PNADIS: An automated Peierls-Nabarro analyzer for dislocation core structure and slip resistance

Abstract

Dislocation is one of the most critical and fundamental crystal defects that dominate the mechanical behavior of crystalline solids, however, a quantitative determination of its character and property in experiments is quite challenging and limited so far. In this paper, a fully automated Peierls-Nabarro (P-N) analyzer named PNADIS is presented; a complete set of the character and property of dislocation can be automatically derived, including the dislocation core structure. Peierls energy and stress, pressure field around dislocation core, solute/dislocation interaction energy, as well as the energy barrier and increase in critical-resolved shear stress at 0 K for solid solution strengthening. Furthermore, both one-dimensional (1D) and two-dimensional (2D) P-N models are implemented to meet the demand to analyze the character and property of dislocation for not only simple FCC and HCP structures but also complex crystals. The implementation of this code has been critically validated by a lot of evaluations and tests including 1D P-N model for complex crystals, 2D P-N model for FCC and HCP metals, pressure field around dislocation core, and solid solution strengthening for alloys. We expect that the automated feature of this code would provide a high-efficiency solution for determining the character and property of dislocation.

Program summary

Program title: PNADIS

Program Files doi: http://dx.doi.org/10.17632/whk6wdy3nn.1

Licensing provisions: GNU General Public License 3

Programming language: MATLAB

Nature of problem: To determine automatically the character and property of dislocation, including dislocation core structure, Peierls stress, pressure field around dislocation core and solid solution strengthening, for not only FCC and HCP structures but also complex crystals.

Solution method: The generalized stacking fault energy is firstly fitted by Fourier expansion, and meanwhile an appropriate trial function of disregistry vector is chosen. Afterwards, a least square minimization of the difference between elastic resistance and restoring force for one-dimensional Peierls-Nabarro model, or a global minimization of the total dislocation energy via particle swarm optimization or genetic algorithm for two-dimensional Peierls-Nabarro model, will be performed to determine the dislocation core structure of complex crystals, or FCC and HCP structures. Finally, the Peierls stress, pressure field around dislocation core and solid solute strengthening are derived from the calculated dislocation core structure. (C) 2019 Elsevier B.V. All rights reserved.