  There is an increasing reckoning that the thermoelectric performance of a
material is dependent on its microstructure. However, the
microstructure-properties relationship often remains elusive, in part due to
the complexity of the hierarchy and scales of features that influence transport
properties. Here, we focus on the promising Heusler-Fe2VAl compound. We
directly correlate microstructure and local properties, using advanced scanning
electron microscopy methods including in-situ four-point-probe technique for
electron transport measurements. The local thermal conductivity is investigated
by scanning thermal microscopy. Finally, atom probe tomography provides
near-atomic scale compositional analysis. To locally manipulate the
microstructure, we use laser surface remelting. The rapid quenching creates a
complex microstructure with a high density of dislocations and small, elongated
grains. We hence showcase that laser surface remelting can be employed to
manipulate the microstructure to reduce the thermal conductivity and electrical
resistivity, leading to a demonstrated enhancement of the thermoelectric
performance at room temperature.
