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Based on the interaction of solid and liquid phases in metallic systems, the paper deals with the properties of grain boundary propagation (migration) in solid-state alloys. Using the effect of surface solid-state dispersion enables to obtain composite materials and brazed joints with a required set of physical and mechanical properties. For the first time, the authors investigate the features of boundary migration in type II systems, in which, in accordance with the thermodynamic criterion σss< 2 σSL, the grain-boundary propagation is not basically allowed.

The phenomenological model of laser joining at so called boundary kitetic is developed. The criteria of microjoints strength is suggested. As a result of kinetics of computer simulation of soldered joints forming, practical investigations of soldering modes influence at the joints strength and analysis of micro section metallographic specimens fulfilled with the aid of electronic microscope, the possibility of two-three fold enhancement of soldered joints strength in comparison with manual soldering. Technological process and automated equipment are developed for laser soldering of electronic components with planar leads at the printed circuit boards.