Dislocation segments with a Burgers vector of b = <100> were formed during deformation of body-centred-cubic metals by the interaction between dislocations with b = ½<111>. Such segments were also created by reactions between dislocations and dislocation loops in irradiated body-centered cubic metals. The obstacle resistance produced by these segments on gliding dislocations was controlled by their mobility, which was determined in turn by the atomic structure of their cores. The core structure of a straight <100> edge dislocation was investigated here by atomic-scale computer simulation for α-iron using three different interatomic potentials. At low temperature the dislocation has a non-planar core consisting of two ½<111> fractional dislocations with atomic disregistry spread on planes inclined to the main glide plane. Increasing temperature modifies this core structure and so reduces the critical applied shear stress for glide of the <100> dislocation. It was concluded that the response of the <100> edge dislocation to temperature or applied stress determines specific reaction pathways occurring between a moving dislocation and ½<111> dislocation loops. The implications of this for plastic flow in unirradiated and irradiated ferritic materials were discussed and demonstrated by examples.

Effects of Temperature on Structure and Mobility of the <100> Edge Dislocation in Body-Centred Cubic Iron. D.A.Terentyev, Y.N.Osetsky, D.J.Bacon: Acta Materialia, 2010, 58[7], 2477-82