Influences of aging and thermomechanical treatments on the martensitic transformation and superelasticity of highly Ni-rich Ti-51.5at.% Ni shape memory alloy

Aboutalebi, M.R.; Karimzadeh, M.; Salehi, Mohammad Taghi; Abbasi, S.M.; Morakabati, M.

doi:10.1016/j.tca.2015.08.004

Cited by 18 publications

(7 citation statements)

References 31 publications

(43 reference statements)

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“…During the aging, internal stresses occurred on the precipitation dispersion, and that causes volume friction between the precipitates. Therefore, Ti content increases in the matrix, and that causes the increasing of the transformation temperatures [19]. That stress effects can also be seen easily in the enthalpy graph in Figure 5.…”

Section: Resultsmentioning

confidence: 78%

Investigation of Thermomechanical Behaviors of Aged Ti55.68Ni44.32 Alloys

Özkul¹,

Canbay²

2018

Anadolu University Journal of Science and Technology-a Applied Sciences and Engineering

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TiNi alloys are used in places requiring precision jobs for the last few decades. Thermally induced shape memory alloys such as TiNi are exposed to temperature cycle during the implementation, and the temperature causes an artificial aging effect on the alloy. In this study, we aimed at investigating whether the aging effects depend on time and temperatures for TiNi alloys. Seven waiting periods with three different temperature values were applied. Totally 22 experiments were conducted, and the results of the transformation temperatures were obtained for each experiment. Time depended results, especially for 200 °C samples exhibited more stable state than 300 and 400 °C. When the temperature values are considered, a remarkable increase is observed after 200 °C.

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Section: Resultsmentioning

confidence: 78%

Investigation of Thermomechanical Behaviors of Aged Ti55.68Ni44.32 Alloys

Özkul¹,

Canbay²

2018

Anadolu University Journal of Science and Technology-a Applied Sciences and Engineering

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“…This suggests that the new phase is harder than the B2 phase 8 . Previous studies 9 suggest that annealing produces a two-step transformation of the form B2 → R → B19', were R is a phase that forms close to room temperature. This two-step transformation is due to presence of stress fields caused by slip dislocation that act as a barrier to the direct transformation B2 → B19').…”

Section: Resultsmentioning

confidence: 99%

Recovery Mechanisms in a Compressed Ni-Ti Superelastic Alloy

et al. 2017

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The present work studied the influence of annealing on a Ni-Ti alloy submitted to uniaxial compression. The stress-strain curve under compression showed the absence of the Stress-InducedMartensite (SIM) plateau and 42% of remaining austenitic phase (B2). identified by the Electron Backscattered Diffraction (EBSD) technique on a Scanning Electronic Microscope (SEM). Annealing at 150 ºC increased the volume fraction of austenite to 70%. Annealing at 200 ºC reduced the volume fraction of austenite to 33% and increased the classical Vickers hardness and the dynamic elastoplastic hardness. This increase suggests the presence of a phase with higher indentation resistance, which can be the R phase reported in the literature. Annealing at 250 ºC decreased the classical Vickers hardness and the dynamic elastoplastic hardness, probably due to recovery. Annealing at 300 ºC advanced the recovery process and promoted some recrystallization, as suggested by the large standard deviation observed in the hardness results.

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“…The thermoelasticity of SMAs relies on the B2 ↔ 19' martensitic transformation behaviors, which can be influenced by heat treatments and plastic deformations, such as thermal cycling [2], aging treatment [3,4], and cold rolling [5]. Moreover, the martensitic transformation of TiNi SMAs is also affected by the addition of other elements.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermomechanical Treatment on Phase Transformation of the Ti50Ni49W1 Shape Memory Alloy

Huang¹,

Ou²,

Kuo³

et al. 2020

Metals

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The Ti50Ni49W1 alloy has a B2 ↔ 19’ martensitic transformation but slightly lower shape recovery than the Ti50Ni50 alloy. The B19’ martensite structure in the Ti50Ni49W1 has the lattice parameters a = 0.301 nm; b = 0.423 nm; c = 0.472 nm; and β = 97.5°. The hardness increment and transformation temperature depression of Ti50Ni49W1 are greater than those of Ti50Ni50 under the same degree of cold rolling and the same number of thermal cycles; owing to the Ti50Ni49W1; with higher inherent hardness from solidification strengthening of W atoms. Both thermal cycling and cold rolling on Ti50Ni49W1 also promotes R-phase transformation. The effects of thermal cycling and cold rolling on the martensitic transformation temperature (Ms) of the Ti50Ni49W1 alloy follow a linear trend; and the Ms decreased with the hardness.

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Influences of aging and thermomechanical treatments on the martensitic transformation and superelasticity of highly Ni-rich Ti-51.5at.% Ni shape memory alloy

Cited by 18 publications

References 31 publications

Investigation of Thermomechanical Behaviors of Aged Ti55.68Ni44.32 Alloys

Investigation of Thermomechanical Behaviors of Aged Ti55.68Ni44.32 Alloys

Recovery Mechanisms in a Compressed Ni-Ti Superelastic Alloy

Effects of Thermomechanical Treatment on Phase Transformation of the Ti50Ni49W1 Shape Memory Alloy

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