High speed impact behaviors of Al alloy particle onto mild steel substrate during kinetic deposition

During kinetic spraying or cold spraying process, high speed impact occurs between feedstock and substrate. The deformation in this production causes high strain rates, which are higher than in the normal metal-working operation. In this study in order to investigate the deformation at kinetic spraying process individual Al–Si particle deposition onto mild steel substrate was obtained from a low feeding rate and high gun scanning speed spraying experiment. Flattening ratios and particle strains were measured and calculated from 3D analysis of the attached particles. The indentation theories were used for analyzing deformation and impact behavior. The contact pressure during the impact process was expatiated as increasing with the particle velocity, but it could not rise at a notable rate because of the effect of the particle velocity on the impact particle deformation. The calculations showed that the impinging process had a contact time less than 0.1 ms and a mean particle strain rate exceeding 10^7 s^-1.