Mechanical properties of SiC p/Al 2O 3 ceramic matrix composites prepared by directed oxidation of an aluminum alloy

Abstract

Silicon carbide particulate reinforced alumina matrix composites were fabricated using DIrected Metal OXidation (DIMOX) process. Continuous oxidation of an Al–Si–Mg–Zn alloy with appropriate dopants along with a preform of silicon carbide has led to the formation of alumina matrix surrounding silicon carbide particulates. SiC p /Al 2O 3 ceramic matrix composites fabricated by the DIMOX process, possess enhanced mechanical properties such as flexural strength, fracture toughness and wear resistance, all at an affordable cost of fabrication. SiC p /Al 2O 3 matrix composites were investigated for mechanical properties such as flexural strength, fracture toughness and hardness; the composite specimens were evaluated using standard procedures recommended by the ASTM. The SiC p /Al 2O 3 ceramic matrix composites with SiC volume fractions from 0.35 to 0.43 were found to possess average bend strength in range 158–230 MPa and fracture toughness was found to be in range of 5.61–4.01 MPa√m. The specimen fractured under three-point loading as observed under scanning electron microscope was found to fail in brittle manner being the dominant mode. Further the composites were found to possess lower levels of porosity, among those prepared by DIMOX process.