Microstructure evaluations and mechanical properties of rheo-cast AZ80/Ca/Al2O3 nanocomposite after extrusion process

In current study, AZ80-0.5 wt%Ca-1.5 vol%Al2O3 magnesium matrix nanocomposite was fabricated by rheo-casting method. After T4 heat treatment, the nanocomposite was exposed to extrusion at 450 °C with extrusion ratio of 12:1. Microstructure and mechanical results showed fragmentation of eutectic phase to fine particles, dynamic precipitations and recrystallization (DRX), strong basal plane texture and the increase of yield strength, yield anisotropy and hardness of nanocomposite after extrusion process. Yield and ultimate tensile strengths of the extruded nanocomposite were increased by 87.8% and 126.4%, where in compression test, strengths of the nanocomposite were developed by 61.9% and 35.6%, respectively. Moreover, tensile elongation of the extruded nanocomposite was improved by 530%, while its compressive elongation was decreased by 31.5%. After compressive test, reorientation of lattice structure was occurred by twin formation and higher density of twins was observed in extruded nanocomposite than as-cast one.