Fabrication and mechanical behavior of Al matrix composites reinforced with porous ceramic of in situ grown whisker framework

Abstract

Porous ceramics with a framework of aluminum borate whiskers (porous aluminum borate) were fabricated by in situ firing ceramic powder compacts, and incorporated within a Al alloy matrix by squeeze casting. The in situ technique of fabricating the porous aluminum borate is more cost-effective and safer for workers than traditional perform technique. The microstructures of the porous aluminum borate and the composites are isotropic and independent of the compacting and the casting direction. The Vickers hardness and the tensile strength of the Al alloy matrix composites increase with increasing volume fraction of porous aluminum borate from 20 to 30% or with decreasing diameter of aluminum borate whiskers from 1.2 to 0.3 μm. The tensile strengths of the composite are about 65 and 150% higher than those of unreinforced Al alloy at room temperature and 350 °C, respectively.