The present paper’s emphasis is on ductile BMGs. In
spite of generation of a large body of scientific literature
in the recent past on their fracture behaviour, consensus
about the micromechanisms that impart toughness to them
is still elusive. High sensitivity of fracture toughness to
composition and structural state of the alloy, and to the
experimental variables such as temperature and strain rate
are some possible reasons for this. An additional and
important reason is the high degree of variability that is
typical of the experimentally measured Kc values [9–11]
which is the focus of this paper.
Detailed experimental and computational studies by
Tandaiya et al. [12] established the following sequence of
events taking place ahead of the notch tip when a fracture
specimen of a ductile BMG is loaded: (i) plastic deformation
through extensive shear band formation and growth,which mitigates the stress concentration ahead of the tip,
(ii) initiation and stable growth of a crack inside the dominant
shear band, (iii) onset of the dynamic crack growth or
fast fracture, which results in the catastrophic fracture of
the specimen. The stable crack growth occurs due to operation
of Taylor’s fluid meniscus instability (FMI) mechanism
inside the dominant shear band.
The present paper’s emphasis is on ductile BMGs. In
spite of generation of a large body of scientific literature
in the recent past on their fracture behaviour, consensus
about the micromechanisms that impart toughness to them
is still elusive. High sensitivity of fracture toughness to
composition and structural state of the alloy, and to the
experimental variables such as temperature and strain rate
are some possible reasons for this. An additional and
important reason is the high degree of variability that is
typical of the experimentally measured Kc values [9–11]
which is the focus of this paper.
Detailed experimental and computational studies by
Tandaiya et al. [12] established the following sequence of
events taking place ahead of the notch tip when a fracture
specimen of a ductile BMG is loaded: (i) plastic deformation
through extensive shear band formation and growth,which mitigates the stress concentration ahead of the tip,
(ii) initiation and stable growth of a crack inside the dominant
shear band, (iii) onset of the dynamic crack growth or
fast fracture, which results in the catastrophic fracture of
the specimen. The stable crack growth occurs due to operation
of Taylor’s fluid meniscus instability (FMI) mechanism
inside the dominant shear band.
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