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Grain boundary orientation effects on deformation of Ta bicrystal nanopillars under high strain-rate compression

Wang, L. and Zhao, F. and Zhao, F. P. and Cai, Y. and An, Q. and Luo, S. N. (2014) Grain boundary orientation effects on deformation of Ta bicrystal nanopillars under high strain-rate compression. Journal of Applied Physics, 115 (5). Art. No. 053528. ISSN 0021-8979. https://resolver.caltech.edu/CaltechAUTHORS:20140401-104129415

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Abstract

We investigate grain boundary (GB) orientation effects on deformation of Ta bicrystal nanopillars under high strain-rate, uniaxial compression with molecular dynamics simulations. The GB is of the ⟨110⟩90° twist grain boundary type. We vary the angle between the GB normal and the loading direction (θ) in the range of 0°–90° while keeping the GB type unchanged. The GB orientation has strong effects on deformation mechanism, yield stress, failure strain, and dynamics, due to the combined effects of Schmid factors in constituent crystals and resolved shear stress on the GB plane. Single crystal plasticity and GB deformation are competing factors, and the GB-initiated deformation mechanisms (stacking faults vs. twinning, and GB sliding) depend on the local stress level around the GB. The large Schmid factors in constituent single crystals for θ=0° lead to twinning in the single crystals and the lowest yield stress; the ensuing GB deformation is achieved via stacking fault formation due to premature stress relaxation. However, nanopillar deformation in the cases of higher angles is dominated by GB deformation largely in the form of twinning, driven by enhanced stress buildup. GB-initiated deformation in the high Schmid factor nanocrystal precedes and may drive that in the low Schmid factor nanocrystal. The details of twin/stacking fault nucleation and growth/shrinking, twin-twin interaction, and twin-GB interaction are also discussed.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1063/1.4864427DOIArticle
http://scitation.aip.org/content/aip/journal/jap/115/5/10.1063/1.4864427PublisherArticle
ORCID:
AuthorORCID
An, Q.0000-0003-4838-6232
Additional Information:© 2014 American Institute of Physics Publishing LLC. Received 23 December 2013; accepted 26 January 2014; published online 7 February 2014.
Issue or Number:5
Record Number:CaltechAUTHORS:20140401-104129415
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20140401-104129415
Official Citation:Grain boundary orientation effects on deformation of Ta bicrystal nanopillars under high strain-rate compression L. Wang, F. Zhao, F. P. Zhao, Y. Cai, Q. An and S. N. Luo J. Appl. Phys. 115, 053528 (2014); http://dx.doi.org/10.1063/1.4864427
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:44574
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:01 Apr 2014 18:22
Last Modified:03 Oct 2019 06:19

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