The Parametrization of Thermoelastic Martensite Phase Transformations at Constant Stress in Shape Memory Alloys Using a Sigmoidal Boltzmann Function
Orlov M.A. Fedin M.G. Kalashnikov V.S. Koledov V.V. Aksenov K.D. Nesolenov A.V. Shambilova G.K. Makarov G.I. Levin I.S.
February 2026Multidisciplinary Digital Publishing Institute (MDPI)
Metals
2026#16Issue 2
The parametrization of the thermomechanical behavior of shape memory alloys (SMAs) under constant load is described in terms of their functional properties. The deformation–temperature–stress behavior of SMAs from various alloy systems—such as Ni-Ti, Ni-Ti-Cu, and Ni-Mn-Ga—was parametrized using a sigmoidal function. This approach enables the characterization of phase transformation parameters, including transformation temperatures, kinetic parameters, and the relationship between recoverable deformation and applied stress. It is shown that the sigmoid function can serve as a universal descriptor of thermoelastic phase transformations across different alloy systems and transformation types, such as B2–R–B19′–R–B2 (Ni-Ti-Cu), B2–R–B19′–B2 (Ni-Ti), and B2 (L21)–B19′ (L20)–B2 (L21). A correlation coefficient of approximately 0.99 was achieved. The present work extends the theoretical framework of diffuse martensitic transitions in SMAs, for which the sigmoid function has been theoretically derived to describe phase fractions. The article’s novelty lies in shifting from pure mathematical approximation (curve fitting) to physical parametrization of SMA behavior specifically under constant stress (actuator mode).
martensitic transformation , parametrization , phase transformation , shape memory alloys , sigmoidal function , thermomechanical behavior , transformation temperatures
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Department of Scientific Activity, Moscow Polytechnic University, Moscow, 107023, Russian Federation
LLC Keenetica, Moscow, 115201, Russian Federation
V.A. Kotelnikov Institute of Radio Engineering and Electronics, Russian Academy of Sciences, Moscow, 125009, Russian Federation
LLC Predict Space, Novorossiysk, 353993, Russian Federation
Department of Chemistry and Chemical Technology, Kh. Dosmukhamedov Atyrau University, Studenchesky Ave., 1, Atyrau, 060011, Kazakhstan
Faculty of Chemistry, Lomonosov Moscow State University, GSP-1, 1-3 Leninskiye Gory, Moscow, 119991, Russian Federation
A.V. Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 29 Leninsky Prospect, Moscow, 119991, Russian Federation
Department of Scientific Activity
LLC Keenetica
V.A. Kotelnikov Institute of Radio Engineering and Electronics
LLC Predict Space
Department of Chemistry and Chemical Technology
Faculty of Chemistry
A.V. Topchiev Institute of Petrochemical Synthesis
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Книга Публикация научной статьи Волощук 2026 Book Publication of a scientific article 2026