Kinetics of dislocation cross-slip: A molecular dynamics study

E Oren and E Yahel and G Makov, COMPUTATIONAL MATERIALS SCIENCE, 138, 246-254 (2017).

DOI: 10.1016/j.commatsci.2017.06.039

The kinetics of cross-slip and annihilation of a screw dislocation dipole in face-centered cubic (FCC) copper crystals were studied by multiple molecular-dynamics simulations of long (200b) dislocations at selected stresses and temperatures with the aim to account for the thermally activated nature of the cross-slip process. A novel cross-slip mechanism was identified; this mechanism required the formation of a finite length constriction before cross-slip could be initiated. It was shown that point constrictions are not the transition state of cross- slip. A study of the kinetics confirmed that cross-slip is a first-order process. By fitting the rate constant to an Arrhenius form, the activation energy was found to be 1:05 eV +/- 15%. The activation volume for the Escaig stress in the glide plane was in the range of 5-40b(3), and the prefactor for the rate constant was evaluated to be 1 THz/b. (C) 2017 Elsevier B.V. All rights reserved.

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