Campus Units

Materials Science and Engineering, Ames Laboratory

Document Type

Article

Publication Version

Accepted Manuscript

Publication Date

3-2017

Journal or Book Title

International Journal of Plasticity

Volume

90

First Page

146

Last Page

155

DOI

10.1016/j.ijplas.2016.12.009

Abstract

When grain sizes are reduced to the nanoscale, grain boundaries (GB) become the dominant sources of the dislocations that enable plastic deformation. We present the first molecular dynamics (MD) study of the effect of substitutional solutes on the dislocation nucleation process from GBs during uniaxial tensile deformation. A simple bi-crystal geometry is utilized in which the nucleation and propagation of dislocations away from a GB is the only active mechanism of plastic deformation. Solutes with atomic radii both larger and smaller than the solvent atomic radius were considered. Although the segregation sites are different for the two cases, both produce increases in the stress required to nucleate a dislocation. MD simulations at room temperature revealed that this increase in the nucleation stress is associated with changes of the GB structure at the emission site caused by dislocation emission, leading to increases in the heats of segregation of the solute atoms, which cannot diffuse to lower-energy sites on the timescale of the nucleation event. These results contribute directly to understanding the strength of nanocrystalline materials, and suggest suitable directions for nanocrystalline alloy design leading toward structural applications.

Comments

This is a manuscript of an article published as Borovikov, Valery, Mikhail I. Mendelev, and Alexander H. King. "Effects of solutes on dislocation nucleation from grain boundaries." International Journal of Plasticity 90 (2017): 146-155. DOI: 10.1016/j.ijplas.2016.12.009. Posted with permission.

Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.

Copyright Owner

Elsevier Ltd.

Language

en

File Format

application/pdf

Published Version

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