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

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 6.69 MPa m1/2 for the pure WC, that of the obtained WC–Si3N4 specimen reaches 10.94 MPa m1/2.