Cause and Catastrophe of Strengthening Mechanisms in 6061/Al2O3 Composites Prepared by Stir Casting Process and Validation Using FEA

The present research has been focused to anticipate all these effects in 6061/Al2O3 metal matrix composites. It was found that the tensile strength and stiffness increase with increasing volume fraction of Al2O3 particulates. The tensile strength and stiffness were decreased with increased size of particulates. After heat treatment to the T4 condition, most of the coarse intermetallic phases such as (Al2Cu, Mg2Si) are dissolved to form Al5Cu2Mg8Si6 or Al4CuMg5Si4 compound. A clustering of particulates was observed in the composites having very small particles. Formation of Mg2Si precipitates were also noticed at the matrix/particle interface. The interface between particle and matrix was assumed to be Mg2Si for the finite element analysis. The proposed formulae by the author for the tensile strength and elastic modulus could predict them very close to the experimental values of 6061/Al2O3 composites.