Mechanical properties of binderless tungsten carbide enhanced via the addition of ZrO2-20 wt% Al2O3 composite powder and graphene nanosheets

Abstract

As an alternative to conventional tungsten carbide materials, binerless tungsten carbide (BTC) can be used in a variety of applications, such as high-speed cutting tools, rock drilling and extraction, and wear-resistant components. The absence of the metallic bonding phases solves the problems of oxidative corrosion and softening of the material during high-speed cutting process. However, the fabrication of high strength and toughness BTC ceramics remains a huge challenge. In this paper, ZrO2-20 wt% Al2O3 composite powder and graphene nanoplatelets (GNPs) were used as the reinforced phases to fabricate high performance BTC ceramics. The influence of GNPs contents on the densification, microstructure and mechanical properties of oscillatory pressure sintered BTC ceramics with 8 wt% composite powder was evaluated. The synergistic effect of ZrO2-20 wt% Al2O3 composite powder and GNPs exerted a critical role on the densification process and microstructural evolution. The produced BTC ceramics had the densest microstructure and optimal mechanical characteristics when the GNPs content reached up to 0.2 wt%; the flexural strength, Vickers hardness, fracture toughness and relative density were up to 1480 MPa, 23.72 GPa, 8.68 MPa·m1/2 and 99.8%, respectively.