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Crack-tip strain field mapping and the toughness of metallic glasses
- Source :
- PLoS ONE, Vol 8, Iss 12, p e83289 (2013), PLoS ONE
- Publication Year :
- 2013
- Publisher :
- Public Library of Science (PLoS), 2013.
-
Abstract
- We have used high-energy x-ray scattering to map the strain fields around crack tips in fracture specimens of a bulk metallic glass under load at room temperature and below. From the measured strain fields we can calculate the components of the stress tensor as a function of position and determine the size and shape of the plastic process zone around the crack tip. Specimens tested at room temperature develop substantial plastic zones and achieve high stress intensities ((K(If) = 76 MPa m(1/2)) prior to fracture. Specimens tested at cryogenic temperatures fail at reduced but still substantial stress intensities (K(If) = 39 MPa m(1/2)) and show only limited evidence of crack-tip plasticity. We propose that the difference in behavior is associated with changes in the flow stress and elastic constants, which influence the number density of shear bands in the plastic zone and thus the strain required to initiate fracture on an individual band. A secondary effect is a change in the triaxial state of stress around the crack tip due to the temperature dependence of Poisson's ratio. It is likely that this ability to map elastic strains on the microscale will be useful in other contexts, although interpreting shifts in the position of the scattering peaks in amorphous materials in terms of elastic strains must be done with caution.
- Subjects :
- Surface Properties
Materials Science
Material Properties
Geometry
Computational Geometry
lcsh:Medicine
02 engineering and technology
Glass Science
Flow stress
Plasticity
01 natural sciences
Stress (mechanics)
Crack closure
Fracture toughness
Materials Physics
Materials Testing
0103 physical sciences
Mechanical Properties
Composite material
lcsh:Science
Biology
Stress intensity factor
Differential Geometry
010302 applied physics
Physics
Multidisciplinary
Vitreous Materials
Cauchy stress tensor
Electromagnetic Radiation
X-Rays
lcsh:R
Physical Metallurgy
Computational Biology
Fracture mechanics
021001 nanoscience & nanotechnology
Elasticity
Chemistry
Metals
Metallurgy
Biophysic Al Simulations
lcsh:Q
Glass
Stress, Mechanical
Material by Structure
Shear Strength
0210 nano-technology
Mathematics
Research Article
Subjects
Details
- Language :
- English
- ISSN :
- 19326203
- Volume :
- 8
- Issue :
- 12
- Database :
- OpenAIRE
- Journal :
- PLoS ONE
- Accession number :
- edsair.doi.dedup.....617c0b60478836ebe9406ab8a6c8dbab