Atomic modelling of strengthening mechanisms due to voids and copper precipitates in a-iron

Recently a model has been developed by Osetsky and Bacon to study edge dislocations moving over large distances on the atomic scale. It permits investigation of motion of a dislocation under different conditions of applied shear stress with constant or variable strain rate and temperature, and in the presence of obstacles. In this paper we apply the model to study the motion of an infinite straight but flexible edge dislocation through a row of either voids or coherent copper precipitates in bcc iron. Stress-strain curves, energy barrier profile and strength characteristics of obstacles and other dislocation configuration information have been obtained from the modelling and compared with continuum treatments. Some specific atomic-scale mechanisms associated with strengthening due to voids and precipitates over a range of size have been observed and discussed.