Analyzing the cross slip motion of screw dislocations at finite temperatures in body-centered-cubic metals: molecular statics and dynamics studies

T Suzudo and T Onitsuka and K Fukumoto, MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING, 27, 064001 (2019).

DOI: 10.1088/1361-651X/ab235e

The plasticity of body-centered-cubic metals at low temperatures is substantially determined by the screw-dislocation kinetics. Because the core of screw dislocations in these metals has a non-planar structure, its motion is complex. For example, although density functional theory predicts slip on a 110 plane, the actual slip plane at elevated temperatures differs from the prediction. In this work, we explored state-of-the-art atomistic modeling methods and successfully reproduced the transition of the slip plane through a temperature increase. We then devised an algorithm to analyze the activation of dislocation jump over the Peierls barrier and discovered a possible origin of this unexpected phenomenon: thermal fluctuation leads to the kink-pair nucleation for cross slip jumps with no transition of the dislocation core structure.

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