Numerical Analysis of Residual Stresses Evolution in Aluminum Cold Spray Process due to Interface Bonding

Abstract: In order to investigate the influences of bonding behaviors at particle/substrate and particle/particle interfaces on the final residual stresses built up in the cold spray process, we have developed an interface contact model that accounts for both the cohesive and the interfacial thermal conduction effects to model the particle bonding. Using this new computational capability, the residual stress evolutions of cold sprayed Al6061 coating on Al6061 substrate have been systematically studied via 3D single-particle and multi-particle impact simulations. The results showed that the residual stress states of the systems can vary significantly depending on the interface mechanical and thermal bonding behaviors. The resultant residual stresses are largely introduced by both the kinetic peening and bonding effects rather than the subsequent thermal relaxation effect. Due to the interface bonding, the compressive stresses distribute mainly near the interface region. Away from the interface, the stress states change from compressive to tensile in both particle and substrate. Our results suggest that the interface bonding should be considered as one of the essential factors in determining the final residual stresses in simulations.

Keywords: Cold spray, Residual stress, Aluminum coating, Numerical simulation