Chemical segregation and precipitation at anti-phase boundaries in thermoelectric Heusler-Fe2VAl.

Fe 2 VAl exhibits promising properties for thermoelectric applications. Here, we investigated the microstructure of melt spun Fe 2 VAl using electron microscopy, atom probe tomography and field ion microscopy. We observe platelet-shaped VC x N y precipitates in the vicinity of antiphase boundaries (APB) oriented along the {100}-plane. The mean distance between these precipitates is (140 ± 40) nm. This distance is shorter than the mean free phonon path at room temperature in Fe 2 VAl. Thus, these VC x N y precipitates, combined with the APB may efficiently lower the thermal conductivity of the alloy. Image, graphical abstract [ABSTRACT FROM AUTHOR]