In-situ observation of crack evolution in Ti/Al laminated composite

Ti/Al laminated composite fabricated by explosive welding has received widespread attention due to their potential in achieving excellent performance. However, investigations on the crack evolution and fracture behavior were still limited. In this paper, the morphology and elemental distribution of the bonding interface were investigated. And the crack initiation and propagation of Ti/Al laminated composite was investigated by in-situ tensile test. It is shown that local melted zone (LMZ) was formed along the wavy interface, which was mainly consisted of TiAl2 + TiAl3 intermetallic compounds. The brittle intermetallic compounds on the LMZs are places where cracks initiate. As the internal stress accumulation, cracks generate at the tip of the wavy interface where the Ti layer is thinnest, and they locally form delamination along the interface. Subsequently, the crack tip is released from the Ti layer, leading to a catastrophic fracture to the whole Ti layer. Finally, the crack propagates to the Al layer until the material eventually fractured.