The effect of size upon the mechanical behaviour and the void growth rate in a voided single crystal was studied using two-dimensional discrete dislocation dynamics. The simulations were based upon the methodology developed by Van der Giessen & Needleman (1995), which was extended to non-convex domains by the use of finite elements with embedded discontinuities by Romero et al. (2008). Square crystals (0.5 to 2.5μm) with an initial void volume fraction of 10% were deformed under plane strain conditions in uniaxial tension, uniaxial deformation and biaxial deformation. The results of the simulations revealed two size effects: one in the initial flow stress and strain-hardening rate of the voided crystal (smaller = stronger) and one in the void growth rate (smaller = slower). The magnitudes of both size-effects increased with triaxiality. The physical micromechanisms responsible for these size-effects were deduced from the simulation results.

An Analysis of the Size Effect on Void Growth in Single Crystals using Discrete Dislocation Dynamics. J.Segurado, J.Llorca: Acta Materialia, 2009, 57[5], 1427-36