Hardening due to copper precipitates in α-iron studied by atomic-scale modelling

We present results of a large-scale atomic-level study of dislocation–precipitate interaction. We have considered a 12 〈1 1 1〉 edge dislocation gliding in α-iron containing coherent copper precipitates of size from 0.7 to 6 nm over a temperature range from 0 to 450 K. The results demonstrate that some features are qualitatively consistent with earlier theoretical conclusions, e.g. the critical resolved shear stress (CRSS) is proportional to L−1 and ln(D), where L and D are precipitate spacing and diameter. Other features, which are intrinsic to the atomic-level nature of the dislocation–precipitate interaction, include strong dependence of the CRSS on temperature, dislocation climb and precipitate phase transformation.