In-situ high throughput synthesis of high-entropy alloys

doi:10.1016/j.scriptamat.2018.09.040

Scripta Materialia

Volume 160, February 2019, Pages 44-47

https://doi.org/10.1016/j.scriptamat.2018.09.040 Get rights and content

Abstract

Conventional arc-melting and casting is the most widely used synthesis method of high-entropy alloys (HEAs). However, the extremely high melting temperature and repetitious melting processes cause the evaporation of some constituent elements with a low melting temperature, resulting in inaccurateness of composition. In this work, in-situ high throughput synthesis of FeCoNiCrCuAl_x was carried out in the transmission electron microscope. The dynamic melting process of FeCoNiCrCu with Al was recorded, and the composition of FeCoNiCrCuAl_x was examined by an energy dispersive spectrometer. The in-situ high throughput method provides a novel way to prepare HEA samples efficiently.

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Acknowledgements

This work is financially supported by the National Natural Science Foundation of China [No. 11572281, 11725210 and 11672355], and the Fundamental Research Funds for the Central Universities [No. 2018XZZX001-05], and the Zhejiang Provincial Science & Technology Program of China [2017C31076].

References (21)

Y. Zhang et al.
Prog. Mater. Sci.
(2014)
L.R. Owen et al.
Acta Mater.
(2017)
D. Miracle et al.
Acta Mater.
(2017)
X.F. Wang et al.
Intermetallics
(2007)
O.N. Senkov et al.
Intermetallics
(2011)
Y.D. Wu et al.
Mater. Lett.
(2014)
Y.F. Ye et al.
Acta Mater.
(2018)
S. Guo et al.
Prog. Nat. Sci. Mater. Int.
(2011)
K.B. Zhang et al.
J. Alloys Compd.
(2009)
S. Varalakshmi et al.
Mater. Sci. Eng. A
(2010)

There are more references available in the full text version of this article.

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Ultrafine grained WC-10FeCoCu cemented carbides doped with La<inf>2</inf>O<inf>3</inf> prepared by spark plasma sintering
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Accelerated screening of Ta<inf>x</inf>(CoCrFeMnNi)<inf>1-x</inf> and Nb<inf>x</inf>(CoCrFeMnNi)<inf>1-x</inf> high-entropy alloys
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High entropy alloys are a promising group of materials with seemingly limitless and unexplored composition spaces, capable of producing extraordinary physical/mechanical properties that exceed those of conventional materials. Utilizing an additive manufacturing enabled high throughput materials discovery framework, Ta and Nb graded additions to CoCrFeMnNi are explored. Compact metallurgical Ta,Nb_x(CoCrFeMnNi)_1-x specimens spanning x = 0 – 100 at.% were fabricated by powder based directed energy deposition. Microstructure evolution as a function of specific Ta,Nb_x(CoCrFeMnNi)_1-x compositions is investigated through a combination of XRD/XRF and SEM-EDS/EBSD. Microhardness measurements were also performed to rapidly establish baseline structure–property relationships. Results revealed that eutectic microstructures were largely suppressed throughout the explored composition ranges resulting in limited ductility and extraordinary hardness.
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Citation Excerpt :
The brazed joint between the Al0.1CoCrFeNi HEA and 304 stainless steel can be used in the manufacturing of core structures, pipelines, heat exchangers, and other key parts of nuclear reactors. It has significant practical application value in the nuclear power plant and aviation industries [48,49]. Commercially available 304SS and self-prepared Al0.1CoCrFeNi HEA were employed as base materials.
In this study, an FCC + BCC dual-phase solid solution structure HEAs joint was formed during self-propagating brazing using an Al/Ni nano-multilayer. The reactive Ni/Al multilayers after ignition generates heat that is used to transform the Al/FeCo/NiCr multilayer structure into a disordered HEAs layer. The effect of external pressure on the microstructure and mechanical properties of Al_0.1CoCrFeNi/HEAF-304SS joints were first studied. During brazing, the formation of a solid solution zone was ascribed to the interdiffusion of atoms at the joint. The typical interfacial microstructure of the joint mainly includes Al-Ni-rich BCC, Co-Cr-Fe-rich FCC phases, and a minor amount of Al₅Fe₂ IMCs. With the increment of external pressure, the shear strength presented a trend of improvement, and the fracture behavior transformed from the cleavage fracture to ductile fracture. The highest shear strength of 156.8 MPa was achieved when the joints were brazed at 1050 °C for 60 min under a pressure of 40 MPa, and the joint fracture behavior was ductile. The strengthening mechanism of the joint was ascribed to the high-entropy solution strengthening mechanism in the joint. This work provides a new method for joining 304SS and HEAs, and is breaking a new ground in fabrication of HEAs-brazed joints. It is expected to be applicable in high temperature (≤800 °C) and irradiation resistant environments.
Development of cemented carbides with Co<inf>x</inf>FeNiCrCu high-entropy alloyed binder prepared by spark plasma sintering
2022, International Journal of Refractory Metals and Hard Materials
Citation Excerpt :
FCC or BCC type solid solutions are more likely to form in high-entropy alloys that are different from those of other alloys [30]. There are four core effects in high-entropy alloys: 1) High-entropy effect in thermodynamics; 2) Hysteresis diffusion effect in dynamics; 3) Lattice distortion effect on structure; 4) “Cocktail effect” in properties [27]. The special composition makes the high-entropy alloys have better fracture resistance, bending strength, corrosion and oxidation resistance, and high temperature performance than conventional alloys [27–30].
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Regular articleIn-situ high throughput synthesis of high-entropy alloys

Abstract

Graphical abstract

Section snippets

Acknowledgements

Prog. Mater. Sci.

Acta Mater.

Acta Mater.

Intermetallics

Intermetallics

Mater. Lett.

Acta Mater.

Prog. Nat. Sci. Mater. Int.

J. Alloys Compd.

Mater. Sci. Eng. A

Regular article
In-situ high throughput synthesis of high-entropy alloys