A modified plastic yield function is proposed to predict the consolidation behavior of nanostructured metal powders and metal-matrix nanocomposite powders under uniaxial compaction. The validity of the model is verified for nanocrystalline Al6063 (similar to 100 nm) alloy reinforced without and with 0.8 vol.% Al2O3 nanoparticles (similar to 25 nm). The plastic deformation propensity of these powders is analyzed by linear compaction equations. The yield stress of the powder compacts is shown to be influenced by the nano-scale grains and the reinforcement nanoparticles. (C) 2011 Elsevier B.V. All rights reserved.