Preparation and mechanical properties of SiCw-reinforced WC-10Ni3Al cemented carbide by microwave sintering

Abstract

SiCw-reinforced WC-10Ni3Al cemented carbide was prepared by microwave sintering method, and the effects of the sintering temperature and SiCw content on the microstructure and mechanical properties of WC-10Ni3Al cemented carbide were investigated; the promotion effect and strengthening mechanism of SiCw were then analysed. The experimental results showed that the relative density, hardness, flexural strength and fracture toughness of WC-10Ni3Al cemented carbide increased and then decreased with increasing SiCw addition and sintering temperature. When the sintering temperature was 1500 °C and the content of SiCw was 0.3 wt%, the sample reached the highest mechanical properties and had a relative density of 96.5%, hardness of 1570 HV, flexural strength of 1275 MPa and fracture toughness of 13.1 MPa mm1/2, which were 4.0%, 23.1%, 12.5% and 8.1% higher than those of the sample without SiCw, respectively. During microwave sintering of WC-Ni3Al, the addition of an appropriate SiCw content can increase the microwave absorption of the sample, and produce many micro-high-temperature regions within the sample, which can accelerate the generation of the Ni3Al liquid phase. This promotes liquid phase flow to fill pores and rearrange the WC grains, thereby improving density and mechanical properties of the sample. The strengthening mechanisms of SiCw on microwave sintered WC-Ni3Al consist of promoting densification enhancement, fine-grained strengthening, and solid solution strengthening of Ni3Al by Si atoms.