Influence of ZrB2/SiC Hybrid Particles on Microstructure and Creep Resistance of AZ31Magnesium Alloy Matrix Composite

Magnesium alloys have been attractive to engineers due to their high strength-to-weight ratio, leading to their widespread use in recent years. However, their poor creep resistance, particularly at high temperatures, has limited their applications. Reinforcing the magnesium matrix with ceramic particles could significantly improve creep properties. In this research, ZrB2 and SiC microparticles were separately milled for 6 hours at 350 rpm under an argon atmosphere, and powders were mixed and milled for 2 hours at the same condition to achieve a homogeneous hybrid powder. The hybrid particles were added to the AZ31 magnesium alloy in various amounts via the stir-casting method, to produce hybridcomposites. The microstructure of specimens has been characterized using optical microscopy (OM), scanning electron microscopy (SEM), X-ray analysis (XRD), and energy-dispersive X-ray spectroscopy (EDX). The results indicated that the AZ31/1.5vol% ZrB2-0.5vol% SiC hybridcomposite possessed the finest grains with uniform distribution of reinforcements and the intermetallic β-Mg17Al12 phase. Hardness and creep tests were performed to evaluate the creep resistance of the hybridcomposites. While AZ31/2vol% SiC showed the highest hardness, the AZ31/1.5vol% ZrB2-0.5vol% SiC hybridcomposite demonstrated the best creep behavior.