Interface bonding and mechanical properties of large explosively welded titanium/aluminum composite pipes

The interfacial bonding and mechanical properties of a TC1/1060/6061/1060/TC1 explosively welded composite pipe were investigated in this work. The interface morphology, grain morphology, and element diffusion of the composite pipe were analyzed using electron microscopy, electron backscatter diffraction, energy dispersive spectroscopy, and X-ray diffraction. The results showed that the microstructure of the inner and outer TC1 welds transformed from coarse β grains to martensitic α′ phase, thus improving the hardness, wear resistance, and toughness of the base metal. The TC1/1060 interface weld exhibited an evident and appropriate width diffusion area, and direct bonding occurred at the TC1/1060 interface. and there was no intermetallic compound at the interface, indicating that the composite pipe had a good bonding quality. The micro- and macro-mechanical properties of the composite pipe were analyzed by performing a microhardness test, tensile test, and tensile shear test. The results showed that the welds of each layer had little effect on the macro-mechanical properties of the material but significantly influenced the overall ductility of the composite pipe material. The composite pipe material exhibited a layered failure form when subjected to tensile fracture, which imparted it with a better ductility. Because delamination damage starts from the welds of each layer, the overlap and closeness of the welds of each layer should be avoided when applying the proposed method in the preparation of composite pipes.