Fabrication and Mechanical Properties of WC Alloy Hard Materials by a Pulsed Current Activated Sintering Method

摘要

In this study, planetary ball milled WC-5 wt%Co powders were sintered using the pulsed current activated sintering (PCAS) process. With this process, fully densified hard materials were obtained in a shorter time than conventional processes such as a HP and HIP. The particle sizes of the planetary ball milled WC and Co were 0.114 mu m and 0.154 mu m, respectively. The PCAS process was performed at temperatures up to 1300 degrees C with 60 MPa and electric current for 13 min without any significant change in the grain size. The WC-5 wt% Co hard materials were fully densified with a relative density of up to 99.8%. The density of WC-5 wt% Co hard materials increased with increasing shrinkage ratio. In addition, the Co particles penetrated into the WC particles by dissolving and re-precipitation, and finally hard materials were completely densified. The average grain size of the WC-5 wt%Co was 0.25 gm, and the hardness and fracture toughness were 2,386 kg/mm(2) and 6.0 MPa.m(1/2), respectively. The mechanical properties of the WC-5 wt% Co hard materials were excellent because of grain refinement and densification.