Phase transformations and fatigue of NiTi

0485660 - FZÚ 2018 RIV FR eng C - Conference Paper (international conference)
Alarcon, E. - Heller, Luděk - Chirani, S.A. - Šittner, Petr - Saint-Sulpice, L. - Calloch, S.
Phase transformations and fatigue of NiTi.
ESOMAT 2015 - 10th European Symposium on Martensitic Transformations. P.A. de Courtabœuf: E D P Sciences, 2015 - (Schryvers, N.; Van Humbeeck, J.), s. 1-6, č. článku 03011. MATEC Web of Conferences, 33. ISBN 978-2-7598-1925-6. ISSN 2261-236X.
[European Symposium on Martensitic Transformations /10./. Antwerp (BE), 14.09.2015-18.09.2015]
R&D Projects: GA ČR GA14-15264S; GA ČR GAP107/12/0800
Institutional support: RVO:68378271
Keywords : shape memory alloys * nitinol * martensitic transformation * fatigue
OECD category: Audio engineering, reliability analysis

Tensile fatigue of superelastic medical graded NiTi wires was analysed in stress control regime with special attention paid to the deformation/transformation processes involved. Concave shaped samples were machined from NiTi wires allowing us to confine deformation processes into the centre of the sample. The localization of phase transformations within the centre was confirmed using in-situ infrared imaging. Characteristic stress-displacement responses for amplitudes inducing either R-phase only or both R-phase and martensite were identified for these samples. A limited number of pull-pull fatigue tests in force-control regime were performed. The obtained S-N curve and associated stress-displacement responses allowed for identification of three fatigue regimes differing in the fatigue life-time by orders of magnitude. Particularly, fatigue life-time deteriorating effect of R-phase transformation was identified.

Permanent Link: http://hdl.handle.net/11104/0280629