Shape Memory Effect and Superelasticity of Ni-Free Ti-Nb-based Alloys
ZHOU Zheng-cun
GUO De-wen
DU Jie
ZHANG Yi-ping
GU Su-yi
YAN Yong-jian
Abstract：Ni-Free Ti-Nb-based alloys have potential application as superelastic alloys with non-toxic shape memory. The shape memory behavior and superelasticity of free-Ni Ti-Nb-based alloys are described and discussed in this paper. It is shown that the excellent shape memory behavior and superelasticity can be obtained by a suitable chemical composition and heat treatments.β-Ti-Nb alloys undergo a martensitic transformation when thay are rapidly cooled from theβphase region at high temperatures. This transformation producesα’orα”martensite. The transformation from β phase to α”martensite is a thermoelastic one and thereby produces shape memory effect and superelasticity. The start temperature of martensitic transformation (Ms) decreases with increasing Nb contents. Nb contents are located between 22-26at.% among the reported Ti-Nb alloys since the superelasticity at room temperature exists when the Ti-Nb alloys have the compositions of 22-26at.%Nb. The addition of the elements such as Zr,Sn,O and Al have influences on the shape memory effect and superelasticity of Ti-Nb alloys,which decreases Ms and increases superelasticity. Ti-22Nb-4Zr (at.%) and Ti-24Nb-3Al (at.%) possess large recovery strain. The maximum recovery strain is 4.3%for the former and 4.7%for the latter,respectively.
Keywords：Ni-Free Ti-Nb-based alloysshape memory behaviorsuperelasticity
Publication Date：2015-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 1-6 )