DMA characterization of a Ni50.5at%Ti shape memory alloys

Issue title: E-MRS Fall Meeting 2005

Article type: Research Article

Authors: Besseghini, Stefano^a | Villa, Elena^{a; *} | Portman, Jenni^a

Affiliations: [a] CNR IENI Istituto per l'Energetica e le Interfasi – Consiglio Nazionale delle Ricerche Corso Promessi Sposi, 29 I-23900 Lecco, Italy

Correspondence: [*] Corresponding author: Cso Promessi Sposi, 29- Lecco, Italy. Tel.: +39 341499181; Fax: +39 341499214; E-mail: [email protected]

Abstract: It is well-known that the special properties of NiTi shape memory alloys strongly depend on their microstructure and their thermomechanical state. DSC and mechanical tests (stress-strain vs temperature) do provide extensive information on the transformation temperatures and on the pseudoelastic effect: a Dynamic Mechanical Analyzer (DMA) is further able to investigate even more transition effects, because it makes it possible to study the transition temperatures in both stressed and unstressed conditions over a wide temperature range (−150°C; 600°C). Moreover, through dynamic experiments one can to analyse the linear mechanical response and the viscoelastic properties in different ranges of strains and frequency. In this work we measure the response of NiTi in the austenitic and rhombohedral phase. We test the material both in isothermal condition over a frequency range and at a constant frequency over a temperature ramp. The NiTi samples used were Ni50.5at%Ti wires, 80 μm in diameter, thermally treated at 450°C for 1.8 Ks.

Keywords: Shape memory alloys, NiTi, DMTA, DMA

DOI: 10.3233/JAE-2006-728

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 23, no. 1-2, pp. 33-38, 2006