Interdiffusion cross-high-entropy alloys, nano-multilayer foils, and Al interface: An atomistic simulation

Molecular dynamics simulation is used to investigate the interdiffusion across the interfaces of high-entropy alloys (HEAs), reactive nano-multilayer foils (NMFs), NMFs, and crystalline Al. This study reveals highly asymmetric interdiffusivity within adjacent reactive NMFs and HEAs, exhibiting strong temperature dependency. Abnormal interdiffusion is observed in the diffusion region, which originates from the original solid/liquid interface. The mass transport phenomenon in this polyphase system involves an intricate interaction between coinstantaneous structure transformations: from the nano-multilayer structure to the solid-solution phase to a liquid–crystal Al phase. These transformations are driven by understated shifts in local bonding type with other atoms, wetting and spreading behaviors, and discrepancies in the inherent diffusivity of alloy components. The inherent complexity emerges as the heterostructure approaches equilibrium. This study discusses the important applications of interdiffusion in HEAs, NMFs, and crystalline Al fillers during the brazing process. This study sheds light on the interdiffusion in these systems and discusses its practical implications.