A phenomenological dislocation mobility law for bcc metals

Giacomo Po, Yinan Cui, David Rivera, David Cereceda, Tom D. Swinburne, Jaime Marian, Nasr Ghoniem

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

Dislocation motion in body centered cubic (bcc) metals displays a number of specific features that result in a strong temperature dependence of the flow stress, and in shear deformation asymmetries relative to the loading direction as well as crystal orientation. Here we develop a generalized dislocation mobility law in bcc metals, and demonstrate its use in discrete Dislocation Dynamics (DD) simulations of plastic flow in tungsten (W) micro pillars. We present the theoretical background for dislocation mobility as a motivating basis for the developed law. Analytical theory, molecular dynamics (MD) simulations, and experimental data are used to construct a general phenomenological description. The usefulness of the mobility law is demonstrated through its application to modeling the plastic deformation of W micro pillars. The model is consistent with experimental observations of temperature and orientation dependence of the flow stress and the corresponding dislocation microstructure.

Original languageEnglish (US)
Pages (from-to)123-135
Number of pages13
JournalActa Materialia
Volume119
DOIs
StatePublished - Oct 15 2016
Externally publishedYes

Keywords

  • bcc metals
  • Dislocation mobility
  • Non-Schmid effects
  • Tungsten

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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