Consolidation of nanoparticles - Development of a micromechanistic model

A micromechanism-based model is developed for nanoparticle densification du ring uniaxial and hydrostatic pressing. The model takes into account the ef fects on densification of agglomeration, bulk and surface impurities, fewer dislocations per particle and low stability of dislocations due to fine si ze, and other factors unique to nanoparticle systems. The model is applicab le to a general nanoparticle system, and is capable of predicting density, densification rate(s), dominant densification mechanisms, and microstructur al features, as a function of consolidation parameters. The present model i s the first rigorous and comprehensive attempt to extend the Helle-Easterli ng-Ashby model to the nanocrystalline grain-size regime. Predictions of the model were compared with experimental data on nanocrystalline copper and n anocrystalline molybdenum disilicide and observations reported in literatur e. A good agreement of model predictions with experimental data for a wide range of material and processing variables was observed. (C) 1999 Acta Meta llurgica Inc. Published by Elsevier Science Ltd. All rights reserved.