Determination of plastic constitutive properties of microparticles through single particle compression

There is a need for information on plastic properties of microparticles for application in powder technology. This includes powder compaction processes, in which densification involves particle deformation. The present paper reports on the evaluation of yield strength, ultimate tensile strength and the entire stress-strain relationship of single metallic particles, by combining mathematical modelling and compression tests using a modified nanoindenter. Development and application of the method is initially demonstrated for the case of copper particles of 13-87 mu m in diameter. The examined copper particles exhibited similar plastic properties to one another, but different to bulk copper. The method is further employed to work out plastic properties of a CoNiCrAlY powder, for which no bulk data exists. The findings are discussed in view of implications for cold spraying, where the deposition and coating characteristics are strongly influenced by plastic constitutive properties of particles. (C) 2015 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.