Abstract
A strain-gradient crystal plasticity framework based on physical dislocation mechanisms is developed for simulation of the experimentally observed grain size effect on the low cycle fatigue of a CoCr alloy. Finite-element models of the measured microstructure are presented for both as-received and heat-treated CoCr material, with significantly different grain sizes. Candidate crystallographic slip-based parameters are implemented for prediction of fatigue crack initiation. The measured beneficial effects of fine grain size on both cyclic stress strain response and crack initiation life are predicted. The build-up of geometrically necessary dislocations as a result of strain-gradients, leading to grain-size-dependent material hardening, is shown to play a key role. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
| Original language | English (Ireland) |
|---|---|
| Pages (from-to) | 341-353 |
| Number of pages | 13 |
| Journal | Acta Materialia |
| Volume | 78 |
| DOIs | |
| Publication status | Published - 1 Oct 2014 |
Keywords
- Crystal plasticity
- Fatigue behaviour
- Finite element
- Geometrically necessary dislocations
- Size effect
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Sweeney, CA,O'Brien, B,Dunne, FPE,McHugh, PE,Leen, SB