EVOLUTION OF SELF-ORGANIZATION PROCESS UNDER EXPLOSIVE WELDING: MICROSTRUCTURES AND INTERFACES
The processes under study that take place inside weld seams follow the principle of self-organization of open systems, according to which, a system selects such dissipative channels that would ‘spend' applied external energy in a fastest way. The system is self-organized by means of a variety of mechanisms: formation of cusps, vortexes, local melted zones, quasi-wavy and intermittent surfaces. These mechanisms are close, but not identical in different joints under consideration. Studies have shown that multiple vortexes observed in the titanium-titanium aluminide joint are rare and occasional in the copper-titanium joint. One thing in common for the studied titanium-titanium aluminide joints is the disordering process observed as one approaches the contact surface. We are speaking about formation of disordered phases with BCC and HCP lattices. Disordered phases compared to other (О+a<sub>2</sub>) phases contained in the aluminide feature higher plasticity and toughness. The disordering process is one of the processes that ensure self-organization during explosive welding. The self-organization process during welding of aluminum and tantalum is an alternative for the above-mentioned disordering process. This refers to formation of the intermetallic phase of Al<sub>3</sub>Ta. Aluminum is one of the few metals that cannot be glued without preliminary chemical surface treatment. Nevertheless, a welded joint between aluminum and tantalum has been accomplished due to a remarkable feature of explosive welding: self-cleaning of welded surfaces due to cumulative effect.