Materials (Sep 2023)

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

DOI
https://doi.org/10.3390/ma16186175
Journal volume & issue
Vol. 16, no. 18
p. 6175

Abstract

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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.

Keywords