Enhancing strength and ductility of Mg/SiC composites using recrystallization heat treatment

In the present study, magnesium composites with sub-micron size silicon carbide (SiC) particulate reinforcements were successfully synthesized using an innovative Disintegrated Melt Deposition technique followed by hot extrusion. The extruded materials were characterized for their microstructural, thermal and mechanical properties. Systematic investigations on the microstructure of the extruded samples revealed a fairly uniform distribution of SiC particulates with limited clustering. Good SiC/Mg interfacial integrity and limited porosity was observed for all the samples. The results of the properties characterization revealed that SiC in sub-micron length scale are more effective in lowering CTE, and enhancing hardness, 0.2% yield strength, and ultimate tensile strength when compared to SiC particulates in micron length scale. Subsequently, isothermal heat treatment at 150 °C for 5 h was carried out for the composite samples. The results of tensile testing revealed that the heat treated samples showed an improvement of 0.2% YS, UTS and ductility. Particular emphasis is placed in this study to investigate the effect of heat treatment at the recrystallization temperature on the tensile properties of magnesium.