Investigation on mechanical property of annealed copper particles and cold sprayed copper coating by a micro-indentation testing

In this study, the large annealed spherical copper powder (-120 + 150 mesh) was cold sprayed on a copper substrate. Microstructures of the annealed Cu particles and cold sprayed Cu coating were characterized by optical microscope and scanning electron microscope, and the mechanical property of the Cu particles and the Cu coating were examined by a micro-indentation testing. The hardness and Young's moduli of the Cu particles and Cu coating were determined by the method of Oliver and Pharr under the different test forces. Results show that the annealed Cu particles present more homogeneous and lower mechanical property than that of the deformed zones of the cold sprayed Cu coating, and the large deformed zone has the different mechanical property from that of the small deformed zone of the cold sprayed Cu coating because of the strong work-hardening effect on the coating. In addition, the regular variation tendency of hardness and the irregular variation tendency of Young's moduli could be explained by the effect of indentation size effect and different degrees of deformation damage, respectively. (C) 2012 Elsevier Ltd. All rights reserved.