Microstructure and mechanical properties of a high volume fraction SiC particle reinforced AlCu4MgAg squeeze casting

The microstructure and mechanical properties of a high volume fraction SiC particle reinforced AlCu4MgAg alloy produced by squeeze pressurised infiltr ation of dense packed particle preforms were characterised. It was found th at the addition of 60 vol.% 12 mu m SiC particles eliminates the processing related intrinsic macrosegregation of the matrix alloy, induces coarse pre cipitates in as-cast matrix, but does not impede matrix grain growth. The S iC-Al interfacial chemical reaction is suppressed to a limited extent. In T 6 condition, the interfacial intermetallics are largely dissolved and the m atrix is decorated with fine and dense precipitates of theta' and Q phases. The addition of SiC particles accelerates the age-hardening response of th e matrix alloy. Mechanically, the stiffness, hardness, flexural strength, f atigue strength and abrasive wear resistance are substantially improved, to gether with significantly reduced fracture toughness and ductility in compa rison with the matrix alloy. (C) 1999 Elsevier Science S.A. All rights rese rved.