| Autor: |
Reddy, Gv Prasad, Robertson, Christian, depres, christophe, Fivel, Marc |
| Rok vydání: |
2013 |
| Předmět: |
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| Zdroj: |
Acta Materialia 61 (2013) 5300-5310 |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1016/j.actamat.2013.05.021 |
| Popis: |
Three-dimensional dislocation dynamics simulations are used to study micro-crack interaction with the first micro-structural barrier in face-centred cubic bi-crystals loaded in high cycle fatigue conditions. In the examined configuration, we assumed that micro-crack transmission occurs due to surface relief growth in the secondary grain ahead of the primary crack. This indirect transmission mechanism is shown to strongly depend on grain-1/grain-2 disorientation. For instance, small grain disorientation induces plastic strain localisation ahead of the crack and faster transmission through the first barrier. Conversely, large grain-1/grain-2 disorientation induces plastic strain spreading similar to crack tip blunting yielding slower indirect transmission. A semi-analytical micro-model is developed based on the present simulation results and complementary experimental observations highlighting the original notion of first-barrier compliance. The model captures well known experimental trends including effects of: grain-size, grain disorientation and micro-crack retardation at the first barrier. |
| Databáze: |
arXiv |
| Externí odkaz: |
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