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Microstructure-Functional Behavior-Relationship in High Entropy Shape Memory Alloys

Tuesday (15.05.2018)
19:54 - 19:57
Part of:

Shape memory alloys (SMAs) show special mechanical properties and are used for many challenging applications, especially in the medical field. However, many applications are limited by the functional degradation of SMAs via plastic deformation and microstructural instability. Specifical-ly, diffusion at elevated temperatures can trigger rapid functional degradation. Recently, a high entropy alloy (HEA), was introduced by Firstov et al.. This consists, contrary to the conventional SMA, of five or more alloy components and still shows a shape memory effect. This novel class of metallic alloys, referred to as „high entropy shape memory alloy“ (HESMA) with a complex composition is a promising candidate for elevated temperature applications. However, the evolution of the functional properties of these HESMAs are still fully unexplored. Moreover, there is a need to develop reliable processing routes for melting, heat treatment, forming and shape setting for these materials.

Thus, the objective of the present study is develop a processing route for these materials and un-derstand their processing-microstructure-property-relationship. Materials will be cast and heat treat-ed and wire drawing employed to obtain samples that feature a large shape memory effect. DSC will be used to characterize the martensitic transformation temperatures. Basic functional and mechanical properties of the drawn wires as well as functional fatigue under complex thermo-mechanical loading conditions starting with compression tests will be analyzed. Particular attention will be placed on the local microstructural phenomena and the macroscopic behavior. Therefore, digital image correlation will be employed to identity and to understand the mechanisms and the areas where functional degradation is triggered in HESMAs.

The poster at “HTSMA 2018” will give an overview of the current status of research activity.

[1] G.S. Firstov, T.A. Kosorukova, Y.N. Koval, V.V. Odnosum, ICOMAT-2014 pp. 499-504

Maike Hermann
Leibniz Universität Hannover
Additional Authors:
  • David Piorunek
    Ruhr-Universität Bochum
  • Dr. Mark Alan Swider
    Leibniz Universität Hannover
  • Dr. Jan Frenzel
    Ruhr-Universität Bochum
  • Prof. Dr. Gunther Eggeler
    Ruhr-Universität Bochum
  • Prof. Dr. Hans Jürgen Maier
    Leibniz Universität Hannover