Fabrication and Tensile properies of SiCp/AZ91 Mg composites by hot extrusion

초록

the tensile properties and microstructural evolution of hot extruded SiCp/AZ91 Mg matrix composites have been investigated as functions of extrusion parameters and SiC praticulate size. Also the effect of SiC praticulates on. the grain size of matrix in the composites was studied. the AZ91 Mg alloy powders prepared by wet attrition milling from Mg mechined chips were hot-pressed with and without SiC particulates, hot-extruded and then solution-treated. the microstructural observation revealed that both the composites and Mg alloy have equiaxed grains due to the dynamic recrystallization during hot extrusion. The tensile strength of the both alloys increased with increasing extrusion ratio, and the strength of the composites were higher than that of the Mg alloy without reinforecement. It was found that the tensile strength of the both materials decreased after solution-treatment; the decrease in tensile strength of the composites was considerably smaller than that of the Mg alloy. The grain growth of the matrix in the matrix in the composites was inhibited by the introduction of the SiC particulates, resulting in the improvement in the yield strength of the composites. pressed