A New WC-Based Tool Material with High Comprehensive Mechanical Properties

In this article, a new WC- Al2O3 composite tool material is successfully fabricated by vacuum hot-pressed sintering process with high hardness and flexural strength as well as fracture toughness, which solved the problem of mutual restriction between hardness and toughness of existing WC-Co composite tool materials. By adding Al2O3, the hardness of WC-based cemented carbide tool is significantly improved, the flexural strength and fracture toughness are also improved. The fracture mode of WC-Al2O3 composites is transgranular/intergranular mixed fracture mode due to the addition of Al2O3, and more fracture energy is consumed during crack propagation, thus improving the fracture toughness of WC- Al2O3 composites. When Al2O3 content is 5 wt%, the comprehensive mechanical properties of WC-based cemented carbide is the best, with a fracture toughness of 12.3 +/- 1.0 MPa center dot m(1/2), a flexural strength of 1385 +/- 65 MPa, and Vickers hardness of 22.8 +/- 1.6 GPa. In this article, the sintering temperature and holding time are optimized. The WC- Al2O3 composite tool materials with excellent comprehensive mechanical properties are fabricated at low sintering temperature of 1450 degrees C by using appropriate original powder particle size. The hardness is improved while maintaining high flexural strength and high fracture toughness.