An instability index of shear band for plasticity in metallic glasses
Catastrophic failure along a dominant shear band sets the limit on how much plasticity can be achieved in metallic glasses (MGs) under uniaxial compression. Here we show that this instability process is governed by a single system parameter, called the shear-band instability index (SBI), which is pr...
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Veröffentlicht in: | Acta materialia 2009-03, Vol.57 (5), p.1367-1372 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Catastrophic failure along a dominant shear band sets the limit on how much plasticity can be achieved in metallic glasses (MGs) under uniaxial compression. Here we show that this instability process is governed by a single system parameter, called the shear-band instability index (SBI), which is proportional to sample size and inversely proportional to machine stiffness. We provide extensive experimental proof of this concept by conducting a series of tests with a range of controlled values of sample size and machine stiffness. The theory of SBI has led us to a more comprehensive understanding of the mechanisms of plastic deformation in MGs via simultaneous operation of multiple shear bands versus a single dominant one. This concept provides a theoretical basis to design systems which promote plasticity/ductility in MGs by suppressing or delaying shear-band instability. |
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ISSN: | 1359-6454 1873-2453 |
DOI: | 10.1016/j.actamat.2008.11.018 |