Evaluation method of thermal shock resistance of cermets

Tungsten (W) used in cemented carbide tools is one of rare metals. As there is some concern about securing its stable supply, the development of W substituted materials is required. For the development of the substituted materials for tungsten carbide (WC)-based cemented carbide, new titanium carbonitride (Ti(C,N))-based cermets and new coating technology have been studied for applying them to cutting tools and wear-resistant tools. Thermal shock resistance is an important property of tool materials used in severer environment. However, evaluation method of thermal shock resistance has not been established for cermets. In order to develop a method to evaluate the thermal shock resistance, a constant heat flux method was studied by FEM calculation. Furthermore, irradiation experiments using a high power laser were conducted; laser beam was irradiated on the surface of thin specimens. The experimental results showed that a critical laser power for crack initiation can be used practically to evaluate the thermal shock resistance of cermets.