Numerical simulation of cold spray coating

In cold spray coating, bonding happens when the velocity of the particles exceeds a certain so called ‘critical velocity’ (CV). The CV is affected by many process parameters. Therefore it serves as a representative parameter for verification of coating quality. Formerly, researchers have demonstrated that lower CV for a process leads to a better coating quality and demands less energy consumption. In this study, based on the well-recognized hypotheses that CV is related to adiabatic shear instability induced by high strain rate deformation during the impact, a numerical model of cold spray process is developed aimed to calculate the CV. The challenging problem of detecting the CV using the discrete output of numerical simulation has been solved applying Wavelet transformation and the second derivative of the physical parameters in Sobolev space. The results are compared with the other numerical models and the experimental results available in the literature.

Research highlights
► A model of the cold spray process is developed to estimate the critical velocity.
► An original method to investigate the shear instability of the particle is developed.
► The results show a good correspondence with published experimental data.