Interfacial microstructure and dynamic compressive behavior of explosively welded TA2/AZ31B/7075Al multilayer composites

Lightweight Ti/Mg/Al multilayer composites have considerable application potential in aerospace and protective structures. However, their overall performance strongly depends on the bonding quality and microstructural evolution of heterogeneous interfaces. In this study, TA2/AZ31B/7075Al composite plates containing with 1060Al interlayers were fabricated by explosive welding, and their interfacial morphology, elemental distribution, crystallographic characteristics, and static and dynamic compression behaviors were systematically investigated. The TA2/1060Al and 1060Al/7075Al interfaces exhibited nearly flat bonding morphologies without obvious defects, whereas the two Al/Mg interfaces showed typical wavy structures. The wavelength and amplitude of the upper 1060Al/AZ31B interface were approximately 300 μm and 67 μm, respectively, which were significantly larger than those of the lower AZ31B/1060Al interface. Distinct microstructural evolution characteristics were observed near different interfaces, including {10-12} twinning on the TA2 side, grain refinement and recrystallization on the 1060Al side, and the formation of continuous Mg 17 Al 12 intermetallic compound layers at the two Al/Mg interfaces. The 7075Al side near 1060Al/7075Al showed more pronounced deformation substructures and higher local misorientation. Under static compression, the maximum compressive strengths of the parallel and series configuration specimens were 514 MPa and 346 MPa, respectively. Under dynamic compression, these values increased to 585 MPa and 382 MPa, respectively. The failure behavior of the composite plates was mainly controlled by shear fracture of the AZ31B layer and delamination at the Al/Mg interfaces, which became more pronounced under high-strain-rate loading. These findings provide guidance for the interfacial design of lightweight Ti/Mg/Al laminated functionally graded composites to a certain extent.