M. I. Petrzhik, J. S. Zhukova, S. D. Prokoshkin, Moscow Institute of Steel and Alloys, Moscow, Russia
Products of martensitic transformation in quenched Ti-(Ta,Nb) alloys have been studied by determination of elastic E and G moduli, thermal analysis, mechanical tests and nano-indentation. The results were analyzed taking into account XRD data on phase composition and degree of distortion R=√3a/b of orthorhombic alfa’’-martensite (Cmcm space group) according to Yu.A. Bagariatskii’s diagram. It was found that realization of Shape Memory and Superelasticity (up to 2.5% returnable deformation) was possible at alloys having extremely low Young’s modulus (about 60 GPa) and the largest rhombic distortion (about R=1.16) of unit cell. Also it was noted high thermal stability of the martensitic structure against thermal cycling. Some possible medical applications of Shape Memory and Superelasticity effects at the alloys contained Ti, Ta, and Nb metals, which are known to be friendly to human body, are discussed.
