Arsenyuk V. Principles of formation of joints in dissimilar metals made by different pressure welding methods

It has been established for the first time that the rate of deformation is the main factor that determines peculiarities of structure and changes in the deformation mechanisms. It has been found that continuous layers of intermetallics are formed over the contract area at low deformation rates (vacuum diffusion bonding, friction welding). Deformation at a high rate (vacuum percussion welding, magnetic pulse welding, explosion welding) is accompanied by formation of dispersed phase precipitates (measuring from nano- to several micrometers). It is shown that the depth of the zone of localization of plastic strain depends upon the deformation rate and amounts to 25-200 m, the extent of localization varying from about 40 to 1000 %. New technical approach has been developed to analytical evaluation of strength and ductile properties of the welding zone, allowing for structural factors. A new approach to evaluation of weldability of dissimilar metals has been offered. Recommendations have been worked out. Optimal conditions and techniques have been identified for joining various combinations of dissimilar metals by different pressure welding methods, which are commercially applied for the manufacture of components and parts for industrial plants and systems. Applicability of different pressure welding methods for joining dissimilar hard-to-weld materials has been estimated, thus allowing selection of an optimal welding method.