Orientation dependence of functional properties of alloys with shape memory effect and superelasticity

As applied to alloys with shape memory effects (SME) and superelasticity (SE), the results of an X-ray study of the orientational dependence of their functional properties are presented, which are associated with martensitic transformations (MTs) underlying the above effects. The observed orientational effects are conditioned by the inhomogeneity of the substructure state of grains with different orientations in polycrystalline materials and the anisotropy of the influence of the given loads on the alloy crystal lattice. It was shown that the detection of the inhomogeneous flow of MPs in grains of studied samples proves to be possible only due to of the selectivity of X-ray diffraction. In particular, it was found the following facts: (1) The width of the reverse MT interval in a rolled and quenched Ti-Ni alloy varies more than by 40 K; (2) foils from the Fe-28% Ni-5Mo% alloy, stretched along and across the rolling direction, differ in temperatures of the reverse MT beginning by 200 K; (3) the 100% SME was observed in single crystals from a Ti – Ni alloy with stable orientations by a given deformation of $\sim$ 15%; (4) the SME in foils from the Fe-28Ni-5Mo alloy, stretched in different directions to the defining deformation $\delta \approx 6$ %, differ by an order of value. It has been established that in superelastic Ti-Nb-based alloys, which have a two-component rolling texture, like all metallic materials with a bcc lattice, the martensitic transformation $\beta \leftrightarrow \alpha''$ under compression is localized in less fragmented grains with the rolling plane $\{001\}$, while in grains with the rolling plane $\{111\}$ it is almost absent.