Strong interactions between hydrogen in solid solution and stress-induced martensite transformation of Ni–Ti superelastic alloy

Yokoyama, K.; Hirata, Yuki; Inaba, Toshiaki; Mutoh, Kenichiro; Sakai, Jun–ichi

doi:10.1080/09500839.2016.1262561

Cited by 14 publications

(6 citation statements)

References 30 publications

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“…Immediately after immersion, hydrogen presumably exists as hydrogen in solid solution or hydride, as reported previously [41][42][43][44][45]. Hydride does not necessarily dominate hydrogen embrittlement behaviour and decomposes during aging even at room temperature [41][42][43][44][45]. The desorption behaviour in the present study was changed by the concentrations of NaHCO 3 and H 2 O 2 and was not always the same as that reported previously [9].…”

Section: Inhibition Of Hydrogen Absorptionsupporting

confidence: 83%

“…The hydrogen desorption behaviour reflects hydrogen states including hydrogen in solid solution, hydrogen trapped at defects and hydride. Immediately after immersion, hydrogen presumably exists as hydrogen in solid solution or hydride, as reported previously [41 45]. Hydride does not necessarily dominate hydrogen embrittlement behaviour and decomposes during aging even at room temperature [41 45].…”

Section: Resultsmentioning

confidence: 65%

“…Hydrogen absorption is enhanced owing to the high hydrogen solubility limit and diffusion rate in the martensite phase [41]. Moreover, hydrogen absorption is further enhanced by dynamic lattice changes due to transformation [44,45,[48][49][50][51]. Nevertheless, it is likely that the present countermeasure for hydrogen absorption is effective because of the inhibition of hydrogen evolution, although corrosion resistance somewhat decreases in the presence of the martensite phase or during martensite transformation.…”

Section: Inhibition Of Hydrogen Absorptionmentioning

confidence: 99%

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Countermeasure for corrosion and hydrogen embrittlement of Ni-Ti superelastic alloy in acidic fluoride solution by adding sodium bicarbonate and hydrogen peroxide

Yamaguchi

Yokoyama

2021

Corrosion Engineering, Science and Technology

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Development of countermeasure for corrosion and hydrogen embrittlement of Ni-Ti superelastic alloy in an acidulated phosphate fluoride (APF) solution has been attempted by adding NaHCO 3 and H 2 O 2 to the solution. Upon addition of only 0.001 M NaHCO 3 to a 0.2% APF solution, almost no changes in corrosion current density and corrosion potential are observed. With an increasing NaHCO 3 concentration up to 0.01 M, the corrosion current density substantially decreases and the corrosion potential slightly shifts in the noble direction. The corrosion loss significantly decreases and hydrogen absorption is slightly inhibited. Upon the combined addition of 0.01 M NaHCO 3 and 0.001 M H 2 O 2 , the corrosion current density is lowest and the corrosion potential shifts in the noble direction. The corrosion and hydrogen absorption are substantially inhibited. The present study clearly indicates that the combined addition is exceptionally effective as a simultaneous countermeasure for corrosion and hydrogen embrittlement of the alloy.

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Section: Inhibition Of Hydrogen Absorptionsupporting

confidence: 83%

Section: Resultsmentioning

confidence: 65%

Section: Inhibition Of Hydrogen Absorptionmentioning

confidence: 99%

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Countermeasure for corrosion and hydrogen embrittlement of Ni-Ti superelastic alloy in acidic fluoride solution by adding sodium bicarbonate and hydrogen peroxide

Yamaguchi

Yokoyama

2021

Corrosion Engineering, Science and Technology

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“…In the tensile test, the dynamic interactions between hydrogen and deformation often markedly affect hydrogen embrittlement. 4,[15][16][17][18][19][20] These interactions enhance the nucleation of defects. 4,[15][16][17][18] Ferritic steel is suitable for evaluation of the effects of the interactions on hydrogen embrittlement because of its low density of initial defects.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen Embrittlement Induced by Hydrogen Charging during Deformation of Ultra-high Strength Steel Sheet Consisting of Ferrite and Nanometer-sized Precipitates

Takashima¹,

Han

Yokoyama

et al. 2019

ISIJ Int.

