Effects of Hydrogen Charging on the Phase Transformation of Martensitic NiTi Shape Memory Alloy Wires

Snir, Y.; Carl, Matthew; Ley, Nathan A.; Young, Marcus L.

doi:10.1007/s40830-017-0127-y

Cited by 12 publications

(3 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For the exothermic peak corresponding to the austenite-to-martensite phase transformation during cooling in Figure 2(a), the enthalpy DH F decreases while the loss factor increases, as reported in Table 1. A decrease in enthalpy with increasing H content was also observed by Runciman et al (2008) and Snir et al (2017). While the storage modulus decreases for aged materials, it increases with increasing hydrogenation.…”

Section: Resultssupporting

confidence: 76%

Augmentation of low frequency damping via hydrogen-doping in a hybrid shape memory alloy composite

Nagrale

Brown

Bakis

et al. 2021

Journal of Intelligent Material Systems and Structures

View full text Add to dashboard Cite

Carbon fiber reinforced polymer (CFRP) composites hybridized with hydrogen-doped NiTi wires can be used to design structures requiring high stiffness and high damping in the low frequency range, such as helicopter blades. The current work investigates aging and hydrogen-doping for high damping without hydrogen embrittlement. We establish a hydrogenation treatment that (i) results in a response that is repeatable in the martensitic phase and after exposure to composite processing temperatures and (ii) increases the loss factor in NiTi wires by nearly 470%. By embedding H-doped wires exhibiting the highest damping into the interlayers of a [0/±45]s carbon/epoxy laminate at a volume fraction of 0.1, the hybrid NiTi-CFRP composite loss factor increases by 170%. The measured dynamic properties were found to be close to micromechanical predictions based on the properties of the NiTi and CFRP.

show abstract

Section: Resultssupporting

confidence: 76%

Augmentation of low frequency damping via hydrogen-doping in a hybrid shape memory alloy composite

Nagrale

Brown

Bakis

et al. 2021

Journal of Intelligent Material Systems and Structures

View full text Add to dashboard Cite

show abstract

“…Instead, the material revealed a hydrogen-rich “H-strained” B19′ phase which transformed on heating to a B2 phase (hydrogen solid solution) with further hydrogen desorption from the B2 phase. By and large, the temperature intervals of hydrogen-rich “H-strained” B19′ transformation and B2 hydrogen desorption are close to the low- and high-temperature peaks in Figure 4, but any other conclusions need respective thermal desorption data which are not presented in the cited paper [40].…”

Section: Resultsmentioning

confidence: 94%

“…However, in view of available data [40], hydrogenated TiNi alloys with a higher Ti content may have another cause for the low-temperature peak of thermal desorption on heating. According to the data [40], no TiNiH hydride was detected in B19′-phase Ti 50.5 Ni 49.5 (at%) alloy after hydrogenation. Instead, the material revealed a hydrogen-rich “H-strained” B19′ phase which transformed on heating to a B2 phase (hydrogen solid solution) with further hydrogen desorption from the B2 phase.…”

Section: Resultsmentioning

confidence: 99%

The Effect of Hydrogen on Martensite Transformations and the State of Hydrogen Atoms in Binary TiNi-Based Alloy with Different Grain Sizes

et al. 2019

View full text Add to dashboard Cite

The analysis presented here shows that in B2-phase of Ti49.1Ni50.9 (at%) alloy, hydrogenation with further aging at room temperature decreases the temperatures of martensite transformations and then causes their suppression, due to hydrogen diffusion from the surface layer of specimens deep into its bulk. When hydrogen is charged, it first suppresses the transformations B2↔B19′ and R↔B19′ in the surface layer, and when its distribution over the volume becomes uniform, such transformations are suppressed throughout the material. The kinetics of hydrogen redistribution is determined by the hydrogen diffusion coefficient DH, which depends on the grain size. In nanocrystalline Ti49.1Ni50.9 (at%) specimens, DH is three times greater than its value in coarse-grained ones, which is likely due to the larger free volume and larger contribution of hydrogen diffusion along grain boundaries in the nanocrystalline material. According to thermal desorption spectroscopy, two states of hydrogen atoms with low and high activation energies of desorption exist in freshly hydrogenated Ti49.1Ni50.9 (at%) alloy irrespective of the grain size. On aging at room temperature, the low-energy states disappear entirely. Estimates by the Kissinger method are presented for the binding energy of hydrogen in the two states, and the nature of these states in binary hydrogenated TiNi-based alloys is discussed.

show abstract

Effect of Hydrogen Doping on Stress-Induced Martensitic Transformation in a Ti-Ni Shape Memory Alloy

Xiao

Liang

et al. 2019

Metall Mater Trans A

View full text Add to dashboard Cite

Effects of Hydrogen Charging on the Phase Transformation of Martensitic NiTi Shape Memory Alloy Wires

Cited by 12 publications

References 42 publications

Augmentation of low frequency damping via hydrogen-doping in a hybrid shape memory alloy composite

Augmentation of low frequency damping via hydrogen-doping in a hybrid shape memory alloy composite

The Effect of Hydrogen on Martensite Transformations and the State of Hydrogen Atoms in Binary TiNi-Based Alloy with Different Grain Sizes

Effect of Hydrogen Doping on Stress-Induced Martensitic Transformation in a Ti-Ni Shape Memory Alloy

Contact Info

Product

Resources

About