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Lecture

WEB Influence of high current densities on nanocrystalline FeC thin films

Friday (25.09.2020)
13:35 - 13:50 P: Processing and Synthesis 1
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Field assisted processing offers new energy-efficient paths to tune the microstructure and properties of materials. However, despite its high technological relevance, the fundamental mechanisms are not yet fully understood. The goal of our study is to identify and understand the mechanisms by which high direct current densities affect the microstructural evolution of nanocrystalline metals containing solutes. Using thin films of the model Fe(C) system, allows current densities up to several MA/cm² to be reached. The C solute atoms are moved by electromigration and cause changes in the microstructure, including causing motion of carbides that leave elongated ferrite grains in their wake [1]. Different SEM and X-ray diffraction techniques are used to observe the changes in microstructure and texture due to the treatment. We will provide detailed experimental results for this model system as well as a mechanism which can explain the observations.

Support through the DFG Priority Program (SPP 1959) “Manipulation of matter controlled by electric and magnetic fields: Towards novel synthesis and processing routes of inorganic materials” is gratefully acknowledged.

[1] Brede, T., Kirchheim, R., & Volkert, C. A. (2020). Anisotropic grain growth in iron-carbon films at high electric current densities. Scripta Materialia, 178, 18–23.

 

Speaker:
Thomas Brede
University of Göttingen
Additional Authors:
  • Prof. Cynthia Volkert
    Georg-August-Universität Göttingen
  • Prof. Dr. Reiner Kirchheim
    Georg-August-Universität Göttingen