[SIS9] Hard Materials

[16F-SIS9-03] Liquid Phase Migration and Shape Distortion of WC-Co Cemented Carbides during Sintering

*T. Saito¹, Y. Fukuichi¹, T. Kajiwara¹, H. Endo¹, S. Terasaka^{2, 3} (1.Kyoritsu Gokin Co., Ltd., Japan, 2.Tohoku University, Japan, 3.Japan Fine Ceramics Center, Japan)

Keywords:WC-Co, cemented carbides, liquid phase sintering, shape distortion, liquid phase migration

WC-Co cemented carbides are manufactured using powder metallurgy and liquid phase sintering. In the industrial products of cemented carbides, the shape quality of the cemented carbides which is to fabricate them within dimensional tolerances is as important as the material property quality. However, the shape of cemented carbides after sintering is often distorted, which cannot be explained by non-uniformity of compact density or the effect of gravity. In this study, ground WC-Co cemented carbide round bars were used to accurately understand the phenomenon. These round bars were reheated at 1673 K and then examined for changes in diameter and Co content distribution in the longitudinal direction under different cooling conditions. By analyzing these results, the shape distortion of cemented carbide during sintering was investigated in relation to the liquid phase migration that occurs during cooling from the sintering temperature. The mechanism of liquid phase migration during cooling was also discussed.