Phase equilibria, mechanical properties and design of quaternary refractory high entropy alloys

Coury, Francisco Gil; Butler, T.M.; Chaput, K.J.; Saville, Alec I.; Copley, John; Foltz, John; Mason, Paul; Clarke, Kester D.; Kaufman, Michael J.; Clarke, Amy J.

doi:10.1016/j.matdes.2018.06.003

Cited by 74 publications

(18 citation statements)

References 55 publications

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“…Ingots used in Refs. [35,36] were smaller compared to that prepared in the present work, thus gaining higher cooling rate. The ingots were also annealed for homogenization and water quenched, thus metastable BCC1 solid solution was obtained.…”

Section: Alloymentioning

confidence: 53%

“…The 5 element HfNbTaTiZr alloy was studied in Refs. [35,36]. It has lower Ta + Zr content than NbTaTiZr, Nb 0.5 TaTiZr 1.5 and TaTiZr studied in the present work.…”

Section: Alloymentioning

confidence: 54%

“…The alloys containing the BCC2 phase are free of Hf. An HCP phase was predicted and confirmed experimentally in Hf containing alloys [35][36][37][38]. It means that Hf acts as an element stabilizing HCP phase.…”

Section: Alloymentioning

confidence: 64%

“…System HfNbTaTi, similar to our NbTaTiZr alloy was calculated by CAPLHAD method [36]. Also combination of BCC + HCP phases was found to be stable at room temperature the BCC2 phase appeared between 750 • C and 1000 • C.…”

Section: Ti-tamentioning

confidence: 82%

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Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Zýka

Málek

Veselý

et al. 2019

Entropy

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Refractory high entropy alloys (HEA) are promising materials for high temperature applications. This work presents investigations of the room temperature tensile mechanical properties of selected 3 and 4 elements medium entropy alloys (MEA) derived from the HfNbTaTiZr system. Tensile testing was combined with fractographic and microstructure analysis, using scanning electron microscope (SEM), wavelength dispersive spectroscope (WDS) and X-Ray powder diffraction (XRD). The 5 element HEA alloy HfNbTaTiZr exhibits the best combination of strength and elongation while 4 and 3 element MEAs have lower strength. Some of them are ductile, some of them brittle, depending on microstructure. Simultaneous presence of Ta and Zr in the alloy resulted in a significant reduction of ductility caused by reduction of the BCC phase content. Precipitation of Ta rich particles on grain boundaries reduces further the maximum elongation to failure down to zero values.Entropy 2019, 21, 114 2 of 17 Different elements are used to fabricate HEAs. Although the number of possible 4 or 5 elements combinations is enormous five basic metallic HEA groups can be distinguished: FCC HEAs based on the Cantor alloy, BCC refractory metal HEAs, light element HEAs, HCP HEAs and precious functional HEAs [7]. Ceramic HEAs have been established as well [8,9].Our attention was attracted by the refractory HEA group, which is composed of elements from IV, V and VI groups of the periodic table of elements [10]. These elements are characterized by prevailing good mutual miscibility and high melting points. The melting point of titanium (1668 • C) is the lowest among them. Therefore HEAs composed of these elements are intended for high temperature applications. Moreover some of these elements are biocompatible [11]. Therefore some of these alloys can be attractive for bioimplant related materials research. Note that β-Ti alloys used in bioimplant research are usually composed of this group of elements [12]. Several biocompatible HEAs have been already studied [13][14][15][16]. Also, hard ceramic composites were produced from the metals from IV, V and VI groups of the periodic table [17].Original definition of HEAs with single phase solid solution microstructure and good room temperature mechanical properties, especially ductility, is beneficial also for use in human medicine. Inspiration can be found also in other materials used for production of bioimplants which are used or have been used in other parts of material research, for example, TiAl6V4 in aerospace, CoCrMo in aero engines.Our first attempt in research of HEAs was therefore related to HfNbTaTiZr refractory metal alloy [18]. Our research was inspired by Senkov [19] and confirmed our expectations. Ingots produced by vacuum arc melting possessed single phase solid solution microstructure, with a high room temperature tensile strength and ductility.Some of the elements used in the HfNbTaTiZr alloy are very similar to each other with very similar chemical behaviour; Nb is chemically similar to Ta and Zr to ...

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Section: Alloymentioning

confidence: 53%

“…The 5 element HfNbTaTiZr alloy was studied in Refs. [35,36]. It has lower Ta + Zr content than NbTaTiZr, Nb 0.5 TaTiZr 1.5 and TaTiZr studied in the present work.…”

Section: Alloymentioning

confidence: 54%

Section: Alloymentioning

confidence: 64%

Section: Ti-tamentioning

confidence: 82%

See 2 more Smart Citations

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Zýka

Málek

Veselý

et al. 2019

Entropy

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“…The work combined experiments with DFT calculations to determine the balance between the surface and interfacial energies of the observed phases, which is particularly useful in elucidating the complex architectures of HEAs containing more than four phases. Since greater compositional diversity and structural complexity have been the tendency, we conclude the relationship between elements and phase numbers of HEAs based on the large numbers of reports, which is illustrated in Figure 9,13,25,63–75. It shows that the compositions of HEAs reach up to eight elements, and the number of phases achieves four.…”

Section: Phase Structure Of Heasmentioning

confidence: 84%

Phase Engineering of High‐Entropy Alloys

et al. 2020

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High‐entropy alloys (HEAs) are based on five or more principal elements with equal or nearly equal molar fractions and possess many significant advantages over traditional alloys, including high strength and hardness, excellent corrosion resistance, outstanding thermal stability, and irradiation resistance. Phase structure plays a vital role in determining the property of HEAs. For further enhancing the performance of HEAs in various application fields, a controllable synthesis with desired phases is required. In this review, the diverse phase structures of HEAs and the related properties are first introduced. Then, alternative tuning strategies to promote the desired phase structure of HEAs are focused upon. Property adjusting of phase‐engineered HEAs is also discussed in depth. Lastly, some insights into the challenges and future prospects in this rapidly emerging research field are provided.

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A Personal Perspective on the Discovery and Significance of Multicomponent High-Entropy Alloys

Cantor

2021

High-Entropy Materials: Theory, Experiments, and Applications

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Phase equilibria, mechanical properties and design of quaternary refractory high entropy alloys

Cited by 74 publications

References 55 publications

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Microstructure and Room Temperature Mechanical Properties of Different 3 and 4 Element Medium Entropy Alloys from HfNbTaTiZr System

Phase Engineering of High‐Entropy Alloys

A Personal Perspective on the Discovery and Significance of Multicomponent High-Entropy Alloys

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