Dislocation stability and deformation mechanisms of iron aluminides and silicide

Elastic stability of dislocations in FeAl alloys and Fe3Si was examined wit h respect to the formation of jog pair(s) on a straight dislocation as well as the kink-pair formation. Dislocation configurations from annealed and d eformed microstructures available in the literature are consistent with the predictions based on elastic instability. The difference in the formation enthalpy between a jog pair and a kink pair was obtained, and the activatio n enthalpy of a jog-pair pinning mechanism for edge dislocations was prescr ibed. Discussion is given on the driving forces for the pinning mechanisms, including the role of inhomogeneous internal stress in FeAl single crystal s. (C) 1999 Acta Metallurgica Inc. Published by Elsevier Science Ltd. All r ights reserved.