| Abstract Scope |
It remains a challenge using single-scale approaches to fully address how the collective behavior of atomic-level kinks dictates the mesoscale dislocation dynamics and in turn, the macroscale performance of plastically deformed high-Peierls-barrier materials at finite temperature. Here we present a finite temperature coarse-grained atomistic approach to meet this challenge. Taking bcc iron and tungsten as model materials, we studied the dynamics of screw dislocation with its lengths ranging from 50nm to 5μm. One major finding is: the mobility of a screw dislocation is neither linearly dependent nor independent on its length when the kink nucleation rate is at the same level as the rate of kink annihilation on a very long dislocation line. This result can be used as a key supplement to a variety of higher scale approaches, such as kinetic Monte Carlo, dislocation dynamics, crystal plasticity, and phase field, and lay them on a firm atomistic foundation. |