FABRICATION AND CHARACTERIZATION OF SiC WHISKER/PARTICLE-REINFORCED MAGNESIUM COMPISTES FABRICATED BY SPARK PLASMA SINTERING

In this study, SiC whisker/ particle-reinforced magnesium composites have been prepared by spark plasma sintering (SPS) processes. SPS processing resulted to formation of a fully dense composite. The bending strength of these three samples (Mg-SiCw0.5%vol, Mg-SiCw0.5%SiCp1%vol, Mg-SiCp3%vol) exceeds that of oxidized pure magnesium. However, the mechanical characterization results revealed that except for Mg-SiCp3%vol, the sample added with SiCw shows lower bending strength than pure magnesium. The SEM images and EDX results show that the mechanical performance of the composite depends on the dispersing state of SiCw and the void defects inside the composite which were caused by the oxidation phenomenon. Mixing Mg powder with an additive element powder (1 at.% Sn, 1 at.% Bi, 0.25 at.% Al) that is capable of eutectic reaction with magnesium or that has a lower melting point than magnesium has been tried to solve the problem above. Based on all the above results, to further enhance the performance of the material, rolling treatments have been conducted to crush cracks that may remain inside the composite