Thermoelectric properties of a high entropy half-Heusler alloy processed by a fast powder metallurgy route

Karati, Anirudha; Mishra, Soumya Ranjan; Ghosh, Sanyukta; Mallik, Ramesh Chandra; Shabadi, Rajashekhara; Ramanujan, R.V.; Yadav, Satyesh Kumar; Murty, B.S.; Varadaraju, U.V.

doi:10.1016/j.jallcom.2022.166108

Cited by 12 publications

(11 citation statements)

References 45 publications

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“…The parameters chosen were based on the DFT study done for the Ti 2 NiCoSnSb sample. 35 The first-principles investigation revealed very similar lattice parameters (HH phase) to that observed from XRD in the Zr-doped and undoped Ti 2 NiCoSn 0.5 Sb 1.5 samples with higher HH phase content (Table 1). The increased Zr fraction in the HH matrix expands the lattice, as can be seen through an increase in the lattice parameter values.…”

Section: Analysis Of Transport Properties Employing First Principlessupporting

confidence: 58%

“…And the band structure 7 Nanostructuring was also attempted to enhance the ZT in Ti 2 NiCoSnSb. 35 In the present study, heavy-element Zr and Ta doping were performed in Ti 2 NiCoSn 0.5 Sb 1.5 to lower the thermal conductivity. Also, considering the increase in ZT in Ti 2 NiCoSn 0.5 Sb 1.5 compared to Ti 2 NiCoSnSb, 36 the effect of varying the Sn content in TiZrNiCoSn x Sb 2−x was studied.…”

Section: T H Imentioning

confidence: 99%

“…The fraction of this phase was found to vary with processing conditions. 35 Other processing routes like rapid solidification, mechanical alloying, etc. can result in different microstructures and transport properties in these alloys.…”

Section: Analysis Of Transport Properties Employing First Principlesmentioning

confidence: 99%

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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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Section: Analysis Of Transport Properties Employing First Principlessupporting

confidence: 58%

Section: T H Imentioning

confidence: 99%

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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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“…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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Integrated First Principles and Experimental Investigation of Thermoelectric Transport in Zr/Ti Half‐Heusler‐Type High Entropy Alloys

Adamo,

Srivastava,

Legese

et al. 2024

Energy Tech

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A novel high‐entropy alloy based on zirconium (Zr) and titanium (Ti) within the half‐Heusler (hH) system is successfully synthesized via arc melting followed by heat treatment. Structural and microstructural analyses are conducted utilizing scanning electron microscopy, electron probe microanalysis, and X‐Ray diffractometry, revealing a cubic hH structure (F4¯3m). Investigation of the thermoelectric transport properties across a temperature range from room temperature to 973 K is indicated by favorable thermoelectric figure of merit values at elevated temperature regimes. Remarkably, the experimental thermal data exhibit excellent agreement with density functional theory calculations about phonon dispersion, phonon group velocity, and Grüneisen parameters, elucidating the role of crystal distortion‐induced anharmonicity in retarding phonon heat transport, thereby enhancing its suitability for thermoelectric applications.

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Thermoelectric properties of a high entropy half-Heusler alloy processed by a fast powder metallurgy route

Cited by 12 publications

References 45 publications

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

Integrated First Principles and Experimental Investigation of Thermoelectric Transport in Zr/Ti Half‐Heusler‐Type High Entropy Alloys

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Thermoelectric properties of a high entropy half-Heusler alloy processed by a fast powder metallurgy route

Cited by 12 publications

References 45 publications

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

Integrated First Principles and Experimental Investigation of Thermoelectric Transport in Zr/Ti Half‐Heusler‐Type High Entropy Alloys

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