P. H. Liao, C. Coddet, University of Technology Belfort-Montbeliard, Belfort Cedex, France; W. Y. Li, Northwestern Polytechnical University,, Xi'an, China; C. J. Li, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, China
Cold spraying, as an emerging coating technique in recent years, has attracted worldwide interest for the fast deposition of high-quality metallic coatings. Many investigators have examined this process by both experiment and numerical simulation on the processing parameters, microstructure and corresponding properties of the deposits. However, there are still some underlying problems to be clarified. In this study, a comprehensive examination of deformation of Al particles upon impacting on Al substrate was conducted by using the Arbitrary Lagrangian Eulerian (ALE) methods to clarify the deposition characteristics of Al coatings and effect of surface oxide films in cold spraying. It was found that the deformation behaviour of Al particles is different from that of Cu particles under the same impact conditions owing to its lower density and thus less kinetic energy upon impact. The results indicate that the Al particles needs a higher velocity to reach the same flattening ratio and compression ratio with those of Cu particles, which is consistent with the experiment observation that Al particles had a high critical velocity than Cu. On the other hand, the numerical results also show that the oxide films at particle surfaces influences significantly the bonding process between the particles and substrate. The inclusions of the crushed oxide films at the interfaces between the depostied particles inhibit the bonding and lower the effective bonding areas.
Summary: In this study, a comprehensive examination of deformation of Al particles upon impacting on Al substrate was conducted by using the Arbitrary Lagrangian Eulerian (ALE) methods to clarify the deposition characteristics of Al coatings and effect of surface oxide films in cold spraying.
