The Importance of Diffusivity and Partitioning Behavior of Solid Solution Strengthening Elements for the High Temperature Creep Strength of Ni-Base Superalloys

Language
en
Document Type
Article
Issue Date
2023-05-22
First published
2020-12-01
Issue Year
2020
Authors
Giese, S.
Bezold, A.
Pröbstle, M.
Heckl, A.
Neumeier, S.
Göken, M.
Editor
Publisher
Springer US
Abstract

Abstract The creep resistance of single-crystalline Ni-base superalloys at elevated temperatures depends among others on solid solution strengthening of the γ-matrix. To study the influence of various solid solution strengtheners on the mechanical properties, a series of Ni-base superalloys with the same content of different alloying elements (Ir, Mo, Re, Rh, Ru, W) or element combinations (MoW, ReMo, ReW) was investigated. Nanoindentation measurements were performed to correlate the partitioning behavior of the solid solution strengtheners with the hardness of the individual phases. The lowest γ′/γ-hardness ratio was observed for the Re-containing alloy with the strongest partitioning of Re to the γ-matrix. As a result of the creep experiments in the high-temperature/low-stress regime (1373 K (1100 °C)/140 MPa), it can be concluded that solid solution hardening in the γ-phase plays an essential role. The stronger the partitioning to the γ-phase and the lower the interdiffusion coefficient of the alloying element, the better the creep resistance. Therefore, the best creep behavior is found for alloys containing high contents of slow-diffusing elements that partition preferably to the γ-phase, particularly Re followed by W and Mo.

Journal Title
Metallurgical and Materials Transactions A
Volume
51
Issue
12
Citation
Metallurgical and Materials Transactions A 51.12 (2020): S. 6195-6206. <https://link.springer.com/article/10.1007/s11661-020-06028-0>
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