Plastic deformation mechanisms of hierarchical double contraction nanotwins in Mg

Recent experiments demonstrated that hierarchical double contraction nanotwins (DCTWs), i.e., 10 1 ¯ 1 - 10 1 ¯ 1 nanotwinned structures, can simultaneously improve the strength and ductility of Mg–Li alloys. With Mg as model material using atomistic simulations and interface defect analysis, we cha...

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Bibliographic Details
Published in:Journal of materials science 2020-09, Vol.55 (25), p.11701-11713
Main Authors: Hou, Xiao-Wei, Tang, Xiao-Zhi, Zu, Qun, Guo, Ya-Fang
Format: Article
Language:English
Subjects:
Achievement tests
Alloys
Characterization and Evaluation of Materials
Chemistry and Materials Science
Classical Mechanics
Computer simulation
Crystal defects
Crystallography and Scattering Methods
Deformation mechanisms
Grain boundaries
Materials Science
Metals & Corrosion
Plastic deformation
Polymer Sciences
Solid Mechanics
Twin boundaries
Twinning (Crystallography)
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Summary:Recent experiments demonstrated that hierarchical double contraction nanotwins (DCTWs), i.e., 10 1 ¯ 1 - 10 1 ¯ 1 nanotwinned structures, can simultaneously improve the strength and ductility of Mg–Li alloys. With Mg as model material using atomistic simulations and interface defect analysis, we characterize structural characteristics of boundaries associated with DCTWs and investigate plastic deformation mechanisms of double contraction nanotwinned structures. It is revealed that the boundaries associated with DCTWs are composed of 10 1 ¯ 1 coherent twin boundaries (CTBs), symmetrical tilt grain boundaries (STGBs), and asymmetrical tilt grain boundaries (ASTGBs). Under mechanical loadings, the corresponding grain boundary defects along STGBs and ASTGBs act as sources for nucleating and emitting basal and pyramidal dislocations, enhancing the plasticity. Meanwhile, the densely distributed CTBs in DCTWs act as strong barriers for dislocation motion, strengthening the material.
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-020-04789-y