Berlin 2008 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 22: HV Paxton

MM 22.1: Hauptvortrag

Dienstag, 26. Februar 2008, 14:00–14:30, H 1058

Grain boundary embrittlement and cohesion enhancement in copper — •Anthony Paxton¹, Alexander Lozovoi¹, Rainer Schweinfest², and Michael Finnis³ — ¹Atomistic Simulation Centre, Queen’s University Belfast, BT7 1NN, UK — ²Science+Computing ag, Hagellocher Weg 71-5, 720270 Tübingen, Germany — ³Imperial College London, Exhibition Road, London SW7 2AZ, UK

There has been a long standing debate surrounding the mechanism of grain boundary embrittlement and cohesion enhancement in metals. Embrittlement can lead to catastrophic failure such as happened in the Hinkley Point disaster, or indeed in the case of the Titanic! This kind of embrittlement is caused by segregation of low solubility impurities to grain boundaries. While the accepted wisdom is that this is a phenomenon driven by electronic or chemical factors, using language such as charge transfer and electronegativity difference; we believe that in copper, at least, both cohesion enhancement and reduction are caused by a simple size effect. We have developed a theory that allows us to separate unambiguously, if not uniquely, chemical and structural factors. We have studied a large number of solutes in copper using first principles atomistic simulation to support this argument, and the results of these calculations will be presented here