Effect of elements addition on hydrogen permeability and ductility of Nb40Ti18Zr12Ni30 alloy

Tang, Hui Xiang; Ishikawa, Kazuhiro; Aoki, Kiyoshi

doi:10.1016/j.jallcom.2007.06.116

Cited by 12 publications

(7 citation statements)

References 12 publications

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“…The microstructure of non-equimolar Nb40Ni25Ti18Zr12Co5 (Figure 3b) high entropy alloy is represented by a light-grey contrasted Nb-rich BCC phase with dendritic structure (region 3) embedded in dark-grey contrasted matrix of B2-Ni(Ti, Zr) and B2-CoZr phases (region 4). Similar morphology and phases were observed by Tang et al for Nb40Ti18Zr12Ni30 alloy [15]. Additionally, light-grey globular inclusions with high concentration of Nb (31 at.%) were detected in region 5.…”

Section: Microstructure and Phase Compositionsupporting

confidence: 87%

“…The addition of Co is effective in suppressing hydrogen embrittlement of Ni-Nb-Zr-Co alloy [14]. Tang et al investigated multicomponent Nb 40 Ti 18 Zr 12 Ni 25 M 5 (M = Al, Co, Cu, Pd) and showed that the Nb 40 Ti 18 Zr 12 Ni 25 Co 5 alloy had the highest permeability of 3.8 × 10 −8 (molH 2 m −1 s −1 Pa −0.5 ), higher than that for Pd 0.23 Ag 0.77 alloy, with a permeability of 1.6 × 10 −8 (molH 2 m −1 s −1 Pa −0.5 ), while maintaining stable performance [15].…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Hydrogen Permeability of Nb-Ni-Ti-Zr-Co High Entropy Alloys

et al. 2022

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Hydrogen separation membranes are one of the most promising technologies for hydrogen purification. The development of high-entropy alloys (HEAs) for hydrogen separation membranes is driven by a “cocktail effect” of elements with different hydrogen affinities to prevent hydride formation and retain high permeability due to the single-phase BCC structure. In this paper, equimolar and non-equimolar Nb-Ni-Ti-Zr-Co high entropy alloys were fabricated by arc melting. The microstructure and phase composition of the alloys were analyzed by scanning electron microscopy and X-ray diffraction, respectively. The hydrogen permeation experiments were performed at 300–500 °C and a hydrogen pressure of 4 bar. In order to estimate the effect of composition and lattice structure on hydrogen location and diffusivity in Nb-Ni-Ti-Zr-Co alloy, ab initio calculations of hydrogen binding energy were performed using virtual crystal approximation. It was found that Nb-enriched and near equimolar BCC phases were formed in Nb20Ni20Ti20Zr20Co20 HEA while Nb-enriched BCC and B2-Ni(Ti, Zr) were formed in Nb40Ni25Ti18Zr12Co5 alloy. Hydrogen permeability tests showed that Nb20Ni20Ti20Zr20Co20 HEA shows lower activation energy and higher permeability at lower temperatures as well as higher resistance to hydrogen embrittlement compared to Nb40Ni25Ti18Zr12Co5 alloy. The effect of composition, microstructure and hydrogen binding energies on permeability of the fabricated alloys was discussed.

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Section: Microstructure and Phase Compositionsupporting

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Microstructure and Hydrogen Permeability of Nb-Ni-Ti-Zr-Co High Entropy Alloys

et al. 2022

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“…In particular, in hydrogen-separable membranes, the activation energy for hydrogen permeation is a crucial parameter affecting the hydrogen permeability [8,9]. The activation energy for hydrogen permeation is defined as shown in Eq.…”

Section: Introductionmentioning

confidence: 99%

Relationship between activation energy for hydrogen permeation and hydrogen permeation properties of amorphous Cu50Zr50 and Cu65Zr35 membranes

Park¹,

Ahn²,

Seok³

et al. 2011

Intermetallics

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“…mechanically sealed with copper gaskets, these alloys must have at least some ductility. Most simply, a material that can be broken easily by hammering is qualitatively defined as brittle [32][33][34], while non-broken materials are defined as ductile.…”

Section: Ductilitymentioning

confidence: 99%

“…This alloy system exhibits high ductility for fabrication of thin membranes and high tolerance to hydrogen embrittlement, but the hydrogen permeability is not quite satisfactory. It is found that appropriate substitution of Ti by Zr can induce a much higher hydrogen permeability (because of the higher hydrogen affinity of Zr than that of Ti) and comparable other properties [32,33]. Nevertheless, excessive addition of Zr leads to low ductility and serious hydrogen embrittlement due to the microstructural change and the inappropriately high hydrogen solubility [34].…”

Section: Introductionmentioning

confidence: 99%