STRUCTURE AND PROPERTIES OF NANOPHASE WC CO/VC/TAC HARDMETAL/

A new approach to produce nanophase WC/Co/VC/TaC powder was developed by thermochemical processing method for improving the mechanical prope rties. To overcome coarsening and abnormal grain growth of the WC part icles for nanophase WC/Co during the sintering, VC/TaC, VC, and TaC ar e used as the grain growth inhibitors by mechanical and chemical proce ss. Nanophase WC/Co eloped VC and VC/TaC by mechanical mixing was show n nanoscale microstructure, but exaggerated local grain growth was obs erved due to non-uniform distribution of grain growth inhibitors Nanop hase WC/Co/VC/TaC synthesized by chemical process was shown ultrafine microstructure without local grain growth microstructure and mechanica l properties of nanophase WC/Co/VC/TaC are compared with those of comm ercial submicron WC/Co/VC/TaC. (C) 1997 Acta Metallurgica Inc.