Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F16%3A00464779" target="_blank" >RIV/68081723:_____/16:00464779 - isvavai.cz</a>
Result on the web
<a href="http://dx.doi.org/10.1016/j.actamat.2016.04.005" target="_blank" >http://dx.doi.org/10.1016/j.actamat.2016.04.005</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.actamat.2016.04.005" target="_blank" >10.1016/j.actamat.2016.04.005</a>
Alternative languages
Result language
angličtina
Original language name
Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures
Original language description
Among the vast number of multi-principal-element alloys that are referred to as high-entropy alloys (HEAs) in the literature, only a limited number solidify as single-phase solid solutions. The equiatomic HEA, CrMnFeCoNi, is a face-centered cubic (FCC) prototype of this class and has attracted much attention recently because of its interesting mechanical properties. Here we evaluate its phase stability after very long anneals of 500 days at 500-900 degrees C during which it is reasonable to expect thermodynamic equilibrium to have been established. Microstructural analyses were performed using complementary analysis techniques including scanning and transmission electron microscopy (SEM/TEM/STEM), energy dispersive X-ray (EDX) spectroscopy, selected area electron diffraction (SAD), and atom probe tomography (APT). We show that the alloy is a single-phase solid solution after homogenization for 2 days at 1200 degrees C and remains in this state after a subsequent anneal at 900 degrees C for 500 days. However, it is unstable and forms second-phase precipitates at 700 and 500 degrees C. A Cr-rich sigma phase 'forms at 700 degrees C, whereas three different phases (L1(0)-NiMn, B2-FeCo and a Cr-rich body-centered cubic, BCC, phase) precipitate at 500 degrees C. These precipitates are located mostly at grain boundaries, but also form at intragranular inclusions/pores, indicative of heterogeneous nucleation. Since there is limited entropic stabilization of the solid solution state even in the extensively investigated CrMnFeCoNi alloy, the stability of other HEAs currently thought to be solid solutions should be carefully evaluated, especially if they are being considered for applications in vulnerable temperature ranges.
Czech name
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Czech description
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Classification
Type
J<sub>x</sub> - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
JG - Metallurgy, metal materials
OECD FORD branch
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Result continuities
Project
<a href="/en/project/GA14-22834S" target="_blank" >GA14-22834S: Phase Stability and Plasticity in Medium-to-High-Entropy Alloys</a><br>
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2016
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Acta Materialia
ISSN
1359-6454
e-ISSN
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Volume of the periodical
112
Issue of the periodical within the volume
JUN
Country of publishing house
GB - UNITED KINGDOM
Number of pages
13
Pages from-to
40-52
UT code for WoS article
000377326400004
EID of the result in the Scopus database
2-s2.0-84963615057