Atomistic dislocation core energies and calibration of non-singular discrete dislocation dynamics

被引：12

作者：

Hu Y. ^{[1
]}

Szajewski B.A. ^{[2
]}

Rodney D. ^{[3
]}

Curtin W.A. ^{[1
]}

机构：

[1] Laboratory for Multiscale Mechanics Modeling (LAMMM), National Centre for Computational Design and Discovery of Novel Materials (NCCR MARVEL), École Polytechnique Fédérale de Lausanne, Lausanne

[2] Simulation Sciences Branch, U.S. Army Research Laboratory, Aberdeen Proving Ground, 21005-5066, MD

[3] Institut Lumière, Matière, UMR 5306, Universitè de Lyon, Villeurbanne

来源：

Modelling and Simulation in Materials Science and Engineering | 2020年 / 28卷 / 01期

关键词：

atomistic simulation; discrete dislocation dynamics; dislocation core energy; dislocation line tension;

D O I：

10.1088/1361-651X/ab5489

中图分类号：

O7 [晶体学];

学科分类号：

0702 ; 070205 ; 0703 ; 080501 ;

摘要：

The total energy of an atomistic dislocation includes contributions from the inelastic/large-distortion 'core' region. Capturing this inelastic 'core' energy is important, especially for dislocations with a curvature in the 10-100 nm scale. Current implementations of discrete dislocation dynamics (DDD) mesoscale simulations either approximate or neglect the core energy and so do not provide consistency with fully-atomistic studies. Using established interatomic potentials for FCC metals, the total dislocation energy is computed directly in atomistic simulations of straight dislocations and a core energy at any desired cut-off core radius is obtained as a function of dislocation character. A proper introduction of the atomistic core energy into the ParaDiS DDD code that uses a non-singular theory (Cai et al 2006 J. Mech. Phys. Solids 54 561-87) is then presented. The resulting atomistically-informed ParaDiS DDD is used to simulate the periodic bow-out of edge and screw dislocations in near-elastically-isotropic aluminum at various length and stress, with comparisons to fully-atomistic simulations. Generally good agreement is obtained between DDD and atomistics, with the best agreement achieved using a non-singular regularization parameter in the range of a = 5 - 10b. The analysis is then extended to compute the core energy of the Shockley partial dislocations that arise in the dissociation of perfect dislocations in fcc metals. © 2019 IOP Publishing Ltd.

引用

共 42 条

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