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Dresden 2014 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 34: Poster Session

MM 34.38: Poster

Tuesday, April 1, 2014, 18:00–20:00, P4

Combined experimental and theoretical study showing D1a-type local order in Ni-Re — •Sascha B. Maisel1, Nils Schindzielorz1, Alessandro Mottura2, Roger Reed3, and Stefan Müller11Institute of Advanced Ceramics, TUHH, 21073 Hamburg, Deutschland — 2School of Metallurgy and Materials, University of Birmingham, B15 2TT Edgbaston, United Kingdom — 3Department of Engineering Science, University of Oxford, OX1 3PJ Oxford, United Kingdom

Since the 1980s rhenium has been used as an addition to nickel-based high-temperature superalloys, since even small amounts of rhenium have a dramatic effect on creep resistance. However, the mechanisms behind this so-called rhenium-effect are still ill-understood. Using both experimental and theoretical methods, we show that the currently known phase diagram is inaccurate, and neglects a stoichiometric compound at 20 at.% Re Ni4Re. This is expected to affect the microstructure of Ni-Re alloys, with important ramifications for Ni-based superalloys. The Ni4Re compound is shown to be stable by means of quantum mechanical high-throughput calculations at 0K, aided by the cluster-expansion methods. Monte Carlo simulations show that it is thermally persistent up to 1100 K when considering configurational entropy. The existence of this compound was experimentally confirmed using extended x-ray absorption fine spectroscopy on a Ni.97Re.03 alloy.

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