Structural and superelastic properties of Fe-Mn-Al-Ni shape memory alloy sheets produced on industrial process routes by hot rolling

In the present study the structural and functional properties of Fe-Mn-Al-Ni shape memory alloy sheets produced on an industrial process route focusing on hot rolling were investigated. The as-processed condition is characterized by a high fraction of the non transforming g-phase, which ensures good workability, but is associated with poor superelasticity. The alloy shows good structural properties with a yield strength of about 600 MPa, which is well above the usual transformation stress related to the martensitic phase transformation for the investigated alloy composition. After solution annealing, a microstructure showing no preferred orientation being characterized by distinctly larger grains is present. The results obtained reveal that the previous thermo-mechanical processing had no impact on the subsequent texture, however, provided a sufficient amount of driving force for abnormal grain growth. Imposed by a cyclic heat treatment, oligocrystalline structures with grain sizes above 10 mm can be achieved in the industrially processed material, which show superelastic properties similar to material processed in small batches in the laboratory. & COPY; 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

The study investigated the structural and functional properties of Fe-Mn-Al-Ni shape memory alloy sheets produced using hot rolling. The as-processed condition showed a high fraction of the non-transforming g-phase, resulting in good workability but poor superelasticity. The alloy had good structural properties with a high yield strength of 600 MPa. Solution annealing resulted in a microstructure with no preferred orientation and larger grains. Thermo-mechanical processing had no impact on the subsequent texture but provided enough driving force for abnormal grain growth. Cyclic heat treatment achieved oligocrystalline structures with grain sizes above 10 mm, exhibiting superelastic properties similar to laboratory-processed material.