Peculiarities of TiNi-based shape memory alloys local crystalline structure

Abstract

The extended X-ray absorption fine structure spectroscopy (EXAFS) was applied to investigate the local structure peculiarities of TiNi-based shape memory alloys Ti50Ni25Cu25 and Ti 39.2Ni24.8Cu25Hf11. The phase composition of ternary alloy was examined with the additional X-ray diffraction. Our experimental results demonstrate that the most significant changes in local crystalline structure under martensitic transformation arise in the Ni-Cu sublattice. The static disordering of the Ti coordination shell is more significant for Ni than for Cu environment. Such a conclusion is consistent with the refined values of atomic ν-shifts from the planar center of symmetry in (010) layers which are greater for Ni atoms than for Cu. © Published under licence by IOP Publishing Ltd.