Effects of size and oxidation treatment for SiC particles on the microstructures and mechanical properties of SiCp/Al composites prepared by powder metallurgy

SiC particles (SiC p ) reinforced Al matrix composites as the one of the most representative ones in the field of metal matrix composites , and many researches about the enhancement effect of SiC p size on mechanical properties of SiC p /Al composites have mainly focused on the comparison of micron-sized and nano-sized SiC p . In this paper, low-cost submicron-sized SiC p with rare attention was used as novel reinforcements, and the enhancement effect was compared with that of nano-sized SiC p . At the same time, a strategy of oxidation treatment for SiC p is developed in the field of powder metallurgy , and related work has been carried out. Raw submicron-sized SiC p (hereafter named SiC smp ) and raw nano-sized SiC p (hereafter named SiC np ) were calcined at 1100 °C. Then, SiC smp (raw and oxidized) and SiC np (raw and oxidized) were used as reinforcements to prepare Al matrix composites with different reinforcement content by powder metallurgy. The enhancement effect of raw SiC np is slightly better than that of raw SiC smp when the content is below 7 vol%. Although the agglomerations of oxidized SiC p were found owing to increased agglomeration tendency after oxidation treatment for SiC p , the tensile strength of composites were enhanced significantly, especially for SiC np /Al composites. Furthermore, the ductility of SiC smp /Al composites was also improved after calcining for SiC smp and thus excellent comprehensive mechanical properties were obtained.