Abstract:
Cold spray (CS) is a solid-state technique for producing metallic coatings through high-velocity powder particle deposition. In this work, large-scale molecular dynamics (MD) simulations were performed to model the sequential impact of gold particles to investigate the deformation behavior of the particles and the evolution of their microstructure during the earliest stage of coating formation. Gold was chosen as a prototypical metal with a face-centered cubic (FCC) structure without a significant native oxide layer. A quasi-2D model was used to achieve particle diameters of 100 nm while preserving essential deformation physics. Phenomena such as jetting, localized overheating, and interfacial amorphization were observed in the simulations. Subjected to extreme strain rates, the particles underwent severe plastic deformation and developed high dislocation densities (~1017 m 2), which reorganized into cellular substructures during recovery. Dynamic recrystallization promoted ultrafine grain formation near particle-particle and particle-substrate interfaces, while larger grains were found in the interior of the highly deformed particles. The heterogeneous simulated microstructure resembled the microstructure observed in microscopy of CS coatings. These results demonstrate that MD simulations can provide insights into the fundamental physical mechanisms that drive microstructural evolution during the initial formation of the coating, despite the simplified initial conditions and well-known limitations in length and time scales.
Referência:
PEREIRA, Luan de Moraes; RAHMATI, Saeed; DANNINGER, Leonardo Rodrigues; ZÚÑIGA, Alejandro; JODOIN, Bertrand; VEIGA, Roberto Gomes de Aguiar. Initial formation of a metallic coating inclod spray: a molecular dynamics study. Computational Materials Science, v.269, 114724, 13p., 2026.
Acesso ao artigo no site do Periódico:
https://www.sciencedirect.com/science/article/pii/S0927025626002430