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On the Half-Heusler compounds Nb1-x{Ti,Zr,Hf}(x)FeSb: Phase relations, thermoelectric properties at low and high temperature, and mechanical properties

Autor(en)
A. Tavassoli, F. Failamani, A. Grytsiv, G. Rogl, P. Heinrich, H. Mueller, E. Bauer, M. Zehetbauer, P. Rogl
Abstrakt

A re-investigation of phase equilibria, crystal structure and homogeneity region of the Half-Heusler (HH) phase in the ternary system Nb-Fe-Sb at 600 °C has solved controversies in the literature confirming the version of Melnyk et al. ([1] J. Phase Equilibria 20 (2) (1999) 113–118). For the first time transport properties of Half-Heusler (HH) compounds NbFeSb and Nb

0.85M

0.15FeSb (M = Ti, Zr, Hf) were studied in the full temperature range from 4.2 to 823 K. The semiconducting material NbFeSb has an electronic structure close to a metal-to-insulator transition, which leads to changes of the conductivity type with the composition as well as with increasing temperature. Ti, Zr and Hf doped NbFeSb alloys show metallic behavior and were confirmed to be high ZT p-type thermoelectric materials. Surprisingly, the lattice thermal conductivity for the Zr-doped composition was found to be higher than those of the Ti- and Hf doped materials; this effect can be explained in terms of mass and strain field fluctuations. For the first time we report experimental information on thermal expansion coefficients, specific heat and elastic moduli for these p-type compounds. The mechanical properties show a good compatibility with those previously reported for n-type HH alloys.

Organisation(en)
Institut für Materialchemie, Physik Nanostrukturierter Materialien
Externe Organisation(en)
Technische Universität Wien
Journal
Acta Materialia
Band
135
Seiten
263-276
Anzahl der Seiten
14
ISSN
1359-6454
DOI
https://doi.org/10.1016/j.actamat.2017.06.011
Publikationsdatum
08-2017
Peer-reviewed
Ja
ÖFOS 2012
104011 Materialchemie, 103018 Materialphysik
Schlagwörter
ASJC Scopus Sachgebiete
Electronic, Optical and Magnetic Materials, Ceramics and Composites, Metals and Alloys, Polymers and Plastics
Link zum Portal
https://ucrisportal.univie.ac.at/de/publications/43a14cf1-671c-4411-bca9-c94df64d98b6