Effect of magnesium on mechanical properties of Al2O3/AlZnMgCu metal matrix composites formed by squeeze casting

Al2O3/Al-Zn-Mg-Cu composites containing 2.0–3.0wt% Mg in the matrix alloy have been fabricated by squeeze casting. Light microscopy, scanning electron microscopy and image analysis were used to examine and analyze the details of the microstructure and the fracture surface. Tensile tests were used to evaluate the mechanical properties. The aging behavior of the composites was studied using differential scanning calorimetry (DSC) techniques and microhardness tests. The microhardness and ultimate tensile strength (UTS) of the composites increase with increasing Mg content. The maximum microhardness and UTS of the composites occur after aging for 24 h at 120 °C.