An Improved Model for Prediction of Critical Velocity of Cold-Spray by First-Principles Calculations

The first-principles calculation was applied to predict the critical velocity of Cu/Al cold-spray bonding for the first time. The bonding mechanism of cold-spray was clarified by analyzing the energy variation and atomic interaction during the cold-spray impact process. Our results showed that the shear deformation played a key role in the cold-spray bonding. The atomic interaction determined the effective absorption of impact kinetic energy and finally determined the successful bonding of the cold-spray. The heterogeneous atoms absorbed the impact kinetic energy by interatomic attraction to achieve cold-spray bonding, while the homogeneous atoms absorbed the impact kinetic energy by the deformation of interface layers. An excellent agreement between the predicted critical velocity and the experimental one could be obtained, especially for the heterogeneous material cold-spray. Our present method proved to be a simple and highly efficient computing method in critical velocity prediction. Most importantly, the critical velocity for cold-spray could be predicted without using any empirical or experimental parameters.