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MM: Fachverband Metall- und Materialphysik

MM 31: Topical Session High Temperature Materials II

MM 31.2: Topical Talk

Mittwoch, 25. März 2009, 15:15–15:45, IFW A

Atomic site location by channelling enhanced microanalysis (ALCHEMI) in gamma-prime strengthened Ni- and Pt-base alloys — Christian Liebscher, Rainer Völkl, and •Uwe Glatzel — Metallische Werkstoffe, Universität Bayreuth, D-95440 Bayreuth

The additions of alloying elements to Ni- and Pt-base alloys influence the micro structure and thereby the creep properties, whereas the mechanism is uncertain. Therefore atomic site location by channeling enhanced microanalysis (ALCHEMI) was used to determine the site partitioning of ternary and quaternary alloying elements in the L12-ordered gamma-prime phase. Two ternary Ni*Al alloys with Cr and Ti additions were investigated. The measured site partitioning showed that Cr and Ti atoms prefer the Al-sub lattice sites. For a ternary Pt*Al*Cr alloy, it was found that Cr atoms occupy Al sites. The influence of Ni as a fourth alloying element in a Pt*Al*Cr*Ni alloy on the site partitioning was also investigated. The detected results give evidence that in the quaternary alloy Cr and Ni atoms prefer the Pt sub lattice. First principles calculations were used to support the experimental data.