The microstructure and deformation behavior of W-SiC composites via spark plasma sintering

Abstract

In this paper, 0.5 wt% SiC nano particles and pure tungsten powders were thoroughly mixed using ball milling, followed by sintering the mixture using Spark Plasma Sintering (SPS) to obtain the W-0.5SiC composite material block. Then, the effect of sintering temperature on the microstructure and mechanical properties of W-0.5SiC composite was investigated. It was found that the tungsten carbide (W2C) and silicon oxide (SiO2) phases formed at the grain boundaris during the sintering process. Besides, the grain size of the composite increased with the increasing sintering temperature. To better understanding the mechanism of the grain growth, parameter fitting was proceeded based on the well-known grain growth power law. The grain growth parameters pointed out that the grain growth of the W-0.5SiC composite during the SPS process was mainly controlled by the surface diffusion. The hardness of 1800 °C sintered W-0.5SiC composite reached 342.2 ± 4.3 HV, and the compressive strength reaches 1417 ± 137 MPa. The digital image correlation technique was used during the compressive test of 1800 °C sintered W-0.5SiC composite to investigate the deformation behavior. The result indicated that the cracks tended to form at the edge of the sample or near the surface. The extension direction was almost parallel to the loading direction and went throughout the entire sample in at most 0.2 s.