Thermodynamically Guided Improvement of Fe–Mn–Al–Ni Shape‐Memory Alloys
Alexander Walnsch, André Bauer, J. Freudenberger, Katharina Freiberg, Christina Wüstefeld, Malte Vollmer, Stephanie Lippmann, Thomas Niendorf, Andreas Leineweber, Mario J. Kriegel
Abstract
A microstructural informed thermodynamic model is utilized to tailor the pseudoelastic performance of a series of Fe-Mn-Al-Ni shape-memory alloys. Following this approach, the influence of the stability and the amount of the B2-ordered precipitates on the stability of the austenitic state and the pseudoelastic response is revealed. This is assessed by a combination of complementary nanoindentation measurements and incremental-strain tests under compressive loading. Based on these investigations, the applicability of the proposed models for the prediction of shape-memory capabilities of Fe-Mn-Al-Ni alloys is confirmed. Eventually, these thermodynamic considerations enable the guided enhancement of functional properties in this alloy system through the direct design of alloy compositions. The procedure proposed renders a significant advancement in the field of shape-memory alloys.