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Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C

Epishin, Alexander I. and Fedelich, Bernard and Viguier, Bernard and Schriever, Sina and Svetlov, Igor L. and Petrushin, Nikolay V. and Saillard, Romain and Proietti, Arnaud and Poquillon, Dominique and Chyrkin, Anton Creep of single-crystals of nickel-base γ-alloy at temperatures between 1150 °C and 1288 °C. (2021) Materials Science and Engineering A, 825. 141880. ISSN 0921-5093

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Official URL: https://doi.org/10.1016/j.msea.2021.141880

Abstract

A γ-analogue of the superalloy CMSX-4 that does not contain the strengthening γ′-phase and only consists of the γ-solid solution of nickel has been designed, solidified as single-crystals of different orientations, and tested under creep conditions in the temperature range between 1150 and 1288 °C. The tests have revealed a very high creep anisotropy of this alloy, as was previously found for CMSX-4 at supersolvus temperature of 1288 °C. This creep anisotropy could be explained by the dominance of 011111 octahedral slip. Furthermore, the analysis of the creep data has yielded a high value of the creep activation energy, Qc≈442 kJ/mol, which correlates with the high activation energy of Re diffusion in Ni. This supports the hypothesis that dislocation motion in the γ-matrix of Re-containing superalloys is controlled by the diffusion of the Re atoms segregating at the dislocation core. The Norton stress exponent n is close to 5, which is a typical value for pure metals and their alloys. The absence of γ′-reprecipitation after high-temperature creep tests facilitates microstructural investigations. It has been shown by EBSD that creep deformation results in an increasing misorientation of the existing low angle boundaries. In addition, according to TEM, new low angle boundaries appear due to reactions of the a/2011 mobile dislocations and knitting of new networks.

Item Type:Article
HAL Id:hal-03416184
Audience (journal):International peer-reviewed journal
Uncontrolled Keywords:
Institution:Other partners > Federal Institute for Materials Research and Testing - BAM (GERMANY)
French research institutions > Centre National de la Recherche Scientifique - CNRS (FRANCE)
Université de Toulouse > Institut National Polytechnique de Toulouse - Toulouse INP (FRANCE)
Other partners > Moscow State Aviation Institute (RUSSIA)
Other partners > Technische Universität Berlin - TU Berlin (GERMANY)
Université de Toulouse > Université Toulouse III - Paul Sabatier - UT3 (FRANCE)
Other partners > Chalmers University of Technology (SWEDEN)
Laboratory name:
Funders:
Agence Nationale de la Recherche - ANR - German Research Foundation DFG - Russian Foun-dation of Basic research
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Deposited On:05 Nov 2021 09:18

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