Effects of ageing on the cyclic stability of superelasticity in [001]-oriented Ni 49 Fe 18 Ga 27 Co 6 single crystals in compression

Autor: Nikita Surikov, E. E. Timofeeva, Natalia Vetoshkina, Hans Jürgen Maier, Ksenia Osipovich, Elena Panchenko, Yuri Chumlyakov
Rok vydání: 2017
Předmět:
Zdroj: Materials Today: Proceedings. 4:4797-4801
ISSN: 2214-7853
Popis: In this study, the effects of ageing at 673 K for 4 h, resulting in the precipitation of γ´-phase particles, on the cyclic stability of superelasticity at isothermal cyclic loading (100 cycles) in [001]-oriented Ni49Fe18Ga27Co6 (at.%) single crystals in compression is experimentally established. The Ni49Fe18Ga27Co6 single crystals with B2-structure containing particles of γ-phase (5-10 μm), which are annealed at 1373 K for 25 min followed by quenching in water, undergo stress-induced B2-L10 martensitic transformation in compression. The high stress of the martensite formation, the wide stress hysteresis and the high energy dissipation result in the strong degradation of superelasticity throughout 100 loading cycles. The ageing of annealed Ni49Fe18Ga27Co6 single crystals causes the precipitation of nanosized γ΄-phase particles (measuring up to 30 nm), the change of austenite structure on L21 phase and the L21-14M stress-induced martensitic transformations, resulting in the low energy dissipation and the high cyclic stability of superelasticity.
Databáze: OpenAIRE