希薄Mg-Y合金における底面転位の運動過程に関する原子論的解析

抄録

We investigated the effects of the Y atom on the dislocation motion in Mg based on the atomistic approach. An interatomic potential for Mg-Y systems under the dilute conditions was developed and applied to evaluate interaction energies between the Y atom and <a> screw dislocation. From the obtained interaction energy landscape, we found that the Y atom acts as resistance for the dislocation motion on the basal plane; although the Y atom promotes the kink-pair nucleation on the Shockley partial dislocations, it significantly impedes the kink-pair migration. We estimated the critical resolved shear stresses for the basal plane at a concentration of 1 at.% Y in Mg-Y alloy based on the Orowan model. The obtained result suggested that the hardening of the basal slip was achieved by the trapping effect of local obstacles of solute Y, which significantly disturbs kink-migration process and slows down the dislocation motion.