Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 46: Invited Talk (Hauptvortrag): Roberts

MM 46.1: Invited Talk

Wednesday, March 13, 2013, 18:00–18:30, H24

Brittle-ductile transitions - cracks and dislocations — •Steve Roberts — Department of Materials, University of Oxford, OX1 3PH, UK

The interactions between loaded crack tips and dislocations are fundamental in controlling fracture behaviour and the ductile-brittle transition in simple (and some more omplex) metals, ceramics and semiconductors. Crack tips emit shielding dislocations, and can attract antishielding dislocations. These dislocations can substantially modify the crack tip stress field, leading to changes in fracture behaviour that vary with temperature via changes in dislocation nucleation and mobility. There is now a considerable body of work, both experimental and modelling, addressing these phenomena; and their combination has led to a much better understanding of the basic processes. The talk will review approaches and research in this area, and consider the new challenges and possibilities that are arising as test methods move to smaller scales and as modelling methods increase in capability, so that their usable length and time scales are now converging.