Fracture toughness of tungsten alloys

We have performed in the last few years theoretical as well as experimental studies to investigate fracture relevant phenomena of tungsten. A summary of the result will be presented in this paper. The theoretical studies are based on density function theory analyses of dislocation mobility and the effect of impurities on decohesion energy. The experimental studies are mainly focused on the variation of the fracture toughness as a function of: temperature, in the temperature interval between the temperature of liquid nitrogen and 800 C; the effect of processing conditions, degree of deformation and effect of recovery and recrystallization etc.; the influence of alloying elements; the orientation dependence of fracture toughness, special attention was devoted to the effect of texture, grain size and grain shape, in order to improve the understanding of the brittle fracture process of tungsten alloys. In addition micro mechanical experiments have been performed to study in more detail the cleavage crack propagation process.