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The hydrogen embrittlement behavior of an ultra-high strength steel sheet consisting of ferrite and nanometer-sized precipitates has been investigated by a tensile test and sustained tensile-loading test. The amount of absorbed hydrogen of the present ferritic steel is significantly larger than that of the conventional martensitic steels. Hydrogen thermal desorption analysis indicates that a large amount of diffusible hydrogen exists and the nanometer-sized precipitates act as trap sites of hydrogen. In a tensile test in air after the saturation amount of hydrogen charging, the fracture strain decreases slightly. However, in a tensile test during hydrogen charging, the fracture strain decreases markedly despite a small amount of absorbed hydrogen, and the morphology of the fracture surface exhibits a unique brittle mode. Upon prestraining, the saturation amount of hydrogen is more than doubled and the tensile properties deteriorate further. In the sustained tensile-loading test during hydrogen charging, no delayed fracture occurs even under high applied stress. No effects of hydrogen charging on stress relaxation are observed. The results of the present study imply that the increase in the hydrogen content enhances the degradation of tensile properties, but the hydrogen content is not necessarily an index of the hydrogen embrittlement of the ferritic steel. The dynamic interactions between hydrogen and deformation, and particularly, the continuous interactions during hydrogen charging, play important roles in hydrogen embrittlement.

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“…Several experimental works have focused on the physical aspect of NiTi shape memory alloys (SMA), for example, the fatigue performance (Casciati et al, 2017; Casciati and Marzi, 2011) and the damping properties (Torra et al, 2014). Concerning hydrogen, it has shown important impacts on the mechanical behavior of the NiTi alloys during tensile tests, such as embrittlement and sudden fracture (Gamaoun et al, 2011; Yokoyama et al, 2016). In addition, a heightening in the transformation stress and a decrease in its strain have been noticed since the hydrogen obstructs some austenitic NiTi lattices to transform to the martensite phase (Elkhal Letaief et al, 2016; Gamaoun and Hassine, 2014).…”

Section: Introductionmentioning

confidence: 99%

Finite element analysis of hydrogen effects on superelastic NiTi shape memory alloys: Orthodontic application

Letaief

Fathallah

Hassine

et al. 2018

Journal of Intelligent Material Systems and Structures

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Thanks to its greater flexibility and biocompatibility with human tissue, superelastic NiTi alloys have taken an important part in the market of orthodontic wires. However, wire fractures and superelasticity losses are notified after a few months from being fixed in the teeth. This behavior is due to the hydrogen presence in the oral cavity, which brittles the NiTi arch wire. In this article, a diffusion-mechanical coupled model is presented while considering the hydrogen influences on the NiTi superelasticity. The model is integrated in ABAQUS finite element software via a UMAT subroutine. Additionally, a finite element model of a deflected orthodontic NiTi wire within three teeth brackets is simulated in the presence of hydrogen. The numerical results demonstrate that the force applied to the tooth drops with respect to the increase in the hydrogen amount. This behavior is attributed to the expansion of the NiTi structure after absorbing hydrogen. In addition, it is shown that hydrogen induces a loss of superelasticity. Hence, it attenuates the role of the orthodontic wire on the correction tooth malposition.

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Strong interactions between hydrogen in solid solution and stress-induced martensite transformation of Ni–Ti superelastic alloy

Cited by 14 publications

References 30 publications

Countermeasure for corrosion and hydrogen embrittlement of Ni-Ti superelastic alloy in acidic fluoride solution by adding sodium bicarbonate and hydrogen peroxide

Countermeasure for corrosion and hydrogen embrittlement of Ni-Ti superelastic alloy in acidic fluoride solution by adding sodium bicarbonate and hydrogen peroxide

Hydrogen Embrittlement Induced by Hydrogen Charging during Deformation of Ultra-high Strength Steel Sheet Consisting of Ferrite and Nanometer-sized Precipitates

Finite element analysis of hydrogen effects on superelastic NiTi shape memory alloys: Orthodontic application

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