Capturing cold-spray bonding features of pure Cu from in situ deformation behavior using a high-accuracy material model

Abstract

Cold spraying (CS) is a method that involves extreme deformation of materials on a very short temporal scale (approximately 10−8 s), and plays an important role in determining their bonding quality. A comprehensive and clear understanding of the CS deformation behavior is essential. In this study, a series of CS numerical simulations was performed using a self-developed material model, and a high simulation accuracy in determining the rebound velocities of microparticles was demonstrated through comparison with experimental results. The CS deformation behavior under different process conditions (i.e., different impact velocities and preheating temperatures) was discussed in detail to elucidate the particle deformation characteristics and reveal the underlying reason for its bonding with the substrate. The results show that during CS, the initial kinetic energy of the microparticles is primarily converted into the deformation energy of the microparticles and the substrate, 99% of which is dissipated via plastic deformation, while less than 1% is temporarily stored via elastic deformation, and can be eventually recovered to induce the rebound of the microparticles. In particular, the CS bonding exhibits distinct features due to jetting, the effective plastic strain, contact area, and energy, predicting the critical bonding conditions correctly.