Interfacial characteristics of FeNiCrCoMn/FeNiCr bimetallic explosive welding using molecular dynamics simulation

TTB Ngo and VT Nguyen and TH Fang, MATERIALS TODAY COMMUNICATIONS, 49, 114203 (2025).

DOI: 10.1016/j.mtcomm.2025.114203

Explosive welding (EW) enables solid-state bonding between dissimilar metals through high-velocity impact, yet the ultrafast atomic-scale processes governing bond formation remain poorly understood. In this work, molecular dynamics (MD) simulations were employed to investigate the interfacial behavior of EW between FeNiCrCoMn high-entropy alloy (HEA) and FeNiCr medium-entropy alloy (MEA), representing the first atomistic exploration of EW in multi-principal-element systems. The effects of collision angle (5 degrees-20 degrees) and impact velocity (750-3750 m/s) were systematically analyzed to reveal their influence on interfacial temperature, stress, diffusion, and structural evolution. The results show that moderate collision angles (10 degrees-15 degrees) and velocities (1250-2250 m/s) promote optimal bonding characterized by concentrated shear stress, localized amorphization, and stacking-fault (SF) formation, leading to a maximum ultimate tensile strength (UTS) of 6.17 GPa. Excessive energy input (>= 3750 m/s) disperses stress and induces interfacial damage, reducing joint integrity. Bonding in HEA/MEA joints arises from shear-induced amorphization and sluggish diffusion, driven by lattice distortion and configurational entropy. These findings bridge the gap between experiments and atomic mechanisms, explaining how compositional complexity alters the bonding pathway in explosive welding. The established framework provides a predictive basis for optimizing EW parameters in HEA and MEA systems.

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