Abstract
WC-βt-Ti(C, N)-Co alloys have different microstructures near surface due to sintering atmosphere. In order to evaluate the characteristics of these alloys with sintered surface, the effects of Ar and N2 sintering atmosphere on the hardness near surface and turning performance of these alloys were investigated. The obtained results were as follows; (1) The thickness of extreme surface layer without βt was slightly larger in Ar than N2 sintering atmosphere. It was mostly consistent with the area proportion of WC phase. Moreover, the microstructure change of the alloy under Ar sintering atmosphere was rather remarkable judging from the result of EDS analysis. (2) The hardness near surface of the alloy was higher in Ar than N2 sintering atmosphere. It was considered to be mainly due to Co content near surface of the alloy. Consequently, (3) the alloy under Ar sintering atmosphere was superior in flank, nose and crater wear resistance as compared with the alloy under N2 sintering atmosphere. (4) The alloy under Ar sintering atmosphere showed better fracture resistance than the alloy under N2 sintering atmosphere.
