Bonding mechanism in Cu coating deposited on Al alloy substrate: Combining molecular dynamics simulation and experiment

L Shao and WW Li and QS Lu and N Xue and YW Chen and YC Wu and CQ Liu and YZ Liu and K Sajjad and Q Shi and CX Wang and JH Lv and MH Ye and T Zhou and JK Huang and L Zhu, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 942, 148703 (2025).

DOI: 10.1016/j.msea.2025.148703

Cold spray technology has emerged as a notable low-temperature method for depositing Cu and other ductile metals, offering significant advantages over traditional coating processes. However, the effective application of this technique requires optimizing key parameters, such as particle velocity, through a comprehension understanding of the physical mechanisms governing coating formation and bonding. To address this, molecular dynamics simulations using an advanced potential were employed to examine the influence of Cu particle on an Al alloy substrate at atomic resolution and picosecond timescales. The simulations explored temperature, von Mises stress and shear strain, dislocation line distribution, dislocation density and atomic diffusion at different particle velocities. Analysis of the Cu particle deformation reveals significant plastic deformation, while the particle flattening ratio shows little variation across velocities. Microstructural analysis reveals that the Cu particle undergoes severe plastic deformation upon impact, with dislocation density increasing with higher particle velocities, leading to grain refinement. The formation of Cu9Al4 and CuAl intermetallic phases at the interface indicates that atomic diffusion and recrystallization play critical roles in the bonding mechanism. Furthermore, localized temperature rise due to adiabatic shear-induced deformation facilitates the interfacial bonding. This research offers valuable insights into the adhesion mechanisms of cold spraying and the impact of particle velocity on the microstructure of Cu coating on Al alloy substrate.

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