The three-layer composite AMg6–AD1–VT1-0, obtained by explosion welding, is widely used as transition elements in the creation of critical structures made of titanium and aluminum alloys. In welded joints of dissimilar metals, which are limited soluble in each other and form intermetallic compounds, mutual diffusion can occur at elevated temperatures, and when the concentration corresponding to the limit of solubility at a given temperature is reached, conditions are created for the nucleation and growth of intermetallic phases. When studying the effect of heat treatment on the properties of welded joints of such metals, it is necessary to take into account the structure, properties and features of the formation of intermetallic phases, as well as the factors that contribute to their appearance and intensive growth. The latter include hardening, obtained by the composite material after blasting and further technological operations, associated with pressure treatment, which accelerate the diffusion processes, due to fragmentation and development of the block structure.