a thin plate contg. whiskers arranged two-dimentionally in metal with high adhesive strength. Pellets contg. whiskers dispersed in the same direction may be formed. The starting material is subjected to known hot rolling, cold pressing-sintering, infiltration or die casting to manufacture a composite material. Molten metal may be infiltrated into the starting material under pressure and solidified under high pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel aluminum-based metal silicon nitride whisker-reinforced composite material. Withstands higher temperatures than metal materials,
New materials with higher strength and hardness are required.

Among metal materials, aluminum has a melting point of 660℃
As is clear from its tensile strength of 2.70 5 to 1 OKg/as, it is a material that is widely used in aircraft, automobiles, architecture, and even chemical machinery.

Aluminum-based materials with particularly high strength and heat resistance are known, such as duralumin, super-super duralumin, Roex alloy, Y alloy, etc. Even super-super duralumin has a tensile strength of 50 and 8711 m1! , Y alloy also has a maximum operating temperature of 230°C, which is insufficient in strength, especially high-temperature strength.

The present invention improves not only cold strength but also high temperature strength by using silicon nitride whiskers as reinforcing fibers, and can be applied to conventional working methods such as casting and cold/hot forging.

The materials used in the present invention are metallic aluminum or aluminum alloy as the base material, and the silicon nitride whiskers used as the reinforcing material are the
83095, Sho 57-55196, which has a diameter of 1 to 2 μm and a length of 100 to 300 μm, and preferably has αSi3N of 99% or more, or a product equivalent thereto.

First, there are three known methods for preparing a composite raw material by blending silicon nitride whiskers with metal aluminum or an aluminum alloy as a base material.

(1) Wet or dry method using a mixing stirrer (2) Sheet form using a doctor coater (3) Rod form or thread form using an extruder Furthermore, the present invention additionally provides the following method (4) as a composite raw material. It is something.

That is, (4) aluminum and aluminum alloy powder and silicon nitride whiskers are made into a thin plate on a substrate such as stainless steel using flame spraying or plasma spraying equipment in a predetermined ratio, and this is peeled off to use as a raw material for a whisker-reinforced composite material. It is something.

The raw material prepared by (1) is suitable for composite materials in which whiskers are arranged isodirectionally, (2) and (4) are reinforced by a two-dimensional arrangement of whiskers, and (3) is reinforced by a unidirectional whisker arrangement. , can be selected when the direction of reinforcement is taken into consideration.

In particular, (4) allows good adhesion between the metal and the whiskers in advance, and also makes it possible to produce pellets that are isodirectionally dispersed with the two-dimensionally arranged thin plates as described above.

Next, there are the following four known methods for manufacturing a composite material using aluminum, an aluminum alloy, and silicon nitride whiskers, and using already mixed raw materials for the composite material.

■High temperature rolling ■Cold pressing-sintering ■Melt infiltration method ■Die casting Furthermore, the present invention additionally provides the following method (2).

■High-pressure solidification casting method, which is a method of infiltrating molten metal under pressure and solidifying it under high pressure.

According to the manufacturing method described in Example text (■), 17 parts by volume of silicon nitride whiskers were mixed with pure aluminum, and the mixture was heated at 700°C and weighed 500 kg.
As shown in Table 1, the tensile strength reached 15 g/mva, three times that of the original metal, and the wear resistance was three times that of the original metal. It became clear that it could be reached.

Table 1 patent applicant

Claims (1)

[Claims] A whisker-reinforced high-strength composite material having a composition of silicon nitride whiskers at a volume ratio of 5% to 50% to aluminum and aluminum alloys.