Mechanical softening of thermoelectric semiconductor Mg2Si from nanotwinning
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Authors
Li, Guodong
An, Qi
Morozov, Sergey I.
Duan, Bo
Goddard III, William A.
Zhai, Pengcheng
Zhang, Qingjie
Snyder, G. Jeffrey
Issue Date
2018
Type
Citation
Language
Keywords
Nanotwin-induced softening , Structure-property relation , Thermoelectric material Mg2Si , ab-initio calculation
Alternative Title
Abstract
Nanotwinning exhibits strengthening effects in many metals, semiconductors, and ceramics. However, we show from ab-initio calculations that nanotwins significantly decrease the strength of thermoelectric semiconductor Mg2Si. The theoretical shear strength of nanotwinned Mg2Si is found to be 0.93 GPa, much lower than that (6.88 GPa) of flawless Mg2Si. Stretching the MgSi bond under deformation leads to the structural softening and failure of flawless Mg2Si. While in nanotwinned Mg2Si, the MgSi bond at the twin boundary (TB) is expanded to accommodate the structural misfit, weakening the TB rigidity and leading to the low ideal shear strength.
Description
Citation
Publisher
Elsevier
License
In Copyright
Journal
Volume
Issue
PubMed ID
ISSN
1359-6462