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