Irreversibility of dislocation motion under cyclic loading due to strain gradients

SCRIPTA MATERIALIA

卷:129

Article

Stricker, Markus¹  Weygand, Daniel¹  Gumbsch, Peter^1,2 

[1] Karlsruhe Inst Technol, IAM, Kaiserstr 12, D-76131 Karlsruhe, Germany

[2] Fraunhofer IWM, Woehlerstr 11, D-79108 Freiburg, Germany

关键词: Irreversibility;    Plasticity;    Dislocation structure;    Bending;    Torsion;   

DOI  :  10.1016/j.scriptamat.2016.10.029

来源: Elsevier

【 摘 要 】

Mechanisms that make dislocation motion irreversible are associated with the formation of dislocation junctions and cross-slip, leaving dislocations trapped inside the specimen. Using Discrete Dislocation Dynamics simulations, we identify another mechanism that produces irreversible plastic deformation and leaves no or only very few dislocations inside the sample: Under cyclic loading, dislocations which pass the neutral plane during loading (pile-up formation), generate a slip step upon unloading. The explanation is an intrinsic asymmetry between the backward and forward motion. An additional bias may be introduced by the geometry of the specimen due to the shortening of the line length of dislocations. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

【 授权许可】

Free