Statistical mechanics of kinks on a gliding screw dislocation

Max Boleininger , Martin Gallauer , Sergei L Dudarev , T D Swinburne (1, 2) , Daniel R Mason , Danny Perez

1 CNRS - Centre National de la Recherche Scientifique
2 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille

The ability of a body-centered-cubic metal to deform plastically is limited by the thermally activated glide motion of screw dislocations, which are line defects with a mobility exhibiting complex dependence on temperature, stress, and dislocation segment length. We derive an analytical expression for the velocity of dislocation glide, based on a statistical mechanics argument, and identify an apparent phase transition marked by a crossover temperature above which the activation energy for glide effectively halves, changing from the formation energy of a double kink to that of a single kink. The analysis is in quantitative agreement with direct kinetic Monte Carlo simulations.

Domaines: Physique [physics]; Science des matériaux [cond-mat.mtrl-sci]

Max Boleininger, Martin Gallauer, Sergei L Dudarev, T D Swinburne, Daniel R Mason, et al.. Statistical mechanics of kinks on a gliding screw dislocation. Physical Review Research, 2020, 2, ⟨10.1103/physrevresearch.2.043254⟩. ⟨hal-03054069⟩