Breakdown of Schmid's law in micropillars

The validity of Schmid's law in micropillar samples is assessed by a simulation scheme in which the critical stress to operate a slip system is determined by the free lengths of dislocations pinned by intersection points imposed by dislocations lying on other slip planes. At fixed dislocation density, yielding occurs predominantly on the slip system with the maximum Schmid factor when the sample size is large, but as the sample size reduces, other slip systems have an increasing probability of operating. (c) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.