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

Abstract

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· m1/2, 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 °C by using appropriate original powder particle size. The hardness is improved while maintaining high flexural strength and high fracture toughness.