Microstructures and mechanical properties of the welded AA5182/HC340LA joint by magnetic pulse welding

Highlights: • The magnetic pulse welding of 5× aluminum alloy with high strength steel is performed. • The microstructure evolution of welding interface under different parameters is investigated. • The intermediate layer is characterized by high-resolution transmission electron microscope and electron diffraction pattern. - Abstract: Magnetic pulse welding (MPW) is an innovative joining technology for dissimilar materials. The MPW with high joining qualities could be realized between high strength steel and 5× aluminum alloys. In this work, the MPW joints between aluminum alloy (AA 5182) sheet and high-strength low alloy steel (HC340LA) sheet were prepared under various discharge energies. The mechanical properties and microstructure observations were employed to evaluate the joint performance. Results showed that a lower discharge voltage tended to cause joints with poor quality. When the discharge energy increased, the failure position gradually changed from the weld zone to the weaker base metal (Al) during quasi-static tensile tests. In addition, the effect of discharge energies on microstructure evolution in the intermediate layer was revealed by high-resolution transmission electron microscopy (HRTEM) and scanning electron microscope (SEM). Atomic-scale diffusion was found to be the mainly welding mechanism of the Al/Fe joint. The intermetallic compound (IMC) FeAl₂ and ultra-fine grains (UFG) were found in the intermediate layer under high discharge energy.