Atomic scale simulation ofcross slip and s crew dislocation dipole annihilation

摘要

Atomistic simulations are used to study cross slip of a single screw dislocation as well as screw dislocation dipole a nnihilation in Cu. A configuration space path techniques is applied to determine, without presumptions about the saddle point, the minimum energy path of transition for cross slip. The cross slip process is that proposed by Friedel and Escaig, and the energy of the in-plane constriction initiating cross slip is determined. A minimum stable doploe hieht much smaller than previously inferred form experimental studies is found Relaxied screw dislocation doplores adopt a skew configuration due to the anisotropy of Cu. The path technique is applied to investigate annihilation o f stable screw dislocation doploes, and the energy barrier for annihilation as a function of doploe hiehht is determined for both homogeneous and heterogeneous cross slop leading to the annihilation. The results might be used as quantitative input into meso-/macor-scopical modelling approaches which rely on parameters deduced from either simulation or experiment,