PSI - Issue 69

Victor Komarov et al. / Procedia Structural Integrity 69 (2025) 76–79

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of e = 0.6-3. The obtained flow curves can be used for mathematical modeling and optimization of deformation processes of NiTi alloys. 4. Summary In the present study, severe torsion deformation was applied for the first time to a bulk near-equiatomic NiTi SMA and flow curves were obtained in a temperature range of 300-600 °C. The torsional deformation at 350-600 °C and strain rate of 0.1 s -1 allows achieving high strains ( e > 3). Deformation at 350-600 °C leads to the formation of steady-state flow stress stage. The polygonized dislocation substructure can be formed in this temperature range at strains of e = 0.6 to 3. The obtained flow curves can be used for mathematical modeling and optimization of deformation processes of NiTi alloys. Acknowledgements The reported study was funded by the Russian Science Foundation (project no. 24-79-10332, https://rscf.ru/project/ 24-79-10332/). References [1] Jani, J.M., Leary, M., Subic, A., Gibson, M.A. 2019. A review of shape memory alloy research, applications and opportunities.Mater. Des., 56, 1078–1113. [2] Zareie, S., Issa, A.S., Seethaler, R.J., Zabihollah, A. 2020. Recent advances in the applications of shape memory alloys in civil infrastructures: A review. Structures, 27, 1535–1550. [3] Ryklina, E.P., Polyakova, K.A., Murygin, S.R., Isaenkova, M.G., Zaripova, M.M., Fesenko, V.A., Andreev, V.A. 2023. On Textural Heredity of Ni-rich Ti–Ni alloy: Specific Features of Transformation and Tensile Behavior. Shape Mem. Superelasticity, 9(3), 384–401. [4] Komarov, V., Karelin, R., Khmelevskaya, I., Yusupov, V., Gunderov, D. 2022. Effect of Post-Deformation Annealing on Structure and Properties of Nickel-Enriched Ti-Ni Shape Memory Alloy Deformed in Various Initially Deformation-Induced Structure States. Crystals, 12, 506. [5] Shuitcev, A., Gunderov, D.V., Sun, B., Li, L., Valiev, R.Z., Tong, Y.X. 2020. Nanostructured Ti29. 7Ni50. 3Hf20 high temperature shape memory alloy processed by high-pressure torsion. J. Mater. Sci. Technol., 52, 218–225. [6] Brailovski, V., Prokoshkin, S.D., Khmelevskaya, I.Y., Inaekyan, K.E., Demers, V., Dobatkin, S.V., Tatyanin, E.V. 2006. Structure and properties of the Ti–50.0 at% Ni alloy after strain hardening and nanocrystallizing thermomechanical processing. Mater. Trans., 47, 795–804. [7] Karelin, R.D., Khmelevskaya, I.Y., Komarov, V.S., Andreev, V.A., Perkas, M.M., Yusupov, V.S., Prokoshkin, S.D. 2021. Effect of quasi continuous equal-channel angular pressing on structure and properties of Ti-Ni shape memory alloys. J. Mater. Eng. Perform., 30, 3096–3106. [8] Khmelevskaya, I.Y., Karelin, R.D., Prokoshkin, S.D., Isaenkova, M.G., Perlovich, Y.A., Fesenko, V.A., Zaripova, M.M. 2019. Features of nanostructure and functional properties formation in Ti-Ni shape memory alloys subjected to quasi-continuous equal channel angular pressing. IOP Conf. Ser. Mater. Sci. Eng., 503, 012024. [9] Karelin, R., Komarov, V., Khmelevskaya, I., Andreev, V., Yusupov, V., Prokoshkin, S. 2023. Structure and properties of TiNi shape memory alloy after low-temperature ECAP in shells. Mater. Sci. Eng. A, 872, 144960. [10] Khmelevskaya, I., Komarov, V., Kawalla, R., Prokoshkin, S., & Korpala, G. (2017). Features of Ti-Ni alloy structure formation under multi axial quasi-continuous deformation and post-deformation annealing. Materials Today: Proceedings, 4(3), 4830-4835. [11] Valiev, R.Z., Estrin, Y., Horita, Z., Langdon, T.G., Zehetbauer, M.J., Zhu, Y. 2016. Producing bulk ultrafine-grained materials by severe plastic deformation: Ten years later. JOM, 68, 1216–1226. [12]Nakamura, K., Neishi, K., Kaneko, K. 2004. Development of Severe Torsion Straining Process for Rapid Continuous Grain Refinement. Mater. Trans., 45, 3338–3342. [13] Nakamura, K., Neishi, K., Kaneko, K. 2006. Continuous Grain Refinement Using Severe Torsion Straining Process. Mater. Sci. Forum., 503, 385–390. [14] Miyahara, Y., Emi, N., Neishi, K. 2006. Microstructures and Mechanical Properties of Mg alloy after Severe Torsion Straining Process. Mater. Sci. Forum., 503, 949–954. [15] Kawasaki, Y., Neishi, K., Miyahara, Y. 2006. Application of severe torsion straining process for grain refinement of steel.Mater. Sci. Forum., 503, 943–948. [16] Komarov, V., Khmelevskaya, I., Karelin, R., Kawalla, R., Korpala, G., Prahl, U., Yusupov, V., Prokoshkin, S. 2021. Deformation Behavior, Structure, and Properties of an Aging Ti-Ni Shape Memory Alloy after Compression Deformation in a Wide Temperature Range.JOM,73, 620–629. [17] Komarov, V., Khmelevskaya, I., Karelin, R., Postnikov, I., Korpala, G., Kawalla, R., Prokoshkin, S. 2021. Deformation behavior, structure and properties of an equiatomic Ti–Ni shape memory alloy compressed in a wide temperature range. Trans. Indian Inst. Met., 74, 2419–2426. [18] Komarov, V.; Karelin, R.; Cherkasov, V.; Yusupov, V.; Korpala, G.; Kawalla, R.; Prahl, U.; Prokoshkin, S. 2023 Effect of Severe Torsion Deformation on Structure and Properties of Titanium–Nickel Shape Memory Alloy. Metals, 13, 1099. [19] Zhou, Y., Yang, L., Huang, Y., 2013. Micro- and Macromechanical Properties of Materials. Advances in Materials Science and Engineering, 2013. p. 565.