In-situ elongated β-Si3N4 grains toughened WC composites prepared by one/two-step spark plasma sintering

Abstract

The WC–Si3N4 composites toughened by in-situ elongated β-Si3N4 grains were prepared by spark plasma sintering. By exploiting the difference in kinetics between WC grain-growth and β-Si3N4 grain-growth through sintering at an elaborate temperature or two-step sintering, composites with microstructure of in-situ elongated β-Si3N4 grains were grown sufficiently in the fine-grained WC matrix without fast-grain-growth being obtained. The relation of the microstructure and mechanical properties of the composites, as well as the toughening mechanisms, are investigated. Comparing with the fracture toughness of 6.69MPam1/2 for the pure WC, that of the obtained WC–Si3N4 specimen reaches 10.94MPam1/2.