Fabrication process for high temperature aluminum alloys by squeeze

Abstract

A method for fabricating articles of high-temperature aluminum alloys having a compressional strength of at least 20 kg/mm.sup.2 at temperatures of 300.degree. C. or greater, is disclosed. The method comprises the steps of: (a) forming a porous preform from particles of a first aluminum alloy via cold-pressing, the preform having the shape and dimension of the aluminum alloy article to be fabricated; (b) squeeze-casting a molten second aluminum alloy into void spaces of the porous preform to form an aluminum composite containing the first aluminum alloy, which serves as a reinforcement phase, dispersed in the second aluminum alloy, which serves as a matrix phase; (c) wherein the molten second aluminum alloy is cast at such temperatures so as to cause a surface of the first aluminum alloy particles to melt and thereby form a strong bonding with the second aluminum alloy. The first aluminum alloy particles are formed by melt-spinning, followed by rapid solidification and precipitation, of a composition of the first aluminum alloy to form a thin ribbon, then pulverizing the thin ribbon into particles. Unlike the prior art processes, which fabricate high-temperature aluminum alloys only in essentially two-dimensional articles, the method disclosed herein allows the capability of near net shaping, i.e., it can fabricate high-temperature aluminum alloy articles of essentially any intended shapes. The present process allows selective reinforcement of the fabricated articles to be achieved at strategically important locations, so as to expand the range of engineering applications of the fabricated articles without incurring substantially increased manufacturing cost.