Open Access
Article Number 05015
Number of page(s) 7
Section Applied Research and Applications: Engineering Materials with MT
Published online 01 September 2009
ESOMAT 2009, 05015 (2009)
DOI: 10.1051/esomat/200905015

Structure and shape recovery characteristics of Ti-50.0%Ni thermomechanically treated industrial wire

I.Yu. Khmelevskaya1, S.D. Prokoshkin1, S.Yu. Makushev2, A.B. Bondarev3 and V.A. Andreev3

1  Moscow Institute of Steel and Alloys, Russia
2  Kurdymov Institute of Metal Physics, Moscow, Russia
3  Industrial Center MATEKS, Moscow, Russia

Published online: 1 September 2009

The effect of post-deformation annealing (PDA) temperature in a range 300 to 700°C and induced stain (3 to 24%) on shape recovery temperature range (SRTR) was studied for an industrial Ti-Ni wire. To determine the characteristic temperatures of martensitic transformations, a differential scanning calorimetry was used. SRTR was determined by the method of bending deformation followed by heating for shape recovery. The wire structure was studied by X-ray diffraction and TEM methods. The original structure of wire is a B19'- martensite or a mixture of B19', R -phase and B2- austenite containing a well-developed dislocation substructure. To obtain structure uniformity along the wire length, the PDA temperatures of 500-600°C are recommended. The SRTR at the wire of near-equiatomic Ti-Ni alloys produced by warm drawing can be controlled using PDA in the temperature range 400 to 700°C. SRTR in the 70-100°C range is achieved by means of PDA at 400 to 650°C (SRTR increases in this PDA range). With the increasing of induced strain from 5 to 24%, the high-temperature shape memory effect is appears and grows: a non-monotonic AF growth from 90 to 150°C and SRTR broadening are observed. Shape recovery parameters of studied wire are high: the maximum completely recoverable strain of 4 - 5%, the maximum recoverable strain of 7 - 13%, and they can be controlled using PDA.

© Owned by the authors, published by EDP Sciences 2009