Structural relaxation and self-repair behavior in nano-scaled Zr–Cu metallic glass under cyclic loading: Molecular dynamics simulations

Bulk metallic glasses are generally regarded as highly brittle materials at room temperature, with deformation localized within a few principal shear bands. In this simulation work, it is demonstrated that when the Zr–Cu metallic glass is in a small size-scale, it can deform under cyclic loading in...

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Bibliographic Details
Published in:Intermetallics 2010-05, Vol.18 (5), p.954-960
Main Authors: Lo, Y.C., Chou, H.S., Cheng, Y.T., Huang, J.C., Morris, J.R., Liaw, P.K.
Format: Article
Language:English
Subjects:
Amorphous materials
AMORPHOUS STRUCTURE
B. Fatigue resistance and crack growth
B. Glasses, metallic
B. Plastic deformation mechanisms
COMPUTER SIMULATION
Cyclic loads
CYCLIC STRESS
DEFORMATION
E. Simulations, atomistic
Fatigue (materials)
GLASS
GLASSES
MATERIALS SCIENCE
METALLIC GLASSES
MICROSTRUCTURES
Nanomaterials
Nanostructure
PLASTICS
RELAXATION
REPAIR
SHEAR
SIMULATION
THIN FILMS
Zirconium
ZIRCONIUM ALLOYS (50 TO 99 ZR)
Zirconium base alloys
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Summary:Bulk metallic glasses are generally regarded as highly brittle materials at room temperature, with deformation localized within a few principal shear bands. In this simulation work, it is demonstrated that when the Zr–Cu metallic glass is in a small size-scale, it can deform under cyclic loading in a semi-homogeneous manner without the occurrence of pronounced mature shear bands. Instead, the plastic deformation in simulated samples proceeds via the network-like shear-transition zones (STZs) by the reversible and irreversible structure-relaxations during cyclic loading. Dynamic recovery and reversible/irreversible structure rearrangements occur in the current model, along with annihilation/creation of excessive free volumes. This behavior would in-turn retard the damage growth of metallic glass. Current studies can help to understand the structural relaxation mechanism in metallic glass under loading. The results also imply that the brittle bulk metallic glasses can become ductile with the sample size being reduced. The application of metallic glasses in the form of thin film or nano pieces in micro-electro-mechanical systems (MEMS) could be promising.
ISSN:0966-9795
1879-0216
DOI:10.1016/j.intermet.2010.01.012