Stress-indused martensitic transformation in [110]-oriented Ni51Fe18Ga27Co4 single crystals

In the present study, we investigated the stress-indused termoelastic martensitic transformations in Ni^iFeif}a27Co4 single crystals oriented along the [110]-direction. It was shown that high-temperature annealing at a temperature higher than the order-disorder transition temperature affects of the stress-indused termoelastic martensitic transformations due to a change in the structure of the high-temperature phase of L2j by B2, the dissolution of the /-phase. The isobaric experiments (shape memory effect) under external applied stress (T = 100 МПа have shown that for (L21 + yf crystals of the reversible deformation is Ssme = 2,1 % with insignificant irreversibility and thermal hysteresis AT = (29 ± 2) K. For B2-crystals the reversible deformation Ssme = 4,5%, accompanied by the presence of an irreversible deformation to ~ 1,6% and the thermal hysteresis value AT = (61 ± 2) K. The isothermal experiments (superelasticity) shown the energy dissipation at T = 323 К is A(T = (89 ± 2) MPa and decreases with increasing test temperature in the B2-crystals