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Title: Orientation dependent spall strength of tantalum single crystals

Abstract

We report that it is generally recognized that single crystals exhibit orientation-dependent elastic and plastic responses. However, it is less known how the dynamic tensile, or spall, strength depends on crystalline orientation, especially for BCC materials. It has been previously shown that the dynamic tensile strength of FCC materials is highly dependent on their plastic response under compression, with a direct correlation between plastic deformation and spall strength. In BCC materials like Ta, where the primary deformation mechanism at high strain rates is a combination of slip and twinning, the quantitative dependence of spall strength on these deformation mechanisms is less understood. To fill this gap in our knowledge, a series of non-equilibrium molecular dynamics simulations are completed for six tantalum single crystal orientations: <001>, <011>, <111>, <013>, <112>, <149>, to explore the role of directional anisotropy on ductile spallation. Our results show that due to the role of non-Schmid and release effects in BCC Ta, the evolution of plasticity follows a complex trajectory through shock compression, release, and tension. Orientations that contain residual twinning deformation have a reduced spall strength proportional to the amount of twinning present. Lastly, twins and their intersections function as regions of increased stress localizationmore » within the system due to compatibility requirements and their interactions with dislocations.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA); USDOE Laboratory Directed Research and Development (LDRD) Program
OSTI Identifier:
1467282
Alternate Identifier(s):
OSTI ID: 1703855
Report Number(s):
LA-UR-18-22656
Journal ID: ISSN 1359-6454
Grant/Contract Number:  
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 159; Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; tantalum, shock

Citation Formats

Hahn, Eric Nicholas, Gray, George Thompson III, Germann, Timothy Clark, and Fensin, Saryu Jindal. Orientation dependent spall strength of tantalum single crystals. United States: N. p., 2018. Web. doi:10.1016/j.actamat.2018.07.073.
Hahn, Eric Nicholas, Gray, George Thompson III, Germann, Timothy Clark, & Fensin, Saryu Jindal. Orientation dependent spall strength of tantalum single crystals. United States. doi:10.1016/j.actamat.2018.07.073.
Hahn, Eric Nicholas, Gray, George Thompson III, Germann, Timothy Clark, and Fensin, Saryu Jindal. Fri . "Orientation dependent spall strength of tantalum single crystals". United States. doi:10.1016/j.actamat.2018.07.073. https://www.osti.gov/servlets/purl/1467282.
@article{osti_1467282,
title = {Orientation dependent spall strength of tantalum single crystals},
author = {Hahn, Eric Nicholas and Gray, George Thompson III and Germann, Timothy Clark and Fensin, Saryu Jindal},
abstractNote = {We report that it is generally recognized that single crystals exhibit orientation-dependent elastic and plastic responses. However, it is less known how the dynamic tensile, or spall, strength depends on crystalline orientation, especially for BCC materials. It has been previously shown that the dynamic tensile strength of FCC materials is highly dependent on their plastic response under compression, with a direct correlation between plastic deformation and spall strength. In BCC materials like Ta, where the primary deformation mechanism at high strain rates is a combination of slip and twinning, the quantitative dependence of spall strength on these deformation mechanisms is less understood. To fill this gap in our knowledge, a series of non-equilibrium molecular dynamics simulations are completed for six tantalum single crystal orientations: <001>, <011>, <111>, <013>, <112>, <149>, to explore the role of directional anisotropy on ductile spallation. Our results show that due to the role of non-Schmid and release effects in BCC Ta, the evolution of plasticity follows a complex trajectory through shock compression, release, and tension. Orientations that contain residual twinning deformation have a reduced spall strength proportional to the amount of twinning present. Lastly, twins and their intersections function as regions of increased stress localization within the system due to compatibility requirements and their interactions with dislocations.},
doi = {10.1016/j.actamat.2018.07.073},
journal = {Acta Materialia},
issn = {1359-6454},
number = C,
volume = 159,
place = {United States},
year = {2018},
month = {8}
}

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