Cyclic Stability of Two-Way Shape Memory Effect in Aged Ni<sub>50.3</sub>Ti<sub>32.2</sub>Hf<sub>17.5</sub> Polycrystals after Various Thermomechanical Treatments
Elena Y. Panchenko,
Anton I. Tagiltsev,
Ekaterina E. Timofeeva,
Yuriy I. Chumlyakov,
Ekaterina S. Marchenko
Affiliations
Elena Y. Panchenko
Laboratory for Physics of High-Strength Crystals, Siberian Physical-Technical Institute, Tomsk State University, Lenina Str. 36, 634050 Tomsk, Russia
Anton I. Tagiltsev
Laboratory for Physics of High-Strength Crystals, Siberian Physical-Technical Institute, Tomsk State University, Lenina Str. 36, 634050 Tomsk, Russia
Ekaterina E. Timofeeva
Laboratory for Physics of High-Strength Crystals, Siberian Physical-Technical Institute, Tomsk State University, Lenina Str. 36, 634050 Tomsk, Russia
Yuriy I. Chumlyakov
Laboratory for Physics of High-Strength Crystals, Siberian Physical-Technical Institute, Tomsk State University, Lenina Str. 36, 634050 Tomsk, Russia
Ekaterina S. Marchenko
Laboratory for Physics of High-Strength Crystals, Siberian Physical-Technical Institute, Tomsk State University, Lenina Str. 36, 634050 Tomsk, Russia
In the present paper, the cyclic stability of the high-temperature two-way shape memory effect was studied in high-strength Ni50.3Ti32.2Hf17.5 polycrystals after various thermomechanical treatments—training (thermocycling under stress) and stress-induced martensite aging. The effect of training and stress-induced martensite aging on the microstructure, the two-way shape memory effect, and its cyclic stability was determined. It was found out that both thermomechanical treatments induce the high-temperature two-way shape memory effect at T > 373 K, with a strain of 1.5% in tension. The influence of cyclic tests (up to 100 stress-free cycles of cooling/heating) on the two-way shape memory effect strain, the transformation temperatures, and the microstructure was established. Different degradation mechanisms of the two-way shape memory effect were established after thermocycling and stress-induced martensite aging.
