A higher efficiency and a higher stability in machining processes are always required for cutting tools. Improvements of mechanical properties of hard materials, especially a plastic deformation resistance and a fracture resistance at high temperature, are desired for achieving such requirements. Our studies for understanding fundamental phenomenon of the hard materials have played important roles to enhance their mechanical properties for cutting tools.

Our previous work about a forming mechanism of open pore on sintered surface of Ti(C,N) based cermet figured out the origin and the growth mechanism of the open pore by microstructure observation and elemental analysis of the hard material samples sintered under various sintering conditions. Another work about mechanical properties and forming mechanism of plate-like triangular prismatic WC cemented carbide revealed that the triangular prismatic WC grains were preferably oriented along the pressing direction when tungsten (W) and carbon (C) powders were used as the starting materials. The cemented carbide exhibited higher plastic deformation resistance and fracture toughness at high temperature as compared to conventional cemented carbides prepared using a tungsten carbide (WC) powder as the starting material did.