The Role of Heat Treatment on Characteristics of Mg-Al-Sr Reinforced Nano-SiC Composite

Abstract

The effect of heat treatment on microstructure and mechanical properties of SiC/Mg-Al-Sr alloy matrix composite was investigated. The heat treatment involved annealing at 425, 375, and 325°C for 4 hours, water quenching then ageing at room temperature for 48 hours. The heat treatment process caused dissolution ofs Mg2Si precipitated and decomposition of nano-SiC particles. The composites with 0.15 Vf-% nano-SiC which was treated at 425°C has reached the optimum hardness due to precipitate of the intermetallic phase. Besides, the hardness of the treated composites still has good ductility. The fracture surface of the composite consisted of numerous dimples as a result of micro voids nucleated at the interface between the matrix and SiC particles and second-phase particles as well. The fracture of heat treated composite was similar to microvoids which were nucleated mainly on nano-SiC particles as obtained during fractography analysis.