Microstructure manipulation by laser-surface remelting of a full-Heusler compound to enhance thermoelectric properties

Leonie Gomell*, Tobias Haeger, Moritz Roscher, Hanna Bishara, Ralf Heiderhoff, Thomas Riedl, Christina Scheu, Baptiste Gault

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

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 Heusler-Fe2VAl compound, which shows promising thermoelectric properties, is non-toxic, cheap, and consist of earth-abundant elements. 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.

Original languageEnglish
Article number117501
JournalActa Materialia
Volume223
DOIs
StatePublished - 15 Jan 2022
Externally publishedYes

Keywords

  • Atom Probe Tomography
  • Heusler-Alloys
  • Laser Surface Remelting
  • Microstructure
  • thermoelectric materials

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