Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 21: Topical Session (Symposium MM): Fundamentals of Fracture
MM 21.2: Talk
Tuesday, March 13, 2018, 10:45–11:00, TC 006
Intergranular fracture prediction via multi-scale simulations — •Bertrand Sicaud1,3, Laurent Van Brutzel2, and Maxime Sauzay1 — 1DEN- Service de Recherches Métallurgiques Appliquées (SRMA), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France — 2DEN- Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), CEA, Université Paris-Saclay, F-91191, Gif-sur-Yvette, France — 3Universités Paris-Sorbonne - UPMC, 75005 Paris, France
Observations of intergranular fracture initiation during slow strain rate tests highlight two relevant mechanisms occuring at grain boundaries (GB): stress concentrations induced by the impact of slip bands and selective internal oxidation in water environment.
The pile-up theory modeling a slip band as a slip plane of negligible thickness in a continuum elastic medium is generaly used with the Griffith criterion. However this approach leads to large underestimation of the remote stress to GB fracture.
Slip band of finite thickness (20-200 nm) inducing more realistic singularities are investigated by using crystalline finite element calculations. A new approach using quantized fracture mechanics in conjunction with a double criterion permits to deduce a model of intergranular crack initiation. This multi-scale analytical model is used with molecular dynamics results of oxide grain boundaries decohesions for assessing the oxidation embrittlement of the interface. An extensive application of the model is carried out for numerous materials. Predictions are in good agreement with experimental results.