Atomic-Level Investigation of Ni-W Film Growth on Al(001) Surface: Molecular Dynamics Simulation

Molecular dynamics (MD) simulations were performed to investigate the dynamic deposition behavior, growth mechanism, and mechanical properties of nickel–tungsten (Ni-W) alloy films on single-crystal Al(001) substrates. The results demonstrate that the incorporation of W atoms lowers the Ehrlich–Schwoebel (ES) barrier for Ni adatoms, facilitating downhill diffusion and effectively suppressing Volmer–Weber (VW) mode, thereby improving surface morphology and reducing film roughness. Additionally, W atoms exhibit a tendency to segregate at grain boundaries, inducing lattice distortion and structural disorder. With increasing W content (≥15 at%), the films undergo a transition from a nanocrystalline to an amorphous structure. Nanoindentation simulations reveal that film hardness increases with W content, with the strengthening mechanism being composition-dependent: dislocation pinning dominates at low W concentrations (≤5 at%), while the formation of an amorphous structure emerges as the primary strengthening mechanism at higher W contents (≥15 at%). This work elucidates the growth regulation and strengthening mechanisms of Ni-W films from an atomic-scale perspective, providing a theoretical foundation and simulation-driven guidance for the design and optimization of high-performance, environmentally benign Ni-W coatings.