Effect of solutes on dislocation motion in dilute hcp and bcc alloys

Tsuru, Tomohito   ; Itakura, Mitsuhiro  ; Yamaguchi, Masatake   ; Suzudo, Tomoaki   ; Wakeda, Masato*; Ogata, Shigenobu*; Chrzan, D.*

Unlike fcc metals, where dislocation motion associated with solutes is reproduced by the effect of solute on the stacking fault energy and conventional hardening law, solutes in bcc and hcp metals induce more unique effects such as softening and dramatic change in plastic deformation. Recently, modeling of dislocations based on first-principles calculations was developed, and the modeling for various crystallographic structure were systemized. Especially for BCC metals, solid-solution model was established based on the thermally-activated process of double-kink nucleation and kink migration related to Orowan's relation. While the Burgers vector of the primary slip system in HCP metals is generally dislocation, the slip plane differs depending on the material, which mainly belongs to basal and prismatic plane according to the its stacking fault energy. Solute atoms have a large variety of the influence on dislocation motion resulting in dramatic change in plastic deformation.