On the influence of Mn on the phase stability of the CrMnxFeCoNi high entropy alloys

Christofidou, Katerina A.; Pickering, Ed; Orsatti, P; Mignanelli, P. M.; Slater, Thomas J. A.; Stone, Howard J.; Jones, Nicholas

doi:10.1016/j.intermet.2017.09.011

Cited by 78 publications

(32 citation statements)

References 29 publications

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“…CALPHAD calculations have shown an expansion of the phase field with increasing concentration of Mn as well as an increase in the phase solvus temperature. Experimental studies of CrMnFeCoNi with varying Mn contents examined at temperatures between 500 C validated these general trends, but found that the phase stability was under predicted by the thermodynamic models [8,11].…”

Section: Introductionmentioning

confidence: 83%

“…E C tetragonal (L10) NiMn phase, an ordered B2 FeCo phase, as well as the precipitation of a second solid solution phase based on Cr with a bcc (A2) structure [3,4]. Furthermore, the formation of carbides and ceramic inclusions has also been reported at various temperatures, which are believed to be a result of impurities incorporated into the material during processing [2,11,12].…”

Section: Introductionmentioning

confidence: 99%

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On the prediction and the formation of the sigma phase in CrMnCoFeNix high entropy alloys

Christofidou

McAuliffe

Mignanelli

et al. 2019

Journal of Alloys and Compounds

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The almost limitless variations in potential compositions of high entropy alloys necessitates the use of computational methods when attempting to optimise for any given application. However, the accuracy of the current thermodynamic approaches commonly being used for this purpose remains under debate, as relatively few validatory studies have been performed. Within the CrMnFeCoNi family of alloys, the formation of the phase and how it is influenced by compositional variations is of particular interest for elevated temperature structural applications. Here, the role of Ni on the formation of the phase has been studied through a systematic series of CrMnFeCoNix alloys, 0 x 1.5, following 1000 hour exposures at temperatures typically found to promote formation. Ni was found to have a significant effect on the phase stability of these alloys, suppressing the phase such that a single solid solution phase was the only stable phase in the CrMnFeCoNi1.5 alloy, whilst the CrMnFeCo alloy formed the phase during solidification. The corresponding thermodynamic predictions varied dramatically from the experimentally observed microstructures, indicating that the underlying databases require further optimisation. Interestingly, it was found that a relatively simple electronic structure based approach, New PhaComp, provided much more accurate predictions of the observed phase formation in the CrMnFeCoNix and CrMnxFeCoNi systems and could be manipulated to obtain formation temperatures. As such, this method could be extremely useful to those wanting to design CrMnFeCoNi high entropy alloys that are free from the phase.

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Section: Introductionmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

On the prediction and the formation of the sigma phase in CrMnCoFeNix high entropy alloys

Christofidou

McAuliffe

Mignanelli

et al. 2019

Journal of Alloys and Compounds

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“…However, the universality of occurrence of the abovementioned core effects in HEAs is debatable [4][5][6][7][8][9]. For instance, the very theory describing entropic stabilization has found little experimental validation, indicated by the fact that majority of HEAs that have fabricated till now either exist as multiphase alloys or decompose to more than one phase at thermodynamic equilibrium [6][7][8][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

High Entropy Alloys: Ready to Set Sail?

Basu

Hosson

2020

Metals

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Over the past decade, high entropy alloys (HEAs) have transcended the frontiers of material development in terms of their unprecedented structural and functional properties compared to their counterpart conventional alloys. The possibility to explore a vast compositional space further renders this area of research extremely promising in the near future for discovering society-changing materials. The introduction of HEAs has also brought forth a paradigm shift in the existing knowledge about material design and development. It is in this regard that a fundamental understanding of the metal physics of these alloys is critical in propelling mechanism-based HEA design. The current paper highlights some of the critical viewpoints that need greater attention in the future with respect to designing mechanically and functionally advanced materials. In particular, the interplay of large compositional gradients and defect topologies in these alloys and their corresponding impact on overall mechanical response are highlighted. From the point of view of functional response, such chemistry vis-à-vis topology correlations are extended to novel class of nano-porous HEAs that beat thermal coarsening effects despite a high surface to volume ratio owing to retarded diffusion kinetics. Recommendations on material design with regards to their potential use in diverse applications such as energy storage, actuators, and as piezoelectrics are additionally considered.

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“…Сплавы, с составом CoCrFeNi (CCFN), являются одними из наиболее изученных ВЭС. Фазовый состав CCFN был исследован с помощью рентгеноструктурного анализа (XRD) [27] и энергодисперсионным рентгеновским методом (EDX) [28], нейтронографическим исследованием [29] и высокоугловой темнопольной просвечивающей микроскопией (HAADF) [30]. В большинстве работ было продемонстрировано, что CCFN образует однофазный твердый раствор [31,14,32,27].…”

Section: Introductionunclassified

“…Например, высокоэнергетический XRD-анализ показал наличие двух решеток FCC с близкими значениями постоянных решетки [29]. Кроме того, анализ HAADF и EDX показали образование преципитатов из атомов Cr [28] и локальное упорядочение Cr [30]. Также было обнаружено образование хром-насыщенных предвыделений с ОЦК и тетрагональной кристаллической решеткой [33].…”

Section: Introductionunclassified

Экспериментально-теоретическое исследование эволюции атомной структуры высокоэнтропийных сплавов на основе Fe, Cr, Ni, Mn и Co при термическом и радиационном старении

Мешков¹,

Новоселов²,

Янилкин³

et al. 2020

Физика Твердого Тела

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The comprehensive experimental and theoretical study of the processes of local ordering of multicomponent alloys was carried out. Experimental techniques included atom-probe tomography and measurement of electrical resistivity during isochronal annealing. The theoretical study was carried out by atomistic modeling methods. The evolution of the system was described in the framework of the multiscale paradigm which is based on quantum-mechanical calculations. The initial stage of the decomposition of a solid solution of CoCrFeNi alloy with the formation of Ni4Cr and Ni2Cr precipitations was demonstrated for the first time by the employed approach.

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On the influence of Mn on the phase stability of the CrMnxFeCoNi high entropy alloys

Cited by 78 publications

References 29 publications

On the prediction and the formation of the sigma phase in CrMnCoFeNix high entropy alloys

On the prediction and the formation of the sigma phase in CrMnCoFeNix high entropy alloys

High Entropy Alloys: Ready to Set Sail?

Экспериментально-теоретическое исследование эволюции атомной структуры высокоэнтропийных сплавов на основе Fe, Cr, Ni, Mn и Co при термическом и радиационном старении

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