CAST-ALUMINA METAL MATRIX COMPOSITES

摘要

This composite consists of an aluminum-alloy matrix containing by volume percent, 0.4 to 8.8 alumina, 1 to 4.4 carbon or graphite and 0.5 to 20 nickel-be aring aluminide. The alumina particles have an average size between 3 and 250 .mu.m an d the carbon and graphite particles have an average size between 10 and 250 .mu.m. The composite is cast by stirring alumina and carbon or graphite contained in a molt en aluminum or aluminum-base alloy to form a molten mixture. The molten mixture is cast directly from a temperature above the liquidus of the matrix alloy. While solidi fying, carbon or graphite particles delay or hinder the settling of alumina to create a more uniform composite structure. The resulting composite structure contains an alumi num-base alloy, alumina, carbon or graphite and nickel-bearing aluminide dispersoids.