EFFECTS OF Ni CONTENT ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ALUMINA/SILICON CARBIDE TOOL COMPOSITES

Alumina-based ceramic composites are widely used for cutting tools owing to their high strength and oxidation resistance. However, their brittle nature and low toughness adversely affect their use and performance. In this study, alumina/silicon carbide (Al2O3/SiC) composites with different mass fractions of Ni (5 %, 10 %, 15 %, and 20 %) were prepared via vacuum hot-press sintering to optimise their strength and toughness. The structural and mechanical properties of the composites were characterised using various techniques. The hardness and bending strength of the Ni-doped Al2O3/SiC composites increased with the Ni content up to 10 % and decreased with a further increase in the Ni content. The maximum values of the hardness, bending strength, and fracture toughness were 7.19 GPa, 871.25 MPa, and 7.90 MPa·m1/2, respectively. Thus, the addition of Ni improved the mechanical properties overall and provided a toughening effect.