Bimetallic junctions of orthorhombic titanium aluminide with a titanium alloy

Bimetallic composites are obtained: orthorhombic titanium aluminide - titanium alloy (diffusion welding, explosion welding). Their phase composition and microstructure are studied by methods of X-ray diffraction analysis, metallography, X-ray spectrum microanalysis, scanning and transmission electron microscopy. It is revealed that the titanium alloy after diffusion welding mainly is back to its initial state whereas the aluminide appears to be transformed to a disordered BCC-phase. A multilayer nature of a diffusion zone is detected, the phases in the layers are identified. When approaching the contact boundary on either side the appropriate BCC phases occur. Mutual adjustment of BCC lattices on diffusion welding is beneficial factor for a high quality of the bimetals. Another important factor is the absence of a solid intermetallic layer near a contact surface, otherwise the embrittlement may occur. It is shown that after explosion welding the phase composition of materials studied mainly remains constant. But their structure changes completely. On both sides of the contact surface the structural elements are observed which are typical for severely deformed materials. Simultaneous occurrence of cellular structure, laminated structure and fresh grains testifies to the fact that various fragmentation stages are conditioned by nonuniformity of plastic deformation over the bulk of plates