INTERFACE STRUCTURE AND MECHANICAL PROPERTIES OF POWDER METALLURGICAL 6061 ALUMINUM MATRIX COMPOSITES REINFORCED WITH VARIOUS KINDS OF OXIDE WHISKERS

Abstract

The compatibility of oxide whiskers with 6061Al alloy and the age hardening behavior of composites prepared from powder metallurgy were investigated. Interface reactants containing Mg were shown to be formed during hot pressing and hot extruding for every composite. The composites did not reveal age hardening behavior due to the depletion of Mg in the matrix at all. To keep whiskers from the interfacial reaction, electroless nickel plating onto whiskers was carried out. Although the composite with Ni plated whiskers revealed the age hardening, its hot workability was too poor to apply practical fabrication because of the formation of brittle intermetallic compound Al₃Ni in the matrix.