The simultaneous effect of extrusion ratio and solution heat treatment on the microstructure and tensile properties of extruded al-15%mg2si-1.0%gd composite

Abstract

The effect of extrusion ratios and solution heat treatment on microstructure and tensile properties of extruded Al-15%Mg2Si-1.0%Gd composite was investigated. The as-cast composite was hot extruded using three different dies and solution heat treated. After conducting heat treatment on extruded samples, microstructure alteration was examined using scanning electron microscope (SEM). Furthermore, mechanical properties of the composites were studied with tensile test. The results demonstrated that extruded and heat treated composite possesses higher strength and ductility compared to as-extruded composites. It was also found that the extrusion and heat treatment processes altered the morphology of primary Mg2Si particles as well as reduction in their size especially when the extrusion ratio increases. Fracture surface examination revealed a transition from ductile fracture in as-extruded samples to more ductile fracture in extruded and heat treated ones. This can be attributed to the change in size and morphology of primary Mg2Si particles as well as fragmentation of Gd intermetallic compounds.