Speaker
Description
The equiatomic CrMnFeCoNi high-entropy alloy (HEA), also named Cantor alloy, was generally considered to be a stable disordered FCC solid solution. Indeed, this alloy was reported multiple times to solidify in this state and remains so after cold forming operations and recrystallization heat treatments. However, it was later discovered that secondary phases precipitate in the Cantor alloy when subjected to long-term anneals below ~800°C [1-3]. In this contribution, different factors affecting the phase stability of the Cantor alloy and the precipitation kinetics of secondary phases, namely, chemical composition and microstructure will be presented [4]. Through a systematic characterization of the temporal evolutions of the phase fractions, the morphologies and sizes of precipitates as well as the concentration profiles forming at matrix/precipitate interfaces, we were able to identify the mechanisms and elementary diffusion processes responsible for the precipitation kinetics [5]. Based on this knowledge, the influence of the precipitation of secondary phases on tensile properties is investigated with a focus on embrittling effects. This work sheds light on the long-term stability and precipitation kinetics in the Cr-Mn-Fe-Co-Ni system but also motivates the investigation of other HEAs and compositionally complex alloys that are considered for elevated-temperature applications.
[1] B. Schuh, F. Mendez-Martin, B. Völker, E.P. George, H. Clemens, R. Pippan, A. Hohenwarter, Acta Mater. 96, 258-268 (2015).
[2] E.J. Pickering, R. Munoz-Moreno, H.J. Stone, N.G. Jones, Scripta Mater. 113, 106-109 (2016).
[3] F. Otto, A. Dlouhý, K.G. Pradeep, M. Kubenova, D. Raabe, G. Eggeler, E.P. George, Acta Mater. 112, 40-52 (2016).
[4] G. Laplanche, S. Berglund, C. Reinhart, A. Kostka, F. Fox, E.P. George, Acta Mater. 161, 338-351 (2018).
[5] G. Laplanche, Acta Mater. 199, 193-208 (2020)
| Speaker Country | Germany |
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