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In situ transmission electron microscopy investigation on 〈c + a〉 slip in Mg

Published online by Cambridge University Press:  11 February 2019

Dalong Zhang Open the ORCID record for Dalong Zhang [Opens in a new window] ,
Lin Jiang ,
Xin Wang ,
Irene J. Beyerlein ,
Andrew M. Minor ,
Julie M. Schoenung ,
Subhash Mahajan  and
Enrique J. Lavernia
Dalong Zhang
Affiliation:
Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697-2575, USA
Lin Jiang
Affiliation:
Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697-2575, USA
Xin Wang
Affiliation:
Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697-2575, USA
Irene J. Beyerlein
Affiliation:
Mechanical Engineering Department, Materials Department, University of California-Santa Barbara, Santa Barbara, California 93106, USA
Andrew M. Minor
Affiliation:
Department of Materials Science and Engineering, University of California-Berkeley, and National Center for Electron Microscopy, Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
Julie M. Schoenung
Affiliation:
Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697-2575, USA
Subhash Mahajan
Affiliation:
Department of Materials Science and Engineering, University of California-Davis, Davis, California 95616, USA
Enrique J. Lavernia*
Affiliation:
Department of Chemical Engineering and Materials Science, University of California-Irvine, Irvine, California 92697-2575, USA
*
a)Address all correspondence to this author. e-mail: lavernia@uci.edu
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Abstract

Recent molecular dynamics simulations revealed that 〈c + a〉 dislocations in Mg were prone to dissociation on the basal plane, thus becoming sessile. Basal dissociation of 〈c + a〉 dislocations is significant because it is a major factor in the limited ductility and high work-hardening in Mg. We report an in situ transmission electron microscopy study of the deformation process using an H-bar-shaped thin foil of Mg single crystal designed to facilitate 〈c + a〉 slip, observe 〈c + a〉 dislocation activity, and establish the validity of the largely immobile 〈c + a〉 dislocations caused by the predicted basal dissociation. In addition, through detailed observations on the fine movement of some 〈c + a〉 dislocations, it was revealed that limited bowing out movement for some non-basal portions of 〈c + a〉 dislocations was possible; under certain circumstances, i.e., through attraction and reaction between two 〈c + a〉 dislocations on the same pyramidal plane, at least portions of the sessile configuration were observed to be reversed into a glissile one.

Keywords

Mgdislocationstransmission electron microscopy
Type
Article
Information
Journal of Materials Research , Volume 34 , Issue 9: Focus Issue: Plasticity and Fracture at the Nanoscales - Advances in in situ Experimentation Techniques Enabling Novel and Extreme Materials/Nanocomposite Design , 14 May 2019 , pp. 1499 - 1508
Copyright
Copyright © Materials Research Society 2019 

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Footnotes

b)

Now at Pacific Northwest National Laboratory.

c)

Now at Materials & Structural Analysis, Thermo Fisher Scientific, Hillsboro, OR, 97124.

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