The book summarizes the research conducted by the authors of crack resistance of materials from some types of refractory compounds depending on the structure formed by powder metallurgy methods. The results are presented and discussed against the background of a review of work on methods for certifying the fracture viscosity of refractory compounds within the framework of fracture mechanics and its relationship with the structural factor. Materials with porous and dense structure in homogeneous and heterogeneous performance are considered. The possibility of increasing the crack resistance of materials from powders of refractory compounds is shown while reducing the localization of deformation and limiting the length of the volume interaction of phases. The analysis of fracture resistance is performed with the application of criteria characterizing both the initiation of destruction and the kinetics of its development.