Isothermal B2→B19′ martensitic transformation in Ti40.7Hf9.5Ni44.8Cu5 shape memory alloy

Resnina, Natalia; Belyaev, Sergey; Shelyakov, A. V.

doi:10.1016/j.scriptamat.2015.09.024

Cited by 20 publications

(7 citation statements)

References 24 publications

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“…In fact, there exist different factors that may contribute to the observed time-dependence of a particular transformation. Most of them include relaxation processes that occur during dwelling due to the interaction between the crystal lattice defects and moving phase interfaces [8,9,33] and the development of strain nanodomains [34]. In fact, isothermal MT was observed in non-stoichiometric Ti-Ni alloys but not found in the equiatomic TiNi alloy [34].…”

Section: Resultsmentioning

confidence: 99%

“…Most of them include relaxation processes that occur during dwelling due to the interaction between the crystal lattice defects and moving phase interfaces [8,9,33] and the development of strain nanodomains [34]. In fact, isothermal MT was observed in non-stoichiometric Ti-Ni alloys but not found in the equiatomic TiNi alloy [34]. This phenomenon was associated to the formation of strain nanodomains and the existence of substitutional atoms.…”

Section: Resultsmentioning

confidence: 99%

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Thermal arrest analysis of the reverse martensitic transformation in a Ni55Fe19Ga26 Heusler alloy obtained by melt-spinning

Vidal-Crespo

Manchón-Gordón

Blázquez

et al. 2022

J Therm Anal Calorim

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Ni55Fe19Ga26 ribbons obtained by melt-spinning technique exhibit a martensitic transformation from L21 cubic austenite phase to 14 M martensite phase above room temperature. We have taken advantage of the existence of thermal hysteresis of the martensitic phase transition (~ 11 K) to analyze the effect of isothermal treatments on the reverse martensitic transformation, which has been analyzed by means of interrupted heating using differential scanning calorimetry. The experimental findings clearly indicate a time-depending effect in the martensitic transformation at temperatures between the austenite start and finish temperatures. Moreover, it has been observed that two successive martensitic transformations take place after the isothermal arrest was performed.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Thermal arrest analysis of the reverse martensitic transformation in a Ni55Fe19Ga26 Heusler alloy obtained by melt-spinning

Vidal-Crespo

Manchón-Gordón

Blázquez

et al. 2022

J Therm Anal Calorim

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“…Recently, it has been shown that some NiTi-based shape memory alloys undergo the forward martensitic transformation during holding at a constant temperature close to M s (start temperature of the forward martensitic transition) [1][2][3][4][5][6][7]. The kinetics of this process is well studied experimentally, and it is established that the martensite volume fraction increases with time up to a saturation value, which depends on the holding temperature in a nonmonotonic way [5 -7].…”

Section: Introductionmentioning

confidence: 99%

Simulation of isothermal reversible strain in the Ti40.7Hf9.5Ni44.8Cu5 alloy using a microstructural model

Demidova

Belyaev

et al. 2021

Lett. Mater.

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Recently it has been found that some NiTi-based alloys may undergo the forward martensite transition on isothermal holding. Moreover, such isothermal transformation under stress is accompanied by variation in reversible strain. At the same time, theoretical models do not allow describing the recoverable strain variation during holding. The aim of the present study was to adjust the microstructural model earlier developed by V. Likhachev and A. Volkov for describing strain variation due to the formation of the martensite phase on holding of NiTi-based alloys under a constant stress at temperatures within the temperature range of the forward martensite transformation. To take into account the possibility for isothermal martensite formation, a new suggestion was made, according to which the isothermal kinetics might be controlled by some relaxation process, which could change the local density of point defects and led to the fulfillment of thermodynamics condition for transformation. To include this assumption into the model some modifications have been added to constitutive equations. The modified microstructural model was used to simulate the strain variation, caused by isothermal martensite formation under various stresses. The influence of holding parameters (temperature and stress) on the maximum isothermal strain was found, and a good agreement between the simulated and experimental results was obtained. It was shown that the modified microstructural model allowed predicting the holding temperature and the stress at which the maximum isothermal strain can be found.

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“…In recent years, it has been found that in some NiTi-based alloys, the thermoelastic martensitic transformation can occur during holding at a constant temperature that is higher than the starting temperature of the forward transition M s [1][2][3][4][5][6][7] or within the temperature range of the forward transformation [1, 5 -10]. This phenomenon has been well studied experimentally and the kinetics of this process is described in [4 -6].…”

mentioning

confidence: 99%

“…Thus, the aim of the present study is to adapt and use the JMAK theory for estimation of Φ M variation with time during holding of Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 alloy at different temperatures. Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 alloy was chosen due to it underwent the martensitic transformation during isothermal holding and a large amount of experimental data was available on the isothermal kinetics of thermoelastic martensitic transformations for this alloy [4,5]. In [4] it is shown that the fully crystalline Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 alloy with the grain size of 700 nm (details of crystallization are described in [4]) undergoes B2← →B19ʹ martensitic transformations at temperatures: M s = 266 K, M f = 260 K, A s = 302 K and A f = 325 K [4].…”

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confidence: 99%

Simulation of isothermal kinetics of martensitic transformation in the Ti40.7Hf9.5Ni44.8Cu5 alloy

2020

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The realization of forward martensitic transformation under isothermal conditions in NiTi-based alloys has been well studied experimentally, along with the kinetics of this process. However, existing models do not allow the isothermal martensite volume fraction Φ M to be estimated, hence the influence of holding temperature or time on the Φ M value could not be calculated. The Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory is normally used to describe isothermal kinetics, but it has not been applied for martensite transformation, which occurs in shape-memory alloys during holding at a constant temperature. Thus, the aim of the present study is to adapt the JMAK theory and use to estimate Φ M variation with time during holding of Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 alloy at different temperatures. The JMAK equation allows the variation of the isothermal martensite volume fraction with time during holding at constant temperatures to be approximated. It was applied to estimate experimental Φ M (t) curves in Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 alloy and a good approximation was established. The dependencies of JMAK-like equation parameters on the holding temperature were also found and approximated. Thus, the expression for the dependence of the isothermal martensite volume fraction on holding temperature and time was found and calculation of the Φ M (t) curves was carried out. The simulated and experimental data for the Ti 40.7 Hf 9.5 Ni 44.8 Cu 5 shape memory alloy were shown to be in good agreement.

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Isothermal B2→B19′ martensitic transformation in Ti40.7Hf9.5Ni44.8Cu5 shape memory alloy

Cited by 20 publications

References 24 publications

Thermal arrest analysis of the reverse martensitic transformation in a Ni55Fe19Ga26 Heusler alloy obtained by melt-spinning

Thermal arrest analysis of the reverse martensitic transformation in a Ni55Fe19Ga26 Heusler alloy obtained by melt-spinning

Simulation of isothermal reversible strain in the Ti40.7Hf9.5Ni44.8Cu5 alloy using a microstructural model

Simulation of isothermal kinetics of martensitic transformation in the Ti40.7Hf9.5Ni44.8Cu5 alloy

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