Effects of interlayer on the interfacial microstructures and thermomechanical kinetics of explosive welded 2A14 aluminum alloy-niobium composite

The explosive welding of 2A14 aluminum alloy and niobium with and without a 1060 Al interlayer is investigated by experiments and a two-step numerical simulation. Microstructure observations revealed a continuous molten layer with plenty of micro-defects at the joint interface by direct welding, and for the welding situation with an interlayer, straight and curled joints devoid of imperfections were obtained at the upper and lower interfaces, respectively. The tensile-shear strength for the direct welded samples was 84.4 MPa, while a rise of 38.2% was achieved for the composite with an interlayer. The coupled Lagrange-Eulerian simulation showed a dramatic decline in impact velocity and an obvious increase in collision area and duration due to the insertion of the interlayer, the resulting less kinetic energy loss at the joint interfaces eliminates the formation of the intermetallic compounds. In addition, the smoothed particles hydrodynamics simulation demonstrated that the distribution of strain, temperature, and pressure is more pronounced at the lower interface, and different bonding processes were elucidated for these two interfaces. The introduction of the interlayer strengthened the weldment by adjusting the way the interface accommodates the impact-induced strain.

Automated summary

This study investigates the explosive welding of 2A14 aluminum alloy and niobium with and without a 1060 Al interlayer through experiments and numerical simulation. The results show that direct welding results in a continuous molten layer with micro-defects at the joint interface, while the presence of an interlayer leads to straight and curled joints without imperfections. The tensile-shear strength of the composite with an interlayer is increased by 38.2% compared to direct welding. The numerical simulation reveals that the interlayer reduces the impact velocity, increases collision area and duration, and minimizes kinetic energy loss at the joint interfaces, preventing the formation of intermetallic compounds.