Influence of the Post-Deformation Annealing Heat Treatment on the Low-Cycle Fatigue of NiTi Shape Memory Alloys

Shape memory alloys (SMAs) are unique materials capable of undergoing a thermo-mechanically induced, reversible, crystallographic phase transformation. As SMAs are utilized across a variety of applications, it is necessary to understand the internal changes that occur throughout the lifetime of SMA components. One of the key limitations to the lifetime of a SMA component is the response of SMAs to fatigue. SMAs are subject to two kinds of fatigue, namely structural fatigue due to cyclic mechanical loading which is similar to high cycle fatigue, and functional fatigue due to cyclic phase transformation which typical is limited to the low cycle fatigue regime. In cases where functional fatigue is due to thermally induced phase transformation in contrast to being mechanically induced, this form of fatigue can be further defined as actuation fatigue. Utilizing X-ray computed microtomography, it is shown that during actuation fatigue, internal damage such as cracks or voids, evolves in a non-linear manner. A function is generated to capture this non-linear internal damage evolution and introduced into a SMA constitutive model. Finally, it is shown how the modified SMA constitutive model responds and the ability of the model to predict actuation fatigue lifetime is demonstrated.

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Precipitates Formation in Ti-Ni Equiatomic Alloys due to Annealing Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.643.49 ◽

2010 ◽

Vol 643 ◽

pp. 49-54 ◽

Cited By ~ 1

Author(s):

Carlos Augusto Nascimento Oliveira ◽

Euclides Apolinário Cabral De Pina ◽

Cezar Henrique Gonzalez ◽

Carlos José de Araújo ◽

U.S.L. Filho ◽

...

Keyword(s):

Heat Treatment ◽

Martensitic Transformation ◽

Shape Memory ◽

Martensitic Transformations ◽

Smart Material ◽

X Ray Diffraction ◽

X Ray ◽

Metallurgical Investigation ◽

Annealing Heat Treatment ◽

Annealing Heat

The use of smart material such as Ti-Ni in actuators application requires an intense mechanical and metallurgical investigation to understand its behavior. This paper studies martensitic transformation using DSC and X-ray diffraction techniques to compare shape memory parameters in Ti-50.2%Ni (A1) and equiatomic Ti-50.0%Ni (A2) Alloys. The as as-received samples were submitted to annealing at 400°C and 500°C for 24 hours then quenched in at 25°C. The influence of heat treatment on martensitic transformations temperatures and the appearance of R-phase were analyzed using DSC and X-ray diffraction.

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Phase transformation volume amplitude as a low-cycle fatigue indicator in nickel–titanium shape memory alloys

Scripta Materialia ◽

10.1016/j.scriptamat.2019.12.014 ◽

2020 ◽

Vol 178 ◽

pp. 442-446 ◽

Cited By ~ 3

Author(s):

Harshad M. Paranjape ◽

Bill Ng ◽

Ich Ong ◽

Lot Vien ◽

Christopher Huntley

Keyword(s):

Phase Transformation ◽

Shape Memory Alloys ◽

Shape Memory ◽

Low Cycle Fatigue ◽

Nickel Titanium ◽

Cycle Fatigue

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Vacuum brazing and heat treatment of NiTi shape memory alloys

IOP Conference Series Materials Science and Engineering ◽

10.1088/1757-899x/1147/1/012025 ◽

2021 ◽

Vol 1147 (1) ◽

pp. 012025

Author(s):

W Tillmann ◽

A Eilers ◽

T Henning

Keyword(s):

Heat Treatment ◽

Shape Memory Alloys ◽

Shape Memory ◽

Vacuum Brazing ◽

Niti Shape Memory Alloys

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Constitutive Modeling of Near-Equiatomic NiTi Shape Memory Alloys Considering Composition and Heat Treatment

Materials Science Forum ◽

10.4028/www.scientific.net/msf.856.78 ◽

2016 ◽

Vol 856 ◽

pp. 78-84

Author(s):

Austin Cox ◽

Theocharis Baxevanis ◽

Dimitris C. Lagoudas

Keyword(s):

Heat Treatment ◽

Shape Memory Alloys ◽

Shape Memory ◽

Volume Fraction ◽

Lattice Mismatch ◽

Memory Performance ◽

Matrix Material ◽

Precipitate Growth ◽

The Matrix ◽

Niti Shape Memory Alloys

A predictive microscale-informed model that takes into account the precipitate–shape memory performance relations and allows for the evaluation of the effective thermomechanical response of precipitated Ni-rich NiTi shape memory alloys on the basis of composition and heat treatment is presented. The model considers the structural effect of the precipitates (coherency stresses due to the lattice mismatch between the precipitates and the matrix material and precipitate volume fraction), as well as the effect of the Ni-concentration gradient in the matrix, resulting from Ni-depletion during precipitate growth. The predictive capability of the model is tested against experimental data obtained fromNi50.7Ti (at. %) that has been heat treated under different conditions and good agreement is shown.

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Experimental and theoretical investigation of the frequency effect on low cycle fatigue of shape memory alloys

International Journal of Plasticity ◽

10.1016/j.ijplas.2016.11.012 ◽

2017 ◽

Vol 90 ◽

pp. 1-30 ◽

Cited By ~ 42

Author(s):

Yahui Zhang ◽

Yajun You ◽

Ziad Moumni ◽

Gunay Anlas ◽

Jihong Zhu ◽

...

Keyword(s):

Shape Memory Alloys ◽

Shape Memory ◽

Theoretical Investigation ◽

Low Cycle Fatigue ◽

Frequency Effect ◽

Cycle Fatigue

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Effect of heat treatment on the two-way recovery stress of tube-shaped NiTi

Journal of Intelligent Material Systems and Structures ◽

10.1177/1045389x12444489 ◽

2012 ◽

Vol 23 (10) ◽

pp. 1161-1168 ◽

Cited By ~ 4

Author(s):

Young Ik Yoo ◽

Ju Won Jeong ◽

Jung Ju Lee ◽

Chang Ho Lee

Keyword(s):

Heat Treatment ◽

Shape Memory ◽

Annealing Temperature ◽

Recovery Stress ◽

Treatment Conditions ◽

Heat Treated ◽

Annealing Heat Treatment ◽

Optimum Annealing Temperature ◽

Tubular Specimens ◽

Annealing Heat

The effect of annealing temperatures on the thermomechanical behavior of NiTi in terms of transformation temperatures, mechanical properties, two-way shape memory strain, and two-way recovery stress was investigated experimentally to develop a NiTi tubular actuator with high two-way recovery force. Five tubular specimens were used to obtain the two-way shape memory strain and two-way recovery stress by varying heat treatment conditions. Annealing heat-treated temperatures were 400°C, 500°C, 600°C, 700°C, and 800°C. A two-way shape memory effect was introduced in the shape memory alloy tube by thermomechanical treatment after annealing heat treatment. According to the results, the two-way strain induced by shape memory cycling was independent of the annealing temperature. However, the two-way recovery stress generated by the two-way strain depended on the annealing temperature, even though the values of the two-way strain were similar in all specimens. Considering all heat treatment results, we concluded that the optimum annealing temperature to acquire two-way recovery stress and two-way strain for an actuator is 600°C.

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