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

Al2O3/AlZnMgCu composites containing 2.0 ∼ 3.0 wt.% 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 microstructure and the fracture surface. Tensile tests were utilized to evaluate the mechanical properties. The aging behavior of the composites was studied by using differential scanning calorimetry technique 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 at 120 °C aging for 24 h.