Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5016720 | International Journal of Plasticity | 2017 | 32 Pages |
Abstract
The Escaig stress, i.e. the shear stress perpendicular to the Burgers vector, modulates the stacking fault area between two partials of a full dislocation, in turn, affects the mobility of the dislocation. In this paper, using the newly improved semi-discrete variational Peierls-Nabarro (SVPN) model we studied the variation of Peierls stress (Ïp) of dislocations in face-centered-cubic crystals with respect to the Escaig stress. We found that Ïp quasi-periodically oscillates and the oscillation gradually decreases with the increase of Escaig stress. This quasi-periodic variation of Ïp can be mathematically described by the combination of a sinusoidal and an exponential function, and further accounted for by the variation of the stacking fault width (SFW) between two partials during their movement under applied stress. For the maximum Ïp, SFW is about integral multiples of the Peierls period. For the minimum Ïp, SFW is around half-integral multiples of Peierls period. The variation of Ïp is associated with the oscillation magnitude of SFW from half-integral multiples to integral multiples of the Peierls period and then back to integral multiples of Peierls period caused by the Escaig stress. Molecular dynamics (MD) simulations further examined quasi-periodic variation of Ïp, validating the SVPN model's capability of predicting sophisticated behavior of dislocation under applied stress.
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Authors
Guisen Liu, Xi Cheng, Jian Wang, Kaiguo Chen, Yao Shen,