Influence of Deformation during Warm Rolling on Martensitic Transformation Temperatures and the Value of Superelasticity and Shape Memory Effects in Ti_(49.2)Ni_(50.8) (at %) Alloy

摘要

The influence of the warm isothermal (723 K) rolling in grooved rolls on the grain structure, martensitic transformation temperatures, and inelastic properties of Ti_(49.2)Ni_(50.8) (at %) alloy is investigated. It is shown that transition from initial coarse-grained structure to micro- and submicrocrystalline structures of samples occurs as a result of rolling with the intense deformation to 1.8. The inelastic properties (superelasticity and shape memory effects) are studied under torsion deformation. The value of the superelasticity effect (including the elastic deformation) was determined in isothermal (295 K) "loading-unloading" cycles. The value of the shape memory effect is equal to the recovery of inelastic deformation under heating of unloaded samples. The accumulated plastic deformation corresponds to the residual deformation after the completion of shape recovery under heating. The total inelastic deformation under torsions of rolled sample reaches 8.5-9.5% (99% of the degree of shape recovery), the shape memory effect is 5-6%, and the superelasticity effect is 3-4%.