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Title: Formation and stability of long basal-prismatic facets in Mg

Abstract

Long BP facets bounding {101¯2} 1¯011 twins in Mg ( ≥ 4nm) have been observed experimentally. However, the formation of these long BP facets has not been studied and their contribution/role to the twin growth remains unclear. We observed a long straight BP facet (27 nm) using high-resolution transmission electron microscopy (HRTEM) and investigated its formation, stability, and mobility by atomistic simulations. Experimentally, a serrated twin interface containing short CTBs and short BP facets near a (101¯2) twin tip is observed to transform under the effects of the electron beam into a long straight semi-coherent BP facet that contains disclination dipoles. Molecular dynamics (MD) simulations of the relaxation of a 3D twin domain reveals another process whereby a long partially-relaxed BP interface forms and contains an I 2 stacking fault. A comparison between the energy of these configurations as obtained by atomistic simulations suggests that these transformations occur in two steps: (1) serrated interfaces composed of coherent BP segments with lengths less than 2 nm combine and form a long and straight coherent BP facets and (2) these long coherent BP facets quickly transform into relaxed ones with misfit defects. Importantly, it is found that long BP facets are relativelymore » immobile, and upon reloading, decay into more mobile serrated interfaces prior to migrating. Here, the work presented suggests that the atomistic configurations of BP facets during twin growth processes differ significantly from relaxed BP interfaces that would be observed by TEM.« less

Authors:
ORCiD logo [1];  [1];  [2]; ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [1]
  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  2. Univ. of Nebraska-Lincoln, Lincoln, NE (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE Office of Science (SC). Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1578027
Report Number(s):
LA-UR-19-28873
Journal ID: ISSN 1359-6454
Grant/Contract Number:  
89233218CNA000001
Resource Type:
Accepted Manuscript
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Name: Acta Materialia; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
Twinning; Basal Prismatic Interface; Molecular Dynamics; HRTEM

Citation Formats

Dang, Khanh Quoc, Wang, Shujuan, Gong, Mingyu, McCabe, Rodney James, Wang, Jian, and Capolungo, Laurent. Formation and stability of long basal-prismatic facets in Mg. United States: N. p., 2019. Web. doi:10.1016/j.actamat.2019.11.070.
Dang, Khanh Quoc, Wang, Shujuan, Gong, Mingyu, McCabe, Rodney James, Wang, Jian, & Capolungo, Laurent. Formation and stability of long basal-prismatic facets in Mg. United States. doi:10.1016/j.actamat.2019.11.070.
Dang, Khanh Quoc, Wang, Shujuan, Gong, Mingyu, McCabe, Rodney James, Wang, Jian, and Capolungo, Laurent. Tue . "Formation and stability of long basal-prismatic facets in Mg". United States. doi:10.1016/j.actamat.2019.11.070.
@article{osti_1578027,
title = {Formation and stability of long basal-prismatic facets in Mg},
author = {Dang, Khanh Quoc and Wang, Shujuan and Gong, Mingyu and McCabe, Rodney James and Wang, Jian and Capolungo, Laurent},
abstractNote = {Long BP facets bounding {101¯2} 1¯011 twins in Mg ( ≥ 4nm) have been observed experimentally. However, the formation of these long BP facets has not been studied and their contribution/role to the twin growth remains unclear. We observed a long straight BP facet (27 nm) using high-resolution transmission electron microscopy (HRTEM) and investigated its formation, stability, and mobility by atomistic simulations. Experimentally, a serrated twin interface containing short CTBs and short BP facets near a (101¯2) twin tip is observed to transform under the effects of the electron beam into a long straight semi-coherent BP facet that contains disclination dipoles. Molecular dynamics (MD) simulations of the relaxation of a 3D twin domain reveals another process whereby a long partially-relaxed BP interface forms and contains an I2 stacking fault. A comparison between the energy of these configurations as obtained by atomistic simulations suggests that these transformations occur in two steps: (1) serrated interfaces composed of coherent BP segments with lengths less than 2 nm combine and form a long and straight coherent BP facets and (2) these long coherent BP facets quickly transform into relaxed ones with misfit defects. Importantly, it is found that long BP facets are relatively immobile, and upon reloading, decay into more mobile serrated interfaces prior to migrating. Here, the work presented suggests that the atomistic configurations of BP facets during twin growth processes differ significantly from relaxed BP interfaces that would be observed by TEM.},
doi = {10.1016/j.actamat.2019.11.070},
journal = {Acta Materialia},
number = ,
volume = ,
place = {United States},
year = {2019},
month = {12}
}

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This content will become publicly available on December 3, 2020
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