An analytical model of the development and growth of embryos in a polycrystalline material during a phase transition at the intergranular slope boundary is proposed. The model assumes the presence of faces that are oriented crystallographically parallel to the forming boundary and are characterized by reduced surface energy. In this case, the faces refer to the densely packed plane of the lattice of matching nodes. The results obtained in the work on the evaluation of the parameters of the formed facets and the total testing time are confirmed by generalized experimental data.

Keywords: phase transitions, defects, microstructure, facets, boundary geometry, specific surface energy

The results of the development of asymptotic expressions for the calculation of the background of internal friction at the boundaries of the General type for the limiting cases of frequency dependence are presented. Mathematical expressions are obtained on the basis of consideration of models of the border containing periodically located steps of alternating signs and the intercrystalline border of the general type consisting of parallel plane segments of the set width separated by alternating steps of identical height and cylindrical pores.

Keywords: model, boundary, internal friction background, relaxation, temperature-frequency dependence, slip rate

The results of the analysis of various models of structural defects formed at grain boundaries in metals are presented. It is shown that the resulting boundary defects should be taken into account when determining the tensile stresses on the lines of their junction. The development of ideas about the structure of defects contributes to a better understanding of the mechanism of their occurrence in crystals and a better definition of changing chemical and physical properties at the atomic level.

Keywords: defects, grain boundary dislocations, facets, microplasticity, plastic deformation, boundary geometry