Abstract
Fracture in metals is controlled by material behavior around the crack tip where size-dependent plasticity, now widely demonstrated at the micron scale, should play a key role. Here, a physical origin of the controlling length scales in fracture is identified using discrete-dislocation plasticity simulations. Results clearly demonstrate that the spacing between obstacles to dislocation motion controls fracture toughness. The simulations support a continuum strain-gradient plasticity model and provide a physical interpretation for that model’s phenomenological length scale. Analysis of a dislocation pileup under a stress gradient predicts the yield stress to increase with increasing obstacle spacing, physically rationalizing the simulations.
- Received 26 May 2010
DOI:https://doi.org/10.1103/PhysRevLett.105.115502
© 2010 The American Physical Society
Synopsis
Cracking the case on fracture
Published 10 September 2010
A new model explores how the spacing between defects in materials is key to controlling their resistance to fracture.
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