On Simulation of Multi-Particle Impact Interactions in the Cold Spray Process

The cold spray process consists of coating build-up by sequential impact, deformation and bonding of many particles. Therefore, formation and properties of a deposited layer are not only affected by the impact behavior of a single particle, but also by subsequent impact events. To investigate the material behavior under such conditions, impact of multiple particles in cold spray was studied here by the finite element method. Effects of high strain rates and temperature on material yield and failure criteria were considered. Particle conditions prior to impact were derived from fluid dynamics calculations. To predict sticking behavior of the particle, an interfacial cohesive strength parameter was defined between the particle and the substrate. The effects of temperature and particle positioning were examined for three particle impacts. In addition, simulations involving 100 consecutive particle impacts were carried out, and findings were compared with experimental observations. Results showed that subsequent impacts have a large effect on the previously impacted particles for cohesion, degree of deformation, and residual stresses.