Article
Chemistry, Physical
Zhilin Zheng, Min Yi, Shuai Wang
Summary: This study reveals that the tetrahedral trapping site for hydrogen in body-centered cubic iron is unstable under elastic stress field, while the octahedral site is more stable and preferred. The abnormal trapping phenomenon is influenced by the hydrogen-dislocation elastic interaction and zero-point quantum vibration. The motion of dislocations can change the trapping position of hydrogen atoms and promote premature failure in a hydrogen environment.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Materials Science, Multidisciplinary
D. Smirnova, S. Starikov
Summary: We conducted a classical atomistic study on hydrogen diffusion in a-Fe and y-Fe in the presence of grain boundaries, surfaces, or vacancies. Defects of different complexion, which act as pronounced traps for hydrogen, play a significant role in the diffusion mechanisms related to hydrogen embrittlement. By using a recently developed interatomic potential, we estimated the potential impact of these defects on hydrogen diffusion. Our results showed that the interaction between hydrogen and defects strongly depends on the host Fe structure, with grain boundaries and surfaces accelerating diffusion in fcc Fe but not in bcc Fe, and the binding of hydrogen with a mono-vacancy leading to a reduction in vacancy migration rate for both lattice types. We also discussed the equilibrium hydrogen concentrations at grain boundaries and the role of hydrogen located in grain boundaries in the overall hydrogen flux in a polycrystal.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Zheng Wang, Xiaoming Shi, Xu-Sheng Yang, Wangqiang He, San-Qiang Shi, Xingqiao Ma
Summary: The local distribution of hydrogen atoms has significant impacts on hydrogen embrittlement, affecting fracture behavior and mechanical properties of materials. Adsorbed hydrogen atoms near crack surfaces can suppress fractures through stress relaxation and lead to microvoid-coalescence fracture.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Materials Science, Multidisciplinary
Yu Chen, Yin Zhang, Dengke Chen
Summary: Hydrogen-dislocation interactions play a crucial role in understanding hydrogen embrittlement phenomena in metallic materials. Through calculations and simulations, the effects of hydrogen atoms on dislocation nucleation and shear stress are revealed.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Engineering, Mechanical
Lanxi Feng, Xiaoqing Zhang, Wanghui Li, Meizhen Xiang, Xiaohu Yao
Summary: Hydrogen embrittlement in metals has long been a concern, but the fundamental mechanisms in dynamic events are not well understood. Atomic simulations reveal the anisotropic effects of hydrogen atoms on spall strength in different crystal orientations. Hydrogen atoms prevent phase transition and enhance spall strength in [100] crystal orientation, while in [111] crystal orientation, hydrogen atoms promote dislocation formations and lower spall strength. In nanocrystalline samples, hydrogen atoms slightly increase spall strength by disturbing grain boundaries. This work provides insights into hydrogen effects on metals under dynamic loading, benefiting materials and mechanics research communities.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2023)
Article
Chemistry, Physical
Mehmet Fazil Kapci, J. Christian Schoen, Burak Bal
Summary: Investigations on dislocation mobility in the presence of hydrogen revealed that hydrogen decreases dislocation velocity and induces some localization. Additionally, hydrogen accumulation in the grain boundary suppresses new grain formation, leading to material hardening and potentially initiating brittle fracture points.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Materials Science, Multidisciplinary
Hailin Cao, Shuai Wang
Summary: In this study, the influence of internal hydrogen on the plastic deformation ahead of a crack tip in tungsten foil was investigated. The presence of hydrogen resulted in the formation of an intermittent plastic zone composed of dislocation tangles and a dislocation network with an L-square shape. The L-square dislocation structure tended to move along the crack propagation direction, indicating a competition between H-modified dislocation motion and H-induced decohesion.
Article
Materials Science, Multidisciplinary
Yuanyuan Zheng, Ping Yu, Lin Zhang
Summary: One way to assess the validity of elasticity is by using atomic simulations to study the interactions between hydrogen (H) and edge dislocations in bcc iron. The simulations show that strong binding between H and the dislocation occurs at the dislocation core and on the slip plane, suggesting the formation of high H concentrations along the slip plane. The study also reveals that interstitial H interacts not only with hydrostatic stress but also with shear stresses generated by the dislocation, particularly on the slip plane.
Article
Physics, Applied
Alena Uhnakova, Anna Machova, Michaela Janovska, Martin Sevcik, Jan Stefan, Petr Hora, Jaroslav Capek, Pavel Lejcek
Summary: This paper presents an experimental and 3D atomistic study on the influence of loading rate on fracture toughness in dilute Fe-Si alloys and bcc iron. The results show a decrease in fracture toughness at the highest loading rate, which is in agreement with previous experimental findings. Molecular dynamics simulations reveal that the emission of blunting dislocations from the crack is the most difficult under the highest loading rate, leading to a reduced fracture toughness at the atomic level.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Metallurgy & Metallurgical Engineering
Ryosuke Matsumoto, Sunday T. Oyinbo, Mugilgeethan Vijendran, Shinya Taketomi
Summary: Explaining the effect of hydrogen on dislocation mobility is important for understanding hydrogen-related fracture phenomena. This research conducted molecular dynamics simulations to study the impact of hydrogen on edge dislocation motion in alpha-iron. It was found that hydrogen transitioned from pinning to dragging at a dislocation speed of around 0.1 m/s. At a reduced dislocation velocity of 0.01 m/s, hydrogen followed dislocation motion with small jumps in the dislocation core. The required stress for dislocation migration at 0.01 m/s was 400 MPa, even at lower hydrogen concentrations in a gaseous hydrogen environment. The effect of hydrogen on the required shear stress for dislocation glide became negligible as temperature increased.
ISIJ INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Masato Wakeda, Takahito Ohmura
Summary: This study evaluates the resistance for dislocation transmission across tilt/twist low-angle grain boundaries (LAGBs) and found that the twist LAGB is a stronger obstacle compared to the tilt LAGB. The barrier effect of the grain boundary (GB) on the transmission is stronger for the screw component than for the edge component. The dominant factors of the GB-strengthening effect in LAGB are the incident lattice dislocation type, the structure of GB dislocