Extended ductility due to kink band formation and growth under tensile loading in single crystals of Mg-Zn-Y alloy with 18R-LPSO structure

JOURNAL OF ALLOYS AND COMPOUNDS

卷:806

Article

Takagi, Kosuke¹  Mayama, Tsuyoshi¹  Mine, Yoji¹  Chiu, Yu Lung²  Takashima, Kazuki¹ 

[1] Kumamoto Univ, Dept Mat Sci & Engn, Chuo Ku, 2-39-1 Kurokami, Kumamoto 8608555, Japan

[2] Univ Birmingham, Sch Met & Mat, Birmingham B15 2TT, W Midlands, England

关键词: Mechanical properties;    Anisotropy;    Intermetallics;    Metals and alloys;    Dislocations and disclinations;    Transmission electron microscopy;    TEM;   

DOI  :  10.1016/j.jallcom.2019.07.344

来源: Elsevier

【 摘 要 】

The deformation behaviour of single crystals of an Mg85Zn6Y9 alloy with an 18R-LPSO structure was experimentally and numerically investigated using a micro-tensile testing method and a crystal plasticity finite element method, respectively. The deformation microstructure was characterised using optical and electron microscopy. The experimental results indicated that kink band was formed in the specimens depending on the initial crystal orientation relative to the loading direction. The kink banding was accompanied with remarkable ductility of over 50% nominal strain. The deformation behaviour observed was successfully reproduced in a crystal plasticity finite element analysis. The numerical results indicated that the kink band was formed by the accumulation of basal slip, which was enhanced by the geometrical softening owing to the lattice rotation. The growth of a kink band, which was reasonably explained by the changes in Schmid factor for a basal slip system due to lattice rotation, suppressed the localised failure at low strain. This resulted in the observed extended ductility, even in the LPSO structure with strong plastic anisotropy. (C) 2019 Elsevier B.V. All rights reserved.

【 授权许可】

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