Thermoelastic martensitic transformation in single crystals of FeNiCoAlTiNb alloy

The temperature dependence of the critical stresses and transformation strain upon cooling/heating under a constant tensile stress in the temperature range T = 77–573 K are studied on single crystals of Fe–28% Ni–17% Co–11.5% Al–2.5% (Ti+Nb) (at %) alloy oriented along the [001]-direction under tensile deformation. It is shown that at the start martensitic transformation temperature Ms the critical stress for the development of stress-induced γ–α′-martensitic transformations under isobaric and isothermal conditions differs by 7 times. The critical stress for the development of stress-induced γ–α′-martensitic transformations under isobaric and isothermal conditions become equal to each other at the external stress σext above 400 MPa. The maximum reversible strain was 4.5% at a given value of the transformation strain 9.8%.