Regensburg 2007 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 19: HV Glatzel
MM 19.1: Invited Talk
Tuesday, March 27, 2007, 14:00–14:30, H16
Development of Platinum-Based Superalloys by Optimization of Microstructure — •Uwe Glatzel — Metallische Werkstoffe, Universität Bayreuth, Ludwig-Thoma-Straße 36b, 95447 Bayreuth
Development of platinum-based superalloys was carried out by copying the successful system of nickel-base superalloys. The Pt-alloys should have a two-phase microstructure, consisting of a L12-ordered intermetallic Pt3Al phase (γ’ phase) coherently embedded in a Pt-matrix. Additionally volume fraction, lattice parameter misfit and size of the precipitates have to be optimized. In a first step composition and heat treatment was adjusted to achieve high volume fractions of cuboidal γ’ precipitates with a cube size of about 500 nm. Volume fractions of up to 50% could be obtained by ensuring a reasonable temperature window to allow homogenization heat treatment.
By a variation of the Ni-content the misfit between matrix and γ’ phase can be adjusted within the desired range of −3 · 10−3 up to −1 · 10−3.
Compression and tension creep tests were carried out. Considering low temperature ductility and testing in air, our optimized alloy results in creep resistance higher than known alloys at a temperature of 1300∘C. Additional improvements can be obtained by adding boron in small amounts. Alternatively directional solidified casting would be a promising processing route, which is currently under development.