Microstructure and mechanical properties of Mg/SiC and AZ80/SiC nano-composites fabricated through stir casting method

The present work deals with the microstructure and room temperature mechanical properties of pure magnesium and cast AZ80 nano-composites. Toward this end, different weight percent of SiC reinforcement nano-particles (1.5, 2.5 and 3.5) were added homogenously into the matrix employing stir casting method. It was found that the SiC nano-particles can reduce the grain size of magnesium matrices, significantly. The presence of nano-particles assisted in improving the hardness values. In addition, the tensile strength and the ductility values increased by increasing the SiC content. This was reasoned considering the occurrence of grain refinement, Orowan strengthening, coefficient thermal expansion mismatch of the matrix-particles, and the load bearing effect. However, there was an optimum SiC content beyond which the strength and formability of the materials were decreased. The latter was attributed to the agglomeration of SiC particles in the microstructure of the composites. In line to these findings, the compression tests results also indicated continuous improvement of ultimate compressive strength. The compressive stress-strain curves were also employed to study the work hardening behavior of the materials. (C) 2014 Elsevier B.V. All rights reserved.