Atomistic Formation Mechanism of Multiple Shear Bands in Amorphous Metals
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- WAKEDA Masato
- Osaka Univ.
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- SHIBUTANI Yoji
- Dept. of Mech. Eng., Graduate School of Eng., Osaka Univ.
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- OGATA Shigenobu
- Dept. of Mech. Sci. and Bioengineering, Graduate School of Eng. Sci., Osaka Univ.
Bibliographic Information
- Other Title
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- アモルファス金属における多重せん断帯の原子論的形成メカニズム
- アモルファス キンゾク ニ オケル タジュウ センダンタイ ノ ゲンシロンテキ ケイセイ メカニズム
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Abstract
At room temperature, plastic deformation of amorphous metals is localized in narrow bands, so called shear bands (SBs), which is a key issue of their brittle/ductile deformations. The extremely disordered structure and the abrupt fracture obtained in the experiments hinder us from making clear the nature and dynamics of SBs. In this study, atomistic modeling to produce the multiple shear bands (MSBs), not single shear band, was proposed, and the evolution process of MSBs including their coalescence and stationary was investigated using molecular dynamics simulations. We prepared a plate of Cu-Zr binary amorphous alloy model by the melt-quench process, and then performed uniaxial tensile and compressive tests under plane stress condition. During the loading, the deformation was suddenly localized in narrow bands shortly after the onset of yielding. The propagation of SBs was accompanied with drastic stress drop and significant local heating caused by the friction of atoms. Also, critical stresses of SB nucleation considerably differed between under tension and compression. This result indicates that Tresca or von Mises criterion, commonly used as a yield condition in the crystalline metals, is not appropriate to describe the yielding of the amorphous metals. The SB angles to the loading axis are observed to be 45∼57° under tension, while 40∼46° under compression. These angles agree well with the fracture angles observed in the experiments with multi-component metallic glasses. It is concluded that the critical stress state of SB nucleation is dependent on not only the shear stress but also the stress normal to the SB, and it can be described by Mohr-Coulomb criterion.
Journal
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- Journal of the Society of Materials Science, Japan
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Journal of the Society of Materials Science, Japan 57 (2), 119-125, 2008
The Society of Materials Science, Japan
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Details 詳細情報について
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- CRID
- 1390001205418677248
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- NII Article ID
- 130002085735
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- NII Book ID
- AN00096175
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- COI
- 1:CAS:528:DC%2BD1cXjtlyqsro%3D
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- ISSN
- 18807488
- 05145163
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- NDL BIB ID
- 9394103
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- Text Lang
- ja
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- Data Source
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- JaLC
- NDL
- Crossref
- CiNii Articles
- KAKEN
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- Abstract License Flag
- Disallowed