Effect of Low-Pressure Environments on the Joining Mechanism and process of electromagnetic pulse welding

Abstract The in-orbit assembly of space stations and the development of lightweight, multifunctional spacecraft have increased the demand for highly reliable joining technologies for dissimilar materials. Electromagnetic pulse welding (EMPW) is an advanced technology for joining dissimilar metals by high-velocity impact. The welding process and joining mechanism of EMPW plates under different vacuum environment pressures were investigated. The intrinsic correlation between environmental pressure and welding quality was revealed. The results showed that reducing environmental pressure increased the flyer plate velocity and the shear strength of the welded joint, and promoted the formation of complete welds. When the environmental pressure was reduced from 101 kPa to 0.1 kPa, the average peak load of the joint increased by 126%. The internal unwelded width of the weld decreased from 2.04 mm to 1.50 mm, and the weld area increased from 21.92 mm 2 to 35.80 mm 2 . Combined with S-ALE numerical simulation and microscopic analysis, it was found that the reduction in environment pressure increased the jet velocity, reduced the interfacial air gap and the interstitial void in the plate, and facilitated the generation of interfacial waveforms and the diffusion of elements. The results demonstrate that environmental pressure plays a critical role in EMPW. It governs interfacial jet formation, weld bead development, and joint performance. This study provides insights into reliable solid-state joining of dissimilar materials under low-pressure and vacuum environments.