Effects of interactions between dislocations and/or vacancies and He atoms on mechanical property changes in Ni

Xu, Qiu; Yamasaki, Hideo; Sugiura, Yusaku; Sato, Koichi; Yoshiie, T.

doi:10.1016/j.msea.2013.08.011

Cited by 12 publications

(8 citation statements)

References 14 publications

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“…The parameters employed in these calculations are shown in Table 3 . D H was evaluated to be 2.8 × 10 9 nm 2 /s according to ref 11 . The calculation results are shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The yield stress and tensile strength also increased slightly. Unexpectedly, it was reported that helium trapped by the dislocations improves the ductility of iron and nickel 9 – 11 . Although the mechanism for improving the ductility of iron and nickel by helium is still not clear, it is suggested that helium delays the aggregation of vacancies produced during sample tension, resulting in an increase in elongation.…”

Section: Discussionmentioning

confidence: 99%

“…Recently, it was reported that helium trapped by dislocations in iron and nickel increases the total elongation of these metals 9 – 11 . These experimental results were contrary to expectation.…”

Section: Introductionmentioning

confidence: 99%

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Novel Methods for Prevention of Hydrogen Embrittlement in Iron

2017

Sci Rep

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Iron is the most widely used metal in the world. However, hydrogen embrittlement in steels—iron based alloys—is an important issue related to the safety of our infrastructure, such as railroads and bridges. Therefore, the prevention of hydrogen embrittlement in steels is necessary. In the present study, we demonstrate two novel methods for the prevention of hydrogen embrittlement in iron: one involves the low-energy implantation of helium, which is usually an element harmful to metals, into iron, the other is inducing damage to the iron surface by ion irradiation. In general, irradiation with high-energy particles leads to metal brittleness. In the former method, the driving force for hydrogen embrittlement in iron is weakened, in the latter method, hydrogen diffusion in iron is prevented because of trapping of hydrogen atoms in the vacancies produced by the irradiation. As a result, hydrogen embrittlement in iron was suppressed by both methods.

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“…The parameters employed in these calculations are shown in Table 3 . D H was evaluated to be 2.8 × 10 9 nm 2 /s according to ref 11 . The calculation results are shown in Fig.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Novel Methods for Prevention of Hydrogen Embrittlement in Iron

2017

Sci Rep

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“…Helium ion implantation can improve the mechanical properties of metal materials containing dislocation defects, i.e. the increase in strength and elongation of Ni [26]. Thus, understanding the physical origins of helium atoms trapping and its interaction with dislocations in metals remains an important topic in the nuclear fusion research.…”

Section: Nuclear Fusionmentioning

confidence: 99%

Helium self-trapping and diffusion behaviors in deformed 316L stainless steel exposed to high flux and low energy helium plasma

et al. 2018

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A large number of dislocation networks were introduced in to 316L stainless steel by cold rolling. Subsequently, low energy (40 eV) helium ions were implanted by exposing the steel to helium plasma. Thermal desorption and positron annihilation spectroscopy were used to study the behavior of helium in the presence of dislocations, with emphasis on helium self-trapping and migration behaviors. Helium desorption behaviour from different helium trapping states was measured by the thermal desorption spectroscopy. Most of the helium desorbed from the HemVn clusters, and the corresponding desorption peak is located at ~650 K. The desorption peak from helium-dislocation clusters (HemD) is at approximately 805 K. The effect of annealing on the defect evolution was investigated by positron annihilation spectroscopy. For the specimen exposed to helium plasma without displacement damage, the increment of S parameter meant the existence of helium self-trapping behavior (HemVn). Helium atoms could diffuse two to three orders of magnitude deeper than the implantation depth calculated by SRIM. The diffusing helium atoms were gradually trapped by dislocation lines and formed HemD. Elevated temperatures enhance the self-trapping behavior and cause helium atoms to dissociate/desorb from the HemVn clusters, increasing the S parameters at 473–673 K. The gradual recovery of vacancies in the HemVn clusters decreased the S parameter above 673 K.

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“…[10] Xu et al reported that He implantation increases the ultimate tensile strength and ductility of Ni samples with only dislocations. [11,12] A better understanding of the microscopic mechanisms of interactions between He and defects in metals is essential for the nuclear and materials industry.…”

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confidence: 99%

Atomistic Simulations of the Effect of Helium on the Dissociation of Screw Dislocations in Nickel

Wang

Zhang

et al. 2016

Chinese Phys. Lett.

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The interactions of He with dissociated screw dislocations in face-centered-cubic (fcc) Ni are investigated by using molecular dynamics simulations based on an embedded-atom method model. The binding and formation energies of interstitial He in and near Shockley partial cores are calculated. The results show that interstitial He atoms at tetrahedral sites in the perfect fcc lattice and atoms occupying sites one plane above or below one of the two Shockley partial cores exhibit the strongest binding energy. The attractive or repulsive nature of the interaction between interstitial He and the screw dislocation depends on the relative position of He to these strong binding sites. In addition, the effect of He on the dissociation of screw dislocations are investigated. It is found that He atoms homogeneously distributed in the glide plane can reduce the stacking fault width.

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Effects of interactions between dislocations and/or vacancies and He atoms on mechanical property changes in Ni

Cited by 12 publications

References 14 publications

Novel Methods for Prevention of Hydrogen Embrittlement in Iron

Novel Methods for Prevention of Hydrogen Embrittlement in Iron

Helium self-trapping and diffusion behaviors in deformed 316L stainless steel exposed to high flux and low energy helium plasma

Atomistic Simulations of the Effect of Helium on the Dissociation of Screw Dislocations in Nickel

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