Cold gas dynamic spraying (CGDS) is a solid-state metal deposition using a high-velocity particles impact. Here, an atomistic analysis of such an impact is investigated via a molecular dynamics (MD) simulation of an aluminium system. A three-dimensional MD model is used to capture the transient evolution of stress, shear strain, and temperature upon impact. The simulations reveal that strongly non-uniform shear localization at the interface triggers jetting and induces localized temperature rise, leading to thermal softening with an enhanced atomic mixing that facilitates the metallurgical bonding at the particle/substrate interface. The time dependant analysis of the structures produced by the collision indicates impact-induced disordering and local structure transformations that consist of FCC-to-HCP/BCC-like media and amorphous-like atoms within a highly deformed zone. A dense dislocation network is generated showing at a high spatial resolution the process of dislocation nucleation, motion, and interaction under the high strain-rate shearing. The radial distribution function (RDF) evolution from 0 ps to 16 ps further quantifies the lattice distortion along with the subsequent relaxation associated with the bonding development. These findings show that the interfacial bonding emerges from a tightly coupled sequence of interfacial shear localization and jetting, accompanied by a localized heating/softening and defect-assisted atomic rearrangement. The atomistic insights provide a physical understanding and characterization of the interfacial dynamic processes in cold spraying at the atomic scale. References 1. Rahmati S, Veiga R G A, Jodoin B, et al. Crystal orientation and grain boundary effects on plastic deformation of FCC particles under high velocity impacts. J. Materialia, 2021, 15: 101004. 2. Reddy C D, Zhang Z Q, Msolli S, et al. Impact velocity-dependent bonding mechanisms in metal cold spray. J. Surface and Coatings Technology, 2022, 433: 128085.