Influence of pre-strain on recovery stress of annealed NiTi thin wire during isothermal holding

Yan, Xiaojun; Humbeeck, Jan Van

doi:10.1016/j.jallcom.2010.09.156

Cited by 17 publications

(7 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…But the amount of these expansions is very small because the coefficient of thermal expansion of NiTi is about 6.6 ~ 11 × 10 –6 /°C and the clamps used in this study was INVAR clamps with low coefficient of thermal expansion. The recovery stress relaxation during isothermal holding can be attributed to dislocation movement caused by the recovery stress assisted by internal stresses .…”

Section: Resultsmentioning

confidence: 99%

Temperature and Time Dependence on Recovery Stress Relaxation in Nickel Titanium Wire during Isothermal Holding at High Temperatures

Yan

Humbeeck

2013

Strain

View full text Add to dashboard Cite

In this study, the influence of kinematically constrained thermal cycling (heating, isothermal holding and cooling) on the recovery stress in annealed nickel titanium wire was investigated. A 4% pre-strained nickel titanium wire was heated to temperatures (150, 200, 250 and 300°C) much higher than the austenite finish temperature. It was observed that the maximum recovery stress obtained at different conditions decreases significantly after the first thermal cycle and reduces gradually with further increasing the number of thermal cycles. It was also seen that the recovery stress increases with time during isothermal holding at 150°C. During isothermal holding at other temperatures, the recovery stress shows an exponential decrease, and the decrease rate of the recovery stress depends on the isothermal holding temperature. The higher isothermal holding temperature is the more the recovery stress decreases. The decrease rate reduces with increasing the number of thermal cycles.

show abstract

Section: Resultsmentioning

confidence: 99%

Temperature and Time Dependence on Recovery Stress Relaxation in Nickel Titanium Wire during Isothermal Holding at High Temperatures

Yan

Humbeeck

2013

Strain

View full text Add to dashboard Cite

show abstract

“…However, in view of the transformation A→M, a further decrease of the composite curvature calculated with equation (6) occurs between M S and M F , due to the decrease of SMA elastic modulus below M S . Possible causes for this difference could be the presence of some martensite retained at the end of the heating process [66][67][68] or localization of the phase transformations in the SMA beam during training and subsequent recovery. For the 2nd actuation cycle, the agreement between the evolution of curvature and deflection with the temperature is very good (figures 12(b), (d)).…”

Section: Discussionmentioning

confidence: 99%

An experimentally-driven approach to model bending in a thermally activated SMA-based beam

Fortini

Rizzoni

Suman

et al. 2018

Smart Mater. Struct.

View full text Add to dashboard Cite

In this paper, the bending behavior of an active SMA-based beam, made up of a NiTi alloy strip externally joined to a PA66-GF30 polymeric lamina, is examined. Firstly, experimental investigations were conducted in a purpose-built test bench where a forced airflow promoted the reverse and forward phase transformations of the NiTi strip via heating and cooling ramps. The macroscopic shape changes associated with the shape memory effect deforms the structure in the cantilevered condition. The evolution of the shape memory behavior was investigated via digital image analysis, performed at both the end of heating and the end of the thermal cycle on cooling. Next, a theoretical prediction combining the classical beam model for bending with the assumption of incomplete recovery upon cooling was developed. The theoretical results indicate good agreement with experimental data showing how the proposed approach can be effectively used to predict the behavior in bending of SMA-based actuator working in controlled recovering condition.

show abstract

“…With an increase in annealing time, the phase transformation temperature of R-B19' in TiNi alloys increases, and B2-B19' phase transformation is separated from B2-R transformation [37,38]. Additionally, with an increase in annealing temperature, the recovery property of TiNi alloys decreases [39,40]. Heat treatment affects the second phase in TiNi-based alloys.…”

Section: Introductionmentioning

confidence: 99%

Effect of Annealing on the Microstructure, Texture, and Properties of Cold-Rolled Ti50Ni47Fe3 Shape Memory Alloy Sheets

Liu,

Song,

et al. 2024

Crystals

View full text Add to dashboard Cite

A systematic study was conducted on the impact of annealing treatments on the microstructure and properties of cold-rolled Ti50Ni47Fe3 alloys using optical microscopy, scanning electron microscopy, electron backscattered diffraction, and an electronic universal testing machine. It was found that, during low-temperature annealing (400 °C and 500 °C), the annealing time had no significant effect on the microstructure or properties of the Ti50Ni47Fe3 alloy. Only elongation (δ) increased with the increase in the annealing time, and the grain orientation of the Ti50Ni47Fe3 alloy was <111>//RD (rolling direction). When annealing at medium–high temperature (600 °C), as the annealing time increased, recrystallization and grain growth processes occurred, resulting in a continuous decrease in strength and an increase in δ. Meanwhile, it was found that the grain orientation of the cold-rolled Ti50Ni47Fe3 alloy changed from <111>//RD during the recovery and recrystallization processes to <101>//RD after the grain growth process. The orientation distribution function cross-section φ2 = 45° results indicate that the texture was mainly distributed along the γ orientation line (φ1 = 0~90°, Φ = 54.7°, φ2 = 45°). When annealed at 400 °C and 500 °C, the texture of the Ti50Ni47Fe3 alloys was (111)[uvw]. When the annealing treatment was 600 °C for 120 min, a (110)[uvw] texture occurred. Additionally, ductile fracture occurred in all specimens, and the crack origin was located on one side of the fracture surface, with obvious “Y”-shaped propagation. This article studied annealing treatments of cold-rolled Ti50Ni47Fe3 alloys, providing corresponding theoretical guidance for subsequent production applications.

show abstract

Influence of pre-strain on recovery stress of annealed NiTi thin wire during isothermal holding

Cited by 17 publications

References 25 publications

Temperature and Time Dependence on Recovery Stress Relaxation in Nickel Titanium Wire during Isothermal Holding at High Temperatures

Temperature and Time Dependence on Recovery Stress Relaxation in Nickel Titanium Wire during Isothermal Holding at High Temperatures

An experimentally-driven approach to model bending in a thermally activated SMA-based beam

Effect of Annealing on the Microstructure, Texture, and Properties of Cold-Rolled Ti50Ni47Fe3 Shape Memory Alloy Sheets

Contact Info

Product

Resources

About