This investigation is a continuation of these works. The proposed method of determination of Kic and Kid is applicable to alloys with a body-centered cubic lattice in the 0 5 T ! 0.2Tmelt temperature range. A clearly expressed temperature-rate relationship of yield strength is characteristic of alloys with a body-centered cubic lattice. In addition, at a certain temperature a sharp change in the energy, force, and deformation characteristics of such alloys occurs as the result of the presence in them of the ductile-to-brittle transformation.