The effect of die shape on the hot extrudability and mechanical properties of 6061 Al/Al2O3 composites

Metal matrix composites (MMCs) fabricated by the compocasting process show a homogeneous distribution of the reinforcing fiber in the matrix. Microstructural observation of hot extruded MMCs reveals that as the extrusion ratio increases, the fiber alignment becomes improved, but fiber fracture occurs more severely. The mechanical properties of hot extruded MMCs are better than those of the matrix metal, with the exception of the elongation at failure, and are not influenced significantly by the extrusion temperature. The tensile strength and hardness of MMCs are improved to a greater degree by hot extrusion using a constant-strain-rate die. Also, there exists a critical extrusion ratio that gives maximum strength, which is 5.44 in this study. Additionally, fractograph of the tensile specimen of extruded MMC indicates the ductile fracture behavior of the matrix.