Boosting the Thermoelectric Performance of Full-Heusler Fe ₂ VAl Alloy via Substituting Al Site with V

Full-Heusler Fe2VAl alloy has received significant attention for thermoelectric applications due to its high mechanical strength, favorable electrical transport behavior, and earth-abundant constituent elements.However, its intrinsically high lattice thermal conductivity hinders the enhancement of the figure of merit (zT).In this study, a series of bulk materials with the nominal composition of Fe2V1+xAl1-x (x=0-0.21)were prepared by the arc-melting method.The effects of substituting Al site with V on the phase composition, microstructure, band structure, and thermoelectric transport properties were systematically investigated.All materials exhibit a single phase with a partially disordered B2 structure.Vdoping shifts the Fermi level into the conduction band, significantly enhancing the carrier concentration, and resulting in a high power factor of 4.5 mWK -2 m -1 .Additionally, the lattice thermal conductivity is substantially reduced due to enhanced phonon scattering induced by the mass and stress fluctuations.Ultimately, maximum zT of 0.14 is achieved for the material with x = 0.15, which is nearly 280 times larger than that of undoped Fe2VAl.This work demonstrates that substituting Al site with V can effectively improve the thermoelectric performance of Fe2VAl alloy. Key words: Fe2VAl-based