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Title: Phase stability and kinetics of σ-phase precipitation in CrMnFeCoNi high-entropy alloys

Abstract

Although the phase stability of high-entropy alloys in the Cr-Mn-Fe-Co-Ni system has received considerable attention recently, knowledge of their thermodynamic equilibrium states and precipitation kinetics during high-temperature exposure is limited. In the present study, an off-equiatomic Cr26Mn20Fe20Co20Ni14 high-entropy alloy was solutionized and isothermally aged at temperatures between 600 °C and 1000 °C for times to 1000 h. In the original single-phase fcc matrix, an intermetallic σ phase was found to form at all investigated temperatures. Its morphology and composition were determined and the precipitation kinetics analyzed using the Johnson-Mehl-Avrami-Kolmogorov equation and an Arrhenius type law. From these analyses, a time-temperature-transformation diagram (TTT diagram) is constructed for this off-equiatomic alloy. We combine our findings with theories of precipitation kinetics developed for traditional polycrystalline fcc alloys to calculate a TTT diagram for the equiatomic CrMnFeCoNi HEA. The results of our investigation may serve as a guide to predict precipitation kinetics in other complex alloys in the Cr-Mn-Fe-Co-Ni system.

Authors:
ORCiD logo; ; ; ; ;
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ruhr Univ., Bochum (Germany)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES); German Research Foundation (DFG)
OSTI Identifier:
1474747
Alternate Identifier(s):
OSTI ID: 1479735
Grant/Contract Number:  
AC05-00OR22725; LA 3607/1-1; GE 2736/1-1
Resource Type:
Published Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Name: Acta Materialia Journal Volume: 161 Journal Issue: C; Journal ID: ISSN 1359-6454
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; high entropy alloys; CoCrFeMnNi; microstructure; TTT diagram; Johnson–Mehl–Avrami (JMA) equation

Citation Formats

Laplanche, G., Berglund, S., Reinhart, C., Kostka, A., Fox, F., and George, E. P. Phase stability and kinetics of σ-phase precipitation in CrMnFeCoNi high-entropy alloys. United States: N. p., 2018. Web. https://doi.org/10.1016/j.actamat.2018.09.040.
Laplanche, G., Berglund, S., Reinhart, C., Kostka, A., Fox, F., & George, E. P. Phase stability and kinetics of σ-phase precipitation in CrMnFeCoNi high-entropy alloys. United States. https://doi.org/10.1016/j.actamat.2018.09.040
Laplanche, G., Berglund, S., Reinhart, C., Kostka, A., Fox, F., and George, E. P. Sat . "Phase stability and kinetics of σ-phase precipitation in CrMnFeCoNi high-entropy alloys". United States. https://doi.org/10.1016/j.actamat.2018.09.040.
@article{osti_1474747,
title = {Phase stability and kinetics of σ-phase precipitation in CrMnFeCoNi high-entropy alloys},
author = {Laplanche, G. and Berglund, S. and Reinhart, C. and Kostka, A. and Fox, F. and George, E. P.},
abstractNote = {Although the phase stability of high-entropy alloys in the Cr-Mn-Fe-Co-Ni system has received considerable attention recently, knowledge of their thermodynamic equilibrium states and precipitation kinetics during high-temperature exposure is limited. In the present study, an off-equiatomic Cr26Mn20Fe20Co20Ni14 high-entropy alloy was solutionized and isothermally aged at temperatures between 600 °C and 1000 °C for times to 1000 h. In the original single-phase fcc matrix, an intermetallic σ phase was found to form at all investigated temperatures. Its morphology and composition were determined and the precipitation kinetics analyzed using the Johnson-Mehl-Avrami-Kolmogorov equation and an Arrhenius type law. From these analyses, a time-temperature-transformation diagram (TTT diagram) is constructed for this off-equiatomic alloy. We combine our findings with theories of precipitation kinetics developed for traditional polycrystalline fcc alloys to calculate a TTT diagram for the equiatomic CrMnFeCoNi HEA. The results of our investigation may serve as a guide to predict precipitation kinetics in other complex alloys in the Cr-Mn-Fe-Co-Ni system.},
doi = {10.1016/j.actamat.2018.09.040},
journal = {Acta Materialia},
number = C,
volume = 161,
place = {United States},
year = {2018},
month = {12}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1016/j.actamat.2018.09.040

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Cited by: 14 works
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Works referencing / citing this record:

Microstructural Characterization of Mechanically Alloyed FeCoNiMnV High Entropy Alloy Consolidated by Spark Plasma Sintering
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  • Alijani, Fatemeh; Reihanian, Mohsen; Gheisari, Khalil
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Grain boundary decohesion by nanoclustering Ni and Cr separately in CrMnFeCoNi high-entropy alloys
journal, December 2019