Microstructure, mechanical properties and machining performance of hot-pressed Al₂O₃ - ZrO₂ - TiC composites

The effect of adding nanocrystalline ZrO₂ and submicron TiC to ultrafine Al₂O₃ on mechanical properties and the microstructure of the composites developed by hot pressing was investigated. It was shown that by means of hot pressing in an argon atmosphere at a sintering temperature of 1500 °C one can obtain the composites Al₂O₃ - ZrO₂ - TiC with a fine structure and minimal porosity. It has been shown that in material a multi-scale hierarchical structure is formed, which possesses high physical and mechanical properties: the hardness and fracture toughness was 21.5 GPa and 5.2 MPa*m^1/2 respectively, the modulus of elasticity was 500 GPa and bending strength was 390 MPa. Tests on composites' cutting properties were carried out on interrupted cutting of hardened steel. All samples had wear of the cutting edge in the form of chips of the grain rear working surface of the tool, but the cutting tool which was made by Al₂O₃ - 10% ZrO₂ - 10% TiC had a minimum width of wear. (paper)