Low lattice thermal conductivity and microstructural evolution in VFeSb half-Heusler alloys

研究成果: Article査読

5 被引用数 (Scopus)

抄録

High lattice thermal conductivity (κL) exhibited by most half-Heuslers alloys can be significantly reduced by employing nanostructuring approaches. In this work, we present the implication of nanostructuring approaches on thermoelectric transport properties of cubic VFeSb half-Heusler alloys, a prospective room temperature intermetallic that exhibits remarkably high-power factors ≈3mWm−1K−2 but undesirably high κL≈12 Wm−1K−1. The VFeSb alloys were synthesized by spark plasma sintering of powder obtained either through ball milling or melt-spinning to obtain a substantial κLreduction ∼ 50% near room temperature. The microstructure consists of nanocrystalline domains embedded in the half-Heusler matrix owing to in-situ V-segregation from the VFeSb matrix coherently along the grain boundaries. To elucidate the implications of nanostructuring on lattice-mediated phonon transport, Debye-Callaway model-based simulation was employed. Although a detrimental scattering of charge carriers was entirely averted by electron injection from in-situ formation of defects and atomic ordering, the deterioration of the Seebeck coefficient by charge compensation limited the thermoelectric figure-of-merit (zT) ≈ 0.2 at 480 K, which still corresponds to ∼50% enhancement over its bulk counterparts.

本文言語English
論文番号101430
ジャーナルMaterialia
22
DOI
出版ステータスPublished - 2022 5月

ASJC Scopus subject areas

  • 材料科学(全般)

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