Effect of thermomechanical treatment on deformational behavior of ferromagnetic Fe-Ni-Co-Ti alloy under uniaxial tension

To improve the functional properties of a ferromagnetic shape memory alloy, a thermomechanical treatment that includes drawing followed by quenching and high-temperature annealing was proposed, as a result of which a nanostructured state is formed. Thermomechanical treatment (TMT) increases the alloy thermoelasticity, although it is accompanied by a large temperature hysteresis of martensitic transformation and results in a significant hardening of the matrix, which, in its turn, enlarges the effects of shape memory and superelasticity (or pseudoelasticity). It has been established that TMT of Fe-Ni-Co-Ti shape memory alloy contributes to an increase in reversible superelastic deformation up to similar to 3%. In a superelastic cycle with wide mechanical hysteresis, a large dissipation energy per loading-unloading cycle was gained, that favors the use of this alloy as a damper of mechanical oscillations.