The High Performance Shape Memory Effect (HP-SME) in Ni Rich NiTi Wires: In Situ X-Ray Diffraction on Thermal Cycling

Ti–18Zr–xNb–2Sn (x = 10, 11, 11.5, 12, 12.5) (at.%) shape memory alloys were fabricated by arc melting then phase constitutions and superelastic properties were investigated by X-ray diffraction (XRD) and tensile test at various temperatures between 178 K and 413 K. Excellent superelasticity was observed in 12.5Nb alloy at temperatures between 258 K and 298 K. Both superelasticity and shape memory effect were observed in 12Nb alloy at temperatures between 233 K and 383 K. Only shape memory effect was observed in 11Nb and 11.5Nb alloys at temperatures between 298 K and 383 K. 12.5Nb and 12Nb alloys consisted of the main β phase and athermal ω. The amount of β phase decreased with increasing Nb content. 10Nb alloy consisted of main α″ martensite and a small amount of β phase. The Ms temperature measured from the Clausius–Clapeyron relationship decreased greatly with increasing Nb content (100 K/at.% Nb) in these Ti–Zr–Nb–Sn alloys.

Download Full-text

A new type of intrinsic two-way shape-memory effect in hooks of NiTi-wires

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:20031092 ◽

2003 ◽

Vol 112 ◽

pp. 1177-1180 ◽

Cited By ~ 1

Author(s):

A. Schuster ◽

H. F. Voggenreiter ◽

D. C. Dunand ◽

G. Eggeler

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

New Type ◽

Niti Wires

Download Full-text

High performance shape memory effect in nitinol wire for actuators with increased operating temperature range

Functional Materials Letters ◽

10.1142/s1793604714500635 ◽

2014 ◽

Vol 07 (05) ◽

pp. 1450063 ◽

Cited By ~ 10

Author(s):

Riccardo Casati ◽

Carlo Alberto Biffi ◽

Maurizio Vedani ◽

Ausonio Tuissi

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

High Performance ◽

Room Temperature ◽

Operating Temperature ◽

Niti Wire ◽

Shape Memory Actuators ◽

Nitinol Wire ◽

Operating Temperature Range

In this research, the high performance shape memory effect (HP-SME) is experimented on a shape memory NiTi wire, with austenite finish temperature higher than room temperature. The HP-SME consists in the thermal cycling of stress induced martensite and it allows achieving mechanical work higher than that produced by conventional shape memory actuators based on the heating/cooling of detwinned martensite. The Nitinol wire was able to recover about 5.5% of deformation under a stress of 600 MPa and to withstand about 5000 cycles before failure. HP-SME path increased the operating temperature of the shape memory actuator wire. Functioning temperatures higher than 100°C was reached.

Download Full-text

Corrigendum to “Effect of thermal cycling on the shape memory transformation behavior of NiTi alloy: Powder X-ray diffraction study” [Mater. Sci. Eng. A. 448 (2007) 33–38]

Materials Science and Engineering A ◽

10.1016/j.msea.2009.01.001 ◽

2009 ◽

Vol 505 (1-2) ◽

pp. 191 ◽

Cited By ~ 2

Author(s):

Manjunatha Pattabi ◽

K. Ramakrishna ◽

K.K. Mahesh

Keyword(s):

Thermal Cycling ◽

Shape Memory ◽

Diffraction Study ◽

Alloy Powder ◽

Niti Alloy ◽

X Ray Diffraction ◽

Transformation Behavior ◽

X Ray

Download Full-text

Phase Constitution, Mechanical Property and Corrosion Resistance of the Ti-Nb Alloys

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.324-325.655 ◽

2006 ◽

Vol 324-325 ◽

pp. 655-658 ◽

Cited By ~ 5

Author(s):

Bao Lai Wang ◽

Yan Bo Wang ◽

Yu Feng Zheng

Keyword(s):

Corrosion Resistance ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Artificial Saliva ◽

X Ray Diffraction ◽

Phase Constitution ◽

Β Phase ◽

Bending Strain ◽

35Nb Alloy

Recently, people devote to the development of Ni-free shape memory alloys in order to avoid the Ni-hypersensitivity and toxicity and pursue absolute safety. The shape memory effect and superelasticity have been reported in the biomedical Ti-Nb based alloys. The purpose of this paper is to report the phase constitution, tensile property, shape memory effect and corrosion resistance of the Ti-Nb alloys. The phase constitutions of the Ti-Nb alloys are investigated by means of X-ray diffraction (XRD). The results reveal that β+α′′ phases are presented in the Ti-35Nb alloy and only β phase in the Ti-52Nb alloy at room temperature. The tensile test and bending tests indicate that the Ti-35Nb alloy exhibits shape memory effect. The shape recovery ratio is near to 80% when the bending strain is 4.4% and decreases with the increase of the total bending strain. The corrosion resistance of the Ti-Nb alloys in the Hank's solution and artificial saliva (pH=7.4) at 37 are investigated by OCP, Tafel and anodic polarization methods. The results indicate that the Ti-35Nb alloy has a better corrosion resistance in the artificial saliva and can replace the Ti-Ni alloy in the dental application. In the non-oral condition, the Ti-52Nb alloy may be preferable.

Download Full-text