Void and precipitate strengthening in alpha-iron: what can we learn from atomic-level modelling?

Defects created by radiation damage in materials can form obstacles to dislocation glide and thereby change the mechanical properties. Development of models of these effects requires understanding of the phenomena involved at both the atomic and continuum levels. This paper concentrates on the former level, and describes the application of a model developed recently to study the motion of an initially straight edge dislocation through a row of either voids or coherent copper precipitates in alpha-iron. The model can provide quantitative information on the stress-strain relationship, energy barrier profile and strength characteristics for dislocation-obstacle interaction, and the effects of stress, strain rate and temperature on the process can be investigated. New results on data and atomic-scale mechanisms associated with strengthening due to voids and precipitates over a range of size are presented and compared with earlier continuum treatments. It is shown that atomic-level simulation is essential for revealing information required for multiscale modelling of phenomena in radiation damage. (C) 2003 Elsevier B.V. All rights reserved.