Thermoelectric properties of half-Heusler high-entropy Ti2NiCoSn1-xSb1+ (x = 0.5, 1) alloys with VEC&gt;18

Karati, Anirudha; Hariharan, V.; Ghosh, Sanyukta; Prasad, Anil; Nagini, M.; Guruvidyathri, K.; Mallik, Ramesh Chandra; Shabadi, Rajashekhara; Bichler, Lukas; Murty, B.S.; Varadaraju, U.V.

doi:10.1016/j.scriptamat.2020.04.036

Cited by 26 publications

(26 citation statements)

References 28 publications

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“…This brought about certain reduction in the size of the secondary phases too as they are also brittle in nature (Figure S1 of supplementary data). Additionally, the BM process also helps in dissolution of certain secondary phases as has been observed in our previous reports (Ref 27,28).…”

Section: Synthesis and Consolidation Of Microcrystalline Alloys By Ba...supporting

confidence: 61%

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Karati

Ghosh

Mallik

et al. 2021

J. of Materi Eng and Perform

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Sn-doped TiFe 0.5 Ni 0.5 Sb 12x Sn x (x = 0, 0.05, 0.1, 0.2) were synthesized by vacuum arc melting (VAM). In addition to the half-Heusler phase, secondary phases of Fe-Sb-rich compound and Ti-rich compounds were obtained after VAM. The alloys were then subjected to ball milling for 1 h and 5 h. Ball milling for 1h led to microcrystalline grains, while that for 5 h led to nanocrystalline grains. Ball milling followed by spark plasma sintering (SPS) at 1173 K led to significant reduction in size of secondary phases in the microstructure. The undoped sample exhibited a ZT of 0.008 at 873 K for both 1h and 5h BM-SPS samples.

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Section: Synthesis and Consolidation Of Microcrystalline Alloys By Ba...supporting

confidence: 61%

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Karati

Ghosh

Mallik

et al. 2021

J. of Materi Eng and Perform

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“…The SEM micrographs of arc-melted samples shown in Figure S2 revealed a matrix HH phase, SnSb-rich and NiSnSbrich white phases, and a Ti-rich black phase, as observed in Ti 2 NiCoSn 0.5 Sb 1.5 . 36 Considering the isomorphous Ti−Zr phase diagram, it was observed that the Zr fraction in the HH phase increased with higher Zr content in the samples. After milling and sintering, the SnSb phase dissolves into the matrix; the white phase was found to be NiSn-rich.…”

Section: Effect Of Zr Contentmentioning

confidence: 99%

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Mishra

Tan

Trivedi

et al. 2023

ACS Appl. Energy Mater.

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The effect of doping on the thermoelectric properties of Half-Heusler (HH) high-entropy alloy (HEA) Ti2NiCoSnSb was studied. Lower thermal conductivity was observed with increased Sb doping. Mass scattering by heavy (Ta, Zr) and light (Al) dopants was studied to further lower the thermal conductivity. Dopants at the level of up to 50% at the Ti site were studied. A high HH phase content was obtained in the Zr-doped samples, and a low-lattice thermal conductivity of 1.9 W/(m·K) was observed. This value is one of the lowest reported lattice thermal conductivities in HH alloys. The poor solubility of Ta led to undissolved Ta in the samples, which enhanced the electrical properties. In the case of Al doping, the NiAl phase raised the power factor value of Ti1.8Al0.2NiCoSn0.5Sb1.5 to 2.2 × 10–3 W/(m·K2), which is almost twice the corresponding value reported for Ti2NiCoSnSb. Interestingly, a maximum ZT of 0.29 was found in all of the doped systems, although the transport mechanism and microstructure varied widely with the type of dopant. An optimum dopant level of 25% of Zr, 7.5% of Ta, and 10% of Al is necessary to obtain the maximum ZT in these alloys. Compared to HH systems, the HH high-entropy alloy (HEA) systems provide a larger composition field for tuning the transport properties by simultaneous doping of multiple elements to lower the thermal conductivity.

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“…Thermoelectric (TE) efficiency is determined by the dimensionless figure of merit (ZT = S 2 σ T /κ, where T is the absolute temperature, S is the Seebeck coefficient, σ is the electrical conductivity, and κ is the total thermal conductivity) . Several strategies have been developed in recent years to improve the ZTs of TE materials, including band engineering, , phonon engineering, − the use of energy-filter effects, , grain boundary engineering, , texture engineering, and entropy engineering, − among others. As a new alloying concept, entropy engineering displays significant potential for delivering high-performance TE materials, with (Sn, Ge, Pb, Mn)Te, − SrTiO 3 , and half-Heusler alloys (HHs) − reported in the literature.…”

Section: Introductionmentioning

confidence: 99%

“…Several strategies have been developed in recent years to improve the ZTs of TE materials, including band engineering, , phonon engineering, − the use of energy-filter effects, , grain boundary engineering, , texture engineering, and entropy engineering, − among others. As a new alloying concept, entropy engineering displays significant potential for delivering high-performance TE materials, with (Sn, Ge, Pb, Mn)Te, − SrTiO 3 , and half-Heusler alloys (HHs) − reported in the literature. Among them, HHs have recently attracted considerable attention as promising medium- and high-temperature TE materials owing to their robust high-temperature mechanical properties and excellent thermal stabilities.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Thermoelectric Properties of Zr_0.85–xHf_xNb_0.15–yTa_yCoSb Medium-Entropy Alloys: Tradeoff between “What to Alloy” and “How Much to Alloy”

et al. 2023

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Although configurational entropy is regarded to be a gene-like performance indicator for thermoelectric (TE) materials, increasing the configurational entropy alone does not guarantee a high TE figure of merit (ZT). Therefore, determining protocols for designing medium-and high-entropy TE materials with high ZT values is imperative. Herein, we provide a strategy for designing high ZT n-type ZrCoSb-based medium-entropy (ME) half-Heusler (HH) alloys and highlight the tradeoff between "what to alloy" and "how much to alloy". As expected, an intrinsically low lattice thermal conductivity of ∼2.24 W m −1 K −1 was obtained at 923 K for the Zr 0.45 Hf 0.4 Nb 0.06 Ta 0.09 CoSb ME HH alloy owing to the synergy between Zr-site disorder, anharmonicity, refined grain size, and entropy-driven multiscale defects. Entropy-driven quantum traps lead to energy-filter effects that concurrently provide optimized Seebeck coefficients and power factors. These favorable modifications enable the Zr 0.45 Hf 0.4 Nb 0.06 Ta 0.09 CoSb ME HH alloy to exhibit a high peak ZT of ∼0.57. The developed design concept provides an effective strategy for enhancing the ZT values of medium-and high-entropy TE materials.

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Thermoelectric properties of half-Heusler high-entropy Ti2NiCoSn1-xSb1+ (x = 0.5, 1) alloys with VEC>18

Cited by 26 publications

References 28 publications

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Enhanced Thermoelectric Properties of Zr_0.85–xHf_xNb_0.15–yTa_yCoSb Medium-Entropy Alloys: Tradeoff between “What to Alloy” and “How Much to Alloy”

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Thermoelectric properties of half-Heusler high-entropy Ti2NiCoSn1-xSb1+ (x = 0.5, 1) alloys with VEC>18

Cited by 26 publications

References 28 publications

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Effect of Processing Routes on the Microstructure and Thermoelectric Properties of Half-Heusler TiFe0.5Ni0.5Sb1−xSnx (x = 0, 0.05, 0.1, 0.2) Alloys

Low-Lattice Thermal Conductivity in Zr-Doped Ti2NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Enhanced Thermoelectric Properties of Zr0.85–xHfxNb0.15–yTayCoSb Medium-Entropy Alloys: Tradeoff between “What to Alloy” and “How Much to Alloy”

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Low-Lattice Thermal Conductivity in Zr-Doped Ti₂NiCoSnSb Thermoelectric Double Half-Heusler Alloys

Enhanced Thermoelectric Properties of Zr_0.85–xHf_xNb_0.15–yTa_yCoSb Medium-Entropy Alloys: Tradeoff between “What to Alloy” and “How Much to Alloy”