Constrained recovery properties of NiTi shape memory alloy wire during thermal cycling

Li, Y.F.; Mi, Xujun; Yin, Xiang; Xie, Haofeng

doi:10.1016/j.jallcom.2013.11.074

Cited by 10 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Upon heating, NiTi undergoes a reversible phase transformation to an austenite structure and tries to resume its parent geometry. If the NiTi is prevented from returning to its parent geometry, known as constrained recovery, it can produce stresses on the order of several hundred MPa [9,10]. Combined, the ability to actuate over large strains and produce large stresses mean that NiTi SMAs have a very high specific energy density, making them useful as actuators [11].…”

Section: Motivationmentioning

confidence: 99%

Investigation into post constrained recovery properties of nickel titanium shape memory alloys

Haider

Rezaee

Yazdi

et al. 2019

Smart Mater. Struct.

View full text Add to dashboard Cite

Experimental investigations have found that nickel titanium (NiTi) shape memory alloys (SMAs) exhibit a phenomenon wherein the material can be recoverably deformed in its low temperature martensitic state, thermally actuated to its austenite state while constrained from returning to its parent geometry, and upon ceasing actuation and return to the low temperature martensite state it will continue to generate post constrained recovery residual stresses (PCRRS). The ability to generate a PCRRS creates a new way for SMAs to be used but the stability of the PCRRS, response to subsequent loading, and underlying microstructural mechanisms that generate the PCRRS are poorly understood. This paper presents an experimental investigation into the thermomechanical response of NiTi beginning from a PCRRS state. Multiple formulations of NiTi were exposed to training and sequences of cyclic deformation and thermal actuation in this study. It was found that repeated application of 0.5% strain reduced the residual stress with each application and thermal actuation would restore the original PCRRS. Training and mechanically working the material stabilized the thermomechanical response and did not significantly degrade the magnitude of the PCRRS. Understanding of PCRRS supports a new way for materials to be used as actuators, storing potential energy in material structures that may be beneficial to self-healing material, fatigue crack prevention and other applications.

show abstract

Section: Motivationmentioning

confidence: 99%

Investigation into post constrained recovery properties of nickel titanium shape memory alloys

Haider

Rezaee

Yazdi

et al. 2019

Smart Mater. Struct.

View full text Add to dashboard Cite

show abstract

“…However, it is worth noting that this kind of constraint recovery (introducing reset layer to provide mechanical TWSME) could significantly affect the recovery properties (i.e., transition temperature and maximum stress) in contrast with the free recovery (without reset layer) [95,96]. Beside a cantilever type, a novel and unique SMA spiral-coil out-of-plane actuator is reported by Ali et al [97].…”

Section: W E E T T T T T R W E T W E T W W E E T T T T T Tmentioning

confidence: 99%

Micromachined Shape-Memory-Alloy Microactuators and Their Application in Biomedical Devices

2015

View full text Add to dashboard Cite

Shape memory alloys (SMAs) are a class of smart materials characterized by shape memory effect and pseudo-elastic behavior. They have the capability to retain their original form when subjected to certain stimuli, such as heat or a magnetic field. These unique properties have attracted many researchers to seek their application in various fields including transportation, aerospace, and biomedical. The ease process adaption from semiconductor manufacturing technology provides many opportunities for designing micro-scale devices using this material. This paper gives an overview of the fabrication and manufacturing technique of thin-film and bulk micromachined SMAs. Key features such as material properties, transformation temperature, material composition, and actuation method are also presented. The application and micromechanism for both thin-film and bulk SMA are described. Finally, the microactuator devices emphasized for biomedical applications such as microgrippers and micropumps are highlighted. The presented review will provide information for researchers who are actively working on the development of SMA-based microscale biomedical devices.

show abstract

“…structures in the field of elastocaloric cooling was introduced by Kordizadeh et al [19] It was demonstrated that phase transformation did not occur in some portions of the materials due to the nonuniform strain/stress distribution in porous structures, resulting in a lower elastocaloric effect. [19] At present, a large number of experiments have been carried out on the effects of thermal cycle and porosity on the phase transformation and mechanical properties of NiTi SMA materials, [7,[9][10][11][12][13][14][15][16][17][18][19] but the microstructure changes in the process of martensitic transformation, especially the micromechanisms of martensitic transformation at atomic scale under thermal cycling conditions are not clear.…”

Section: Introductionmentioning

confidence: 99%

“…[12] The effects of prestrain and thermal cycling on the recovery stress and phase transformation temperature of Ni 50.2 Ti 49.8 (at%) SMA wires were experimentally investigated. [13] The results revealed that detwinned martensite contributed to the inverse phase transformation process, causing austenitic start temperature to fall but stabilize after the second thermal cycle. The entangled dislocations generated by thermal cycling made twin boundary motion difficult, [14] and pure dislocations and vacancies on dislocations were found during cycling, [15] both concentrated near the R phase.…”

mentioning

confidence: 96%

Effects of Thermal Cycling and Porosity on Phase Transformation of Porous Nanocrystalline NiTi Shape Memory Alloy: An Atomistic Simulation

Liu,

Wang,

2023

Adv Eng Mater

View full text Add to dashboard Cite

In this paper, the effects of thermal cycling and porosity on the martensitic phase transformation behavior of porous nanocrystalline (NC) NiTi shape memory alloys (SMAs) at the atomic scale are investigated by molecular dynamics (MD) simulation. The simulation results show that thermal cycling causes the NC NiTi SMAs to repeatedly undergo martensitic phase transformation and inverse phase transformation processes. The martensitic phase transformation capability is suppressed with increasing porosity and number of cycles, but the suppression effect of thermal cycling is weakened with increasing porosity. Moreover, the start temperature of martensitic transformation, residual martensitic phase, and the fraction of interstitial atoms increase with increasing porosity. Thermal cycling causes the disordered structures and shear plastic deformation to accumulate as cycling increases. Recoverable shear deformation is generated within the grain, but shear plastic deformation is mainly concentrated at both grain boundaries and pore surfaces. Residual martensitic phase increases after thermal cycling These results provide important explanations and references for a deeper understanding of phase transformation behavior and pore effects caused by thermal cycling.This article is protected by copyright. All rights reserved.

show abstract

Constrained recovery properties of NiTi shape memory alloy wire during thermal cycling

Cited by 10 publications

References 19 publications

Investigation into post constrained recovery properties of nickel titanium shape memory alloys

Investigation into post constrained recovery properties of nickel titanium shape memory alloys

Micromachined Shape-Memory-Alloy Microactuators and Their Application in Biomedical Devices

Effects of Thermal Cycling and Porosity on Phase Transformation of Porous Nanocrystalline NiTi Shape Memory Alloy: An Atomistic Simulation

Contact Info

Product

Resources

About