Cyclic stability of superelasticity in the aged [${\bar{1}}23$]-oriented Ni₄₉Fe₁₈Ga₂₇Co₆ single crystals

The results of investigation of the effect of precipitates of different sizes, from 5 to 300 nm, on the character of stress-induced martensitic transformations, the value of stress hysteresis and cyclic stability of superelasticity in Ni₄₉Fe₁₈Ga₂₇Со₆ (at.%) ferromagnetic single crystals oriented along the [${\bar{1}}23$] axis are presented. It is shown that a martensitic transformation in single crystals of Ni₄₉Fe₁₈Ga₂₇Со₆ containing dispersed particles of the γ- and γ'-phases measuring up to 30 nm (ageing at 673 K for 1 and 4 hours) is characterized by storing considerable elastic energy. It is revealed that these single crystals exhibit higher cyclic stability of superelasticity and a narrower stress hysteresis compared to those in the initial state and aged at 823 K for 0.5 hour, the latter containing much larger (150–300 nm) particles.