Second-order junctions and strain hardening in bcc and fcc crystals

Axial ternary junctions, which were recently discovered by Bulatov et al.* [V.V. Bulatov et al., Nature 440 (2006) 1174], as well as zigzag ternary configurations, were classified according to crystallographic criteria in face-centered cubic (fcc) and body-centered cubic (bcc) metals. The determination of their average strength by dislocation dynamics simulations shows that ternary configurations induce a significant Taylor hardening in bcc crystals, but not in fcc crystals. In both cases, these configurations should enhance strain hardening through their contribution to the storage rate of dislocations. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.