Rapid sintering of ultra-fine WC-10 wt% Co by high-frequency induction heating

High-frequency induction-heated sintering (HFIHS) is utilized to consolidate ultra-fine grain WC-10 wt% Co. Densification to near theoretical density in a relatively short time can be accomplished with insignificant change in grain size. WC-10 wt.% Co with a relative density of up to 99.5% was produced within 1 min with the simultaneous application of 60 MPa pressure. The average grain size of the densified material was about 260 nm and the mean free path in the cemented carbide was about 11 nm. The sintered material had fracture toughness and hardness values of 13 MPa.m1/2 and 1886 kg/mm2, respectively. The hardness is comparable to literature values but the fracture toughness is about two times higher. These results are interpreted in terms of current effects on sintering and mass transport. Higher heating rates result in higher density with smaller WC grain size, and higher current-induced solubility of WC in Co is proposed as an explanation for the high fracture toughness. C 2005 Springer Science + Business Media, Inc.