Evolution of shear bands into cracks in metallic glasses

•Observation on fracture surface after compression test of bulk metallic glasses.•A simple mathematical model successfully described the load–displacement behavior.•Planar faults or defects were found to be responsible for the crack initiation.•A new mechanism of how shear bands evolve into micro-cr...

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Bibliographic Details
Published in:Journal of alloys and compounds 2015-02, Vol.621, p.238-243
Main Authors: Zhao, Yuan-Yun, Zhang, Guangliang, Estévez, Diana, Chang, Chuntao, Wang, Xinmin, Li, Run-Wei
Format: Article
Language:English
Subjects:
Amorphous materials
Crack propagation
Deformation
Fracture mechanics
Mechanical properties
Metallic glasses
Microcracks
Shear
Shear band
Slip bands
Zirconium base alloys
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Summary:•Observation on fracture surface after compression test of bulk metallic glasses.•A simple mathematical model successfully described the load–displacement behavior.•Planar faults or defects were found to be responsible for the crack initiation.•A new mechanism of how shear bands evolve into micro-cracks was proposed. In the present work, the cracks formation and propagation behavior of a ductile Zr-based bulk metallic glass with single dominant shear band deformation was investigated. From the ideal compressive load–displacement curve of the sample with single shear band deformation, the instant at which the shear band turns into cracks and the total area of cracked-regions prior to failure were analyzed. Further investigations revealed that the micro-cracks might have originated from the local planar faults or defects within the shear plane along the shear direction. The existence of such planar faults (steps) was consistent with the observations of the surfaces of unfractured and fractured samples. Based on these results, a new interpretation of how shear bands evolve into the present micro-cracks was proposed. These novel results provide a new perspective to understand the deformation behavior of metallic glasses.
ISSN:0925-8388
1873-4669
DOI:10.1016/j.jallcom.2014.09.205