Microwave synthesis and characterization of magnesium based composites containing nanosized SiC and hybrid (SiC +Al2O3) reinforcements

Abstract

In the present study, monolithic magnesium, nanosized SiC reinforced magnesium and nanosized hybrid (SiC+Al2O3) reinforced magnesium materials have been synthesized by using powder metallurgy route involving microwave sintering followed by hot extrusion. The results show that the monolithic and the reinforced magnesium materials have minimal porosity and the reinforced magnesium materials have fairly well distributed nanosized SiC and SiC + Al2O3 particles in the matrix. The thermo-mechanical property measured in terms of coefficient of thermal expansion of the reinforced magnesium shows dimensionally more stable magnesium as compared to monolithic magnesium. The hardness 0.2% YS and UTS were found to improve significantly after addition of nanosized SiC and nanosized hybrid SiC + Al2O3 particles to the magnesium, However, ductility measured in terms of failure strain was found to be marginally reduced. Fractography results showed the presence of brittle failure mode with cleavage steps on the fractured surface of the magnesium matrix. Copyright © 2007 by ASME.