Microstructural Evolution and Functional Response of a FeMnSiCr Shape Memory Alloy Module Processed by High-Speed High-Pressure Torsion
- 1Interdisciplinary Research Centre in the Field of Eco-Nano Technology and Advance Materials CC-ITI, Faculty of Engineering, “Dunărea de Jos” University of Galati, 47 Domneasca Street, 800008 Galati, Romania
- 2Faculty of Materials Science and Engineering, “Gheorghe Asachi” Technical University of Iași, Bd. D. Mangeron 41, 700050 Iași, Romania
- 3National Institute for Research and Development in Microtechnologies, 023573 Bucharest, Romania
Abstract
In this study, a functional truncated-conical module made of the Fe57Mn27Si11Cr5 (at.%) shape memory alloy was investigated. The module was obtained by the severe plastic deformation process, High-Speed High-Pressure Torsion (HSHPT). It was processed in a single step, with the logarithmic strain estimated at ε = 1.10, and the correlation among the microstructure, structural state, and functional behavior was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and mechanical testing. HSHPT processing replaced the initial dendritic structure with a severely deformed and refined microstructure characterized by deformation bands, fibrous regions, and lamellar features associated with ε-martensite. XRD analysis revealed that γ-FCC austenite remained the dominant crystalline phase and that the γ(111) reflection shifted from 2θ = 43.47° to 43.12°. AFM analysis, performed over an area of 1600 µm2, revealed an arithmetic mean roughness (Ra) of 14.59 nm and a root mean square roughness (Rq) of 19.77 nm. Segmentation of the scanned area using the Flooding procedure revealed a mean Equivalent Circular Diameter (ECD) of 253.39 nm. Mechanical tests demonstrated stable functional behavior and progressive cyclic stabilization. The module exhibited a superelastic-like load–displacement response, accompanied by an increase in energy storage efficiency and a decrease in dissipated energy during repeated compression cycles.
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BibTeX
@article{stefanescu2026microstructural,
title = {{Microstructural Evolution and Functional Response of a FeMnSiCr Shape Memory Alloy Module Processed by High-Speed High-Pressure Torsion}},
author = {Cristian Stefanescu and Carmela Gurau and Daniela-Laura Buruiana and Radu Ioachim Comăneci and Cosmin Romanitan and Gheorghe Gurau},
journal = {Nanomaterials},
year = {2026},
month = oct,
doi = {10.3390/nano16211337},
url = {https://www.mdpi.com/2079-4991/16/21/1337},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Microstructural Evolution and Functional Response of a FeMnSiCr Shape Memory Alloy Module Processed by High-Speed High-Pressure Torsion
AU - Cristian Stefanescu
AU - Carmela Gurau
AU - Daniela-Laura Buruiana
AU - Radu Ioachim Comăneci
AU - Cosmin Romanitan
AU - Gheorghe Gurau
PY - 2026
DA - 2026/10/22
JO - Nanomaterials
DO - 10.3390/nano16211337
UR - https://www.mdpi.com/2079-4991/16/21/1337
AB - In this study, a functional truncated-conical module made of the Fe57Mn27Si11Cr5 (at.%) shape memory alloy was investigated. The module was obtained by the severe plastic deformation process, High-Speed High-Pressure Torsion (HSHPT). It was processed in a single step, with the logarithmic strain estimated at ε = 1.10, and the correlation among the microstructure, structural state, and functional behavior was analyzed by optical microscopy (OM), scanning electron microscopy (SEM), X-ray diffraction (XRD), atomic force microscopy (AFM), and mechanical testing. HSHPT processing replaced the initial dendritic structure with a severely deformed and refined microstructure characterized by deformation bands, fibrous regions, and lamellar features associated with ε-martensite. XRD analysis revealed that γ-FCC austenite remained the dominant crystalline phase and that the γ(111) reflection shifted from 2θ = 43.47° to 43.12°. AFM analysis, performed over an area of 1600 µm2, revealed an arithmetic mean roughness (Ra) of 14.59 nm and a root mean square roughness (Rq) of 19.77 nm. Segmentation of the scanned area using the Flooding procedure revealed a mean Equivalent Circular Diameter (ECD) of 253.39 nm. Mechanical tests demonstrated stable functional behavior and progressive cyclic stabilization. The module exhibited a superelastic-like load–displacement response, accompanied by an increase in energy storage efficiency and a decrease in dissipated energy during repeated compression cycles.
SN - 2079-4991
ER -