Structure and mechanical properties of the AlCrxNbTiV (x = 0, 0.5, 1, 1.5) high entropy alloys

Stepanov, Nikita; Yurchenko, N.; Skibin, D. V.; Tikhonovsky, М.А.; Салищев, Г. А.

doi:10.1016/j.jallcom.2015.08.224

Cited by 255 publications

(115 citation statements)

References 42 publications

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“…The Scheil simulation also predicts the formation of a single BCC phase (Figure 8f). Using the true bulk composition reported by Stepanov et al [11], the equilibration calculation predicts that the C14 Laves phase forms at T = 739-883 • C; and the solidus is 1724 • C. In fact, Stepanov et al observed the formation of a single BCC phase when homogenized at 1200 • C and the C14 Laves when annealed at 800 • C, which is in agreement with the predictions shown in Figure 8c.…”

Section: Alloyssupporting

confidence: 85%

“…On the other hand, the CALPHAD-predicted crystal structures of intermetallics that form in AlCrNbTiV, CrNbTiZr, and CrNbTiVZr during solidification also agree very well with experiments [11,13]. However, caution should be noted that the database does not cover thermodynamic descriptions for all constituent ternaries (except the Al-Cr-Ti system) of the Al-Cr-Nb-Ti-V-Zr system.…”

Section: Alloyssupporting

confidence: 60%

“…Using the true bulk composition reported in Reference [11], the equilibration calculation predicts that the C14 laves phase starts to form at 1292 • C; the solid temperature is at 1722 • C. In fact, Stepanov et al [11] observed the formation of the C14 Laves phase in the homogenized state (i.e., at 1200 • C) and for annealed states at 800 • C and 1000 • C. These results generally agree with the predictions shown in Figure 8g.…”

Section: Alloysmentioning

confidence: 99%

“…Due to the demand from transportation and defense industries, the development of a new generation of light-weight alloys has also brought widespread interest in HEAs to the materials science and engineering communities, expressly, for the purpose of saving energy and raw materials [7][8][9][10][11][12][13][14][15]. The trial-and-error approach that has been used for traditional alloys design is costly and time-consuming for the discovery of new HEAs because of the vast compositional space that they occupy.…”

Section: Introductionmentioning

confidence: 99%

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Design of Light-Weight High-Entropy Alloys

Feng

Gao

Lee

et al. 2016

Entropy

197

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High-entropy alloys (HEAs) are a new class of solid-solution alloys that have attracted worldwide attention for their outstanding properties. Owing to the demand from transportation and defense industries, light-weight HEAs have also garnered widespread interest from scientists for use as potential structural materials. Great efforts have been made to study the phase-formation rules of HEAs to accelerate and refine the discovery process. In this paper, many proposed solid-solution phase-formation rules are assessed, based on a series of known and newly-designed light-weight HEAs. The results indicate that these empirical rules work for most compositions but also fail for several alloys. Light-weight HEAs often involve the additions of Al and/or Ti in great amounts, resulting in large negative enthalpies for forming solid-solution phases and/or intermetallic compounds. Accordingly, these empirical rules need to be modified with the new experimental data. In contrast, CALPHAD (acronym of the calculation of phase diagrams) method is demonstrated to be an effective approach to predict the phase formation in HEAs as a function of composition and temperature. Future perspectives on the design of light-weight HEAs are discussed in light of CALPHAD modeling and physical metallurgy principles.

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Section: Alloyssupporting

confidence: 85%

Section: Alloyssupporting

confidence: 60%

Section: Alloysmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Design of Light-Weight High-Entropy Alloys

Feng

Gao

Lee

et al. 2016

Entropy

197

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show abstract

“…Many of the alloys also contain other elements, for example, Al [13][14][15][25][26][27][28][29][30][31][32][33]. The addition of Al has beneficial effects including: (i) reduction of density [25,27,28]; (ii) increase of strength both at room and elevated temperatures [14,25,26,28]; and (iii) increased oxidation resistance [31]. However, there is diverse information on effect of Al on phase composition of refractory HEAs: in many cases, Al stabilizes solid solution phases [25,29,31], but it can also stabilize intermetallic phases [27,32].…”

Section: Introductionmentioning

confidence: 99%

Phase Evolution of the AlxNbTiVZr (x = 0; 0.5; 1; 1.5) High Entropy Alloys

Yurchenko

Stepanov

Tikhonovsky

et al. 2016

Metals

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Al x NbTiVZr (x = 0; 0.5; 1; 1.5) high entropy alloys were fabricated by vacuum arc melting and annealed at 1200 • C for 24 h. The NbTiVZr alloy had single body centered cubic (bcc) solid solution phase after annealing at 1200 • C, while, in the Al-containing alloys, C14 Laves and Zr 2 Al-type phases are found. The alloys were subjected to annealing at 800 • C and 1000 • C. It was shown that annealing temperature (800 • C or 1000 • C) weakly affected the produced phases but the Al content had pronounced effect on structure of the annealed alloys. The NbTiVZr alloy decomposed into bcc, Zr-rich hexagonal close-packed (hcp), and C15 Laves phases. In the Al 0.5 NbTiVZr alloy, the bcc matrix phase also decomposed into a mixture of bcc and C14 Laves phases. In the AlNbTiVZr alloy, annealing resulted in an increase of volume fraction of Zr 2 Al-type phase. Finally, in the Al 1.5 NbTiVZr alloy, formation of AlNb 2 -type phase was observed. The highest fraction of second phases appeared after annealing in the NbTiVZr alloy. It is demonstrated that the strong chemical affinity and high enthalpy of formation of intermetallic phases in Al-Zr atomic pair govern the intermetallic phase formation in the alloys at 1200 • C. Increase of volume fraction of second phases in the alloys due to annealing at 800 • C and 1000 • C is in proportion to the decrease of Zr concentration in the bcc matrix phase.

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Phase Decomposition of a Single‐Phase AlTiVNb High‐Entropy Alloy after Severe Plastic Deformation and Annealing

Schuh¹,

Völker²,

Maier–Kiener³

et al. 2017

Adv Eng Mater

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An equiatomic AlTiVNb high-entropy alloy is deformed by high pressure torsion inducing a nanocrystalline microstructure. The samples then are subjected to isochronal heat treatments between 300 C and 1000 C. The hardness increase from %7.4 GPa for the as-processed state to 10.4 GPa for an annealing temperature of 700 C, while for higher temperatures the hardness starts to decrease. Furthermore, the reduced modulus increases after annealing treatments as well. It will be shown that the unusual annealing response can be related to the formation of intermetallic phases creating a multi-phase nanocomposite material during annealing. The results give new insights into the thermodynamic stability of this alloy, which are also relevant for coarser-grained microstructures.

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Structure and mechanical properties of the AlCrxNbTiV (x = 0, 0.5, 1, 1.5) high entropy alloys

Cited by 255 publications

References 42 publications

Design of Light-Weight High-Entropy Alloys

Design of Light-Weight High-Entropy Alloys

Phase Evolution of the AlxNbTiVZr (x = 0; 0.5; 1; 1.5) High Entropy Alloys

Phase Decomposition of a Single‐Phase AlTiVNb High‐Entropy Alloy after Severe Plastic Deformation and Annealing

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