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Mechanical softening of thermoelectric semiconductor Mg_2 Si from nanotwinning

Li, Guodong and An, Qi and Morozov, Sergey I. and Duan, Bo and Goddard, William A., III and Zhai, Pengcheng and Zhang, Qingjie and Snyder, G. Jeffrey (2018) Mechanical softening of thermoelectric semiconductor Mg_2 Si from nanotwinning. Scripta Materialia, 157 . pp. 90-94. ISSN 1359-6462. http://resolver.caltech.edu/CaltechAUTHORS:20180809-080526657

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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 Mg_2Si. The theoretical shear strength of nanotwinned Mg_2Si is found to be 0.93 GPa, much lower than that (6.88 GPa) of flawless Mg_2Si. Stretching the Mg-Si bond under deformation leads to the structural softening and failure of flawless Mg_2Si. While in nanotwinned Mg_2Si, the Mg-Si 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.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1016/j.scriptamat.2018.08.002DOIArticle
ORCID:
AuthorORCID
Li, Guodong0000-0002-4761-6991
An, Qi0000-0003-4838-6232
Morozov, Sergey I.0000-0001-6226-5811
Goddard, William A., III0000-0003-0097-5716
Snyder, G. Jeffrey0000-0003-1414-8682
Alternate Title:Mechanical softening of thermoelectric semiconductor Mg2 Si from nanotwinning
Additional Information:© 2018 Acta Materialia Inc. Published by Elsevier Ltd. Received 24 April 2018, Revised 13 July 2018, Accepted 1 August 2018, Available online 9 August 2018. This work is partially supported by NSF of China under No. 51772231, the 111 Project of China under Project no. B07040. Q.A. was supported by the National Science Foundation CMMI program under grant no. 1727428. S.M. was thankful for the support by Act 211 Government of the Russian Federation, under No. 02.A03.21.0011 and by the Supercomputer Simulation Laboratory of South Ural State University [26].
Funders:
Funding AgencyGrant Number
National Natural Science Foundation of China51772231
111 Project of ChinaB07040
NSFCMMI-1727428
Subject Keywords:Nanotwin-induced softening; Structure - property relation; Thermoelectric material Mg2Si; ab-initio calculation
Other Numbering System:
Other Numbering System NameOther Numbering System ID
WAG1252
Record Number:CaltechAUTHORS:20180809-080526657
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180809-080526657
Official Citation:Guodong Li, Qi An, Sergey I. Morozov, Bo Duan, William A. Goddard, Pengcheng Zhai, Qingjie Zhang, G. Jeffrey Snyder, Mechanical softening of thermoelectric semiconductor Mg2Si from nanotwinning, Scripta Materialia, Volume 157, 2018, Pages 90-94, ISSN 1359-6462, https://doi.org/10.1016/j.scriptamat.2018.08.002. (http://www.sciencedirect.com/science/article/pii/S1359646218304767)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88679
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:09 Aug 2018 16:13
Last Modified:14 Aug 2018 02:12

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