Structural analysis of aluminium-titanium-stainless steel three-layer composites produced by explosive welding

The present work aimed to study the morphological, microstructural, and mechanical properties of Al sheet-Ti sheet-SS sheet composites produced by explosion welding. Trimetallic composites with sound structure and very good mechanical behaviour were obtained. The mechanical performance of the produced composites makes them very appropriate for applications requiring increased lightness, corrosion resistance, and mechanical properties at high and low temperature. Regarding the weldability of the material trio, the type of the explosive mixture was found to have a strong influence on the results. Better conditions were achieved by using a mixture with a lower detonation velocity, as high detonation velocities are not appropriate for welding low melting temperature flyers, like aluminium alloys. Although IMC-rich zones were formed at the Al-Ti and Ti-SS interfaces of the composites, these regions were encompassed/accommodated by ductile interfacial waves, which allowed to overcome the brittleness of the IMC regions and to achieve composites with an improved performance. An encompassing literature-based study also allowed to infer that, regardless of the material couples being joined by EXW, the matrix of the intermediate regions formed at the weld interface is always richer in the main element of the welded couple with lower melting temperature.