Magnetic pulse welding of nickel and aluminum plates: structure and numerical simulations

This paper investigates the magnetic pulse welding (MPW) of commercially pure nickel and aluminum plates using a flat copper inductor scheme. The effect of impact angle (10° and 13°) and impact velocity on the interfacial microstructure, phase formation, and nanohardness was studied using optical microscopy, SEM, and TEM. The experimental results were correlated with smoothed particle hydrodynamics (SPH) simulations of the collision process and molecular dynamics (MD) simulations of atomic interdiffusion. The weld interface exhibited a transition from flat to wavy morphology with increasing impact velocity. The mixing zone had a nanograined structure with grain size mostly less than 100 nm, consisting of a nickel-in-aluminum solid solution with NiAl₃ and NiAl intermetallic particles. SPH simulations revealed that the sample welded at 10° exhibited higher interfacial temperatures (1370–1910 K) compared to the 13° sample (1320–1580 K). This promoted the formation of intermetallics and increased nanohardness values to 2.6–3.2 GPa, compared to 1.7–2.7 GPa for the 13° sample. At the end of the weld in the 10° sample, the temperature of 1910 K exceeded the local melting point of nickel, forming a continuous interlayer with a nanohardness of 9.2 GPa. MD simulations, using SPH-derived temperatures as input, showed that interdiffusion coefficients range from 0.5 to 7 × 10⁻⁸ m²/s. The growth of the mixing layers is governed by atomic diffusion at the beginning of the welds, while mechanical mixing dominates at the end.