Regensburg 2022 – wissenschaftliches Programm
KFM 13.4: Vortrag
Dienstag, 6. September 2022, 11:00–11:15, H46
Can we improve thermoelectric properties by microstructural manipulations? — •Leonie Gomell1, Tobias Haeger2, Moritz Roscher1, Hanna Bishara1, Ralf Heiderhoff2, Thomas Riedl2, Christina Scheu1, and Baptiste Gault1 — 1Max-Planck-Insitut für Eisenforschung GmbH, Düsseldorf, Deutschland — 2Institute of Electronic Devices, University of Wuppertal, Deutschland
Thermoelectric (TE) materials convert (waste) heat into electrical energy. Several material properties determine TE performance, with the influence of microstructure being the least understood. However, the microstructure plays a crucial role in the performance of TE materials.
We present microstructural investigations of Fe2VAl, synthesized via laser surface remelting. Scanning electron microscopy and atom probe tomography were used to bridge the scale from nanometer to micrometer. The local electrical resistivity was analyzed by an in-situ four-probe technique and the thermal conductivity by scanning thermal microscopy.
We observed a high dislocation density in the order of 1013 m−2 and small grains separated by low-angle grain boundaries. Segregation of V and N was found at grain boundaries and dislocations, observed by atom probe tomography. These defects scatter electrons and phonons, influencing their transport within the material.
We conclude that by manipulating the microstructure, we were able to improve the properties of Fe2VAl. The combination of detailed microstructural analysis and local measurement of properties offers the possibility of understanding the microstructure-property relationship.