A Numerical description of the motion of screw dislocation around solutes in tungsten alloys

Tsuru, Tomohito   ; Suzudo, Tomoaki   ; Itakura, Mitsuhiro  ; Wakeda, Masato*; Ogata, Shigenobu*

Effect of transmutation products such as Re and Os is one of the central issues on change in mechanical properties under neutron irradiation in fusion reactors. Especially, Re solutes in W affect not only hardening via radiation-induced precipitation but also significant softening effect. We explored softening/strengthening behavior in various solutes in W matrix by density functional theory (DFT) calculations combined with a solid solution model. In addition, we proposed a method for the dynamics motion of a screw dislocation based on kink nucleation and kink migration, in which Hamiltonian of a dislocation is described by line tension model. As a result of DFT calculations for various solutes, a clear trend was observed in the interaction energy between a solute and a screw dislocation, which has predominant influence on solid solution behavior.