Effect of oxidation of SiC particles on mechanical properties and wear behavior of SiCp/Al6061 composites

In this paper, oxidized-silicon carbide particle/aluminum 6061 (oxidized-SiCp/Al6061) composites were fabricated using a spark plasma sintering technique. The microstructure, mechanical properties, and wear behavior of oxidized-SiCp/Al6061 composites were investigated. The results revealed an improvement in interfacial bond strength between Al6061 and oxidized SiCp due to the formation of an MgAl2O4 continuous phase and suppression of brittle Al4C3 formation at the interfacial layer. Hardness (∼145 HV), ultimate tensile strength (∼226 MPa), and elongation (10.8%) were enhanced by 75%, 26%, and 32%, respectively, for the composite containing 1400°C-oxidized SiCp, compared with those reinforced with as-received SiCp. The friction coefficient and specific wear rate of oxidized-SiCp/Al6061 composites were reduced by 7% and 17%, respectively; this is attributable to the improved hardness and strength of the composite and the transition of wear mechanisms from a combination of adhesive and fatigue wear to abrasive wear. Quantitative correlations among yield strength, ultimate tensile strength, and interfacial bond strength in SiCp/Al6061 composites were analyzed for the first time.