THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE PROCESS OF PLASTIC DEFORMATION OF SINTERED COMPOSITE MATERIALS. I. ANALYSIS OF THE CONDITIONS OF SIMULTANEOUS DEFORMATION OF THE DIFFERENT PHASES OF A COMPOSITE MATERIAL

The plasticity function of a composite material (like that of a porous powder medium) depends on the first invariant of the stress tensor, and the intensity of this dependence, assessed by the internal friction angle, is determined by the magnitude of the difference in strength properties between the components of the composite material, the area of the property discontinuity surfaces in unit volume of the composite, and the relative orientation of the property discontinuity and slip surfaces. The existence of a relationship between the shear strength of a composite material and the field of compressive stress acting in it makes it possible to employ changing the latter as a means of controlling the state of the “hard” phase during deformations and, in particular, ensuring simultaneous deformation of the dissimilar phases, which always takes place when the level of tangential stress in a composite attains the ultimate shear strength of the material of its “hard” phase.