EFFECT OF COOLING RATE ON THE SHAPE MEMORY BEHAVIOR OF Ti-54at.%Ni ALLOYS

The effects of cooling rate after aging at 550 °C for 3 h on the shape memory behavior and mechanical properties of Ti-54at.%Ni alloys are investigated in compression. It was found that it is possible to tailor the transformation temperatures of Ti-54at.%Ni alloys with cooling rate where multiple step transformation can also be observed. Shape memory behavior with transformation strain of 1 % is observed under ultra high stress level of 1500 MPa. It is also found that shape memory effect is highly stress dependent.  

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  • Shabalovskaya, S.A., Surface, corrosion and biocompatibility aspects of Nitinol as an implant material. Bio-Medical Materials and Engineering, 2002. 12(1): p. 69-109.
  • Otsuka, K. and X. Ren, Physical metallurgy of Ti–Ni-based shape memory alloys. Progress in materials science, 2005. 50(5): p. 511-678.
  • Otsuka, K. and C. Wayman, Mechanism of shape memory effect and superelasticity. Shape memory materials, 1998: p. 27-49.
  • Kurumada, M., et al., TEM study of early Ni 4 Ti 3 precipitation and R-phase in Ni-rich NiTi nanoparticles. Scripta materialia, 2004. 50(11): p. 1413-1416.
  • Hornbogen, E., Shape Memory Alloys, in Advanced Structural and Functional Materials: Proceedings of an International Seminar Organized by Deutsche Forschungsanstalt für Luft- und Raumfahrt (DLR), Köln, June 1991, W.G.J. Bunk, Editor. 1991, Springer Berlin Heidelberg: Berlin, Heidelberg. p. 133-163.
  • Prokofiev, E., et al. Phase transformations and functional properties of NiTi alloy with ultrafine-grained structure. in Materials Science Forum. 2011. Trans Tech Publ.
  • Otsuka, K., T. Sawamura, and K. Shimizu, Crystal structure and internal defects of equiatomic TiNi martensite. Physica status solidi (a), 1971. 5(2): p. 457-470.
  • Knowles, K. and D. Smith, The crystallography of the martensitic transformation in equiatomic nickel-titanium. Acta Metallurgica, 1981. 29(1): p. 101-110.
  • Carroll, M., C. Somsen, and G. Eggeler, Multiple-step martensitic transformations in Ni-rich NiTi shape memory alloys. Scripta Materialia, 2004. 50(2): p. 187-192.
  • Šittner, P., et al., In situ neutron diffraction studies of martensitic transformations in NiTi polycrystals under tension and compression stress. Materials Science and Engineering: A, 2004. 378(1–2): p. 97-104.
  • Mahesh, K., F.B. Fernandes, and R.J. Silva. Ageing effects on phase transformations in NiTi alloys. in European Symposium on Martensitic Transformations. 2009. EDP Sciences.
  • Motemani, Y., et al., Effect of cooling rate on the phase transformation behavior and mechanical properties of Ni-rich NiTi shape memory alloy. Journal of Alloys and Compounds, 2009. 469(1–2): p. 164-168.
  • Nishida, M., C. Wayman, and T. Honma, Precipitation processes in near-equiatomic TiNi shape memory alloys. Metallurgical and Materials Transactions A, 1986. 17(9): p. 1505-1515.
  • Kainuma, R., M. Matsumoto, and T. Honma, Metallographic Study of Precipitation Processes in Nickel-Rich TiNi Alloys. Bull. Res. Inst. Miner. Dressing Metall., 1987. 43(2): p. 149-158.
  • Khalil-Allafi, J. and B. Amin-Ahmadi, Multiple-step martensitic transformations in the Ni51Ti49 single crystal. Journal of materials science, 2010. 45(23): p. 6440-6445.
  • Eggeler, G., et al., On the effect of aging on martensitic transformations in Ni-rich NiTi shape memory alloys. Smart materials and structures, 2005. 14(5): p. S186.
  • Dlouhy, A., J. Khalil-Allafi, and G. Eggeler, Multiple-step martensitic transformations in Ni-rich NiTi alloys--an in-situ transmission electron microscopy investigation. Philosophical Magazine, 2003. 83(3): p. 339-363.
  • Khalil-Allafi, J., et al., Quantitative phase analysis in microstructures which display multiple step martensitic transformations in Ni-rich NiTi shape memory alloys. Materials Science and Engineering: A, 2006. 438–440(0): p. 593-596.
  • Karaca, H., et al., Shape memory behavior of high strength Ni 54 Ti 46 alloys. Materials Science and Engineering: A, 2013. 580: p. 66-70.
  • Kaya, I., et al., Effects of aging on the shape memory and superelasticity behavior of ultra-high strength Ni 54 Ti 46 alloys under compression. Materials Science and Engineering: A, 2016. 678: p. 93-100.
  • Orgéas, L. and D. Favier, Stress-induced martensitic transformation of a NiTi alloy in isothermal shear, tension and compression. Acta Materialia, 1998. 46(15): p. 5579-5591.