Influence of annealing on the mechanical properties of compocast Al(Mg)-Al₂O₃ particulate composite

Abstract

The annealing of cast Al(Mg)-Al₂O₃ particulate composite at temperatures of 673, 723 and 773 K for varying periods of time from 1–5 h resulted in reduction of strength and hardness similar to that occurring in cast Al-Mg alloy, due to homogenization. However, the ductility of the composite increased on annealing, contrary to that observed in cast Al-Mg alloy, presumably because the solution of the eutectic in the composite causes magnesium diffusion to the alumina particles resulting in further reaction to form magnesium aluminate and does not increase the magnesium level of its primary phase, as occurs in Al-Mg alloy.