Microstructure and fracture mechanism of Ti/Al layered composite fabricated by explosive welding

Ti/Al layered composite was fabricated by explosive welding (EXW). The aim of this work is to study the microstructure and phase composition of the Ti/Al interface region and its effect on the fracture behavior. The interface region is composed of a wavy bonding zone and some local melted zones (LMZs). Ti3Al intermetallic compound is formed in the LMZ, and highly refined Ti grains and Al grains are formed around the Ti3Al compound. The bonding zone is composed of a mixture of Al3Ti intermetallic compound and recrystallized Al grains. Furthermore, the Al3Ti compound forms a good semi-coherent interface with the Ti matrix. In-situ tensile test shows that under tensile force, microcracks could be easily induced by the hard Ti3Al compound in the LMZ. Nevertheless, the initial defects did not demonstrate a tendency for further propagation. As the deformation increases, cracks nucleated at the Al3Ti compound of the bonding zone, forming locally delamination. Finally, the fracture occurred at the place where the delamination first formed.