Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 20: Topical Session Designing Innovative Structural Materials and Steels VI

MM 20.3: Vortrag

Dienstag, 23. März 2010, 12:00–12:15, H4

Ordering and precipitation in Ni-rich Ni-W and Ni-Re — •Nils Schindzielorz, Katharina Nowak, and Stefan Müller — Universität Erlangen-Nürnberg, Lehrstuhl für Theoretische Physik 2, Staudstr. 7, D-91058 Erlangen

The unusual high hardening effect of Re compared to that of W when alloying them to Ni-based superalloys has already been discussed to be caused by the formation of precipitates within the Ni matrix [1]. By the combination of a density functional theory based cluster expansion Hamiltonian with Monte-Carlo simulations using the programme package UNCLE [2] it will be shown that for Ni-Re in the dilute limit with concentrations less than 10 at. % precipitates with a D1a structure emerge within the γ phase whereas for Ni-W the dominant effect is the formation of solid solutions. The interpretation of the calculated short range order patterns clarifies these results. However, for less than 5 at. % also in Ni-W indications can be found for the formation of precipitates.
Supported by Deutsche Forschungs-Gemeinschaft.
J.Rüsing et al., Scripta Materialia 46 (2002) 235-240
D.Lerch et al., Modelling Simul. Mater. Sci. Eng 17 (2009) 055003 (19pp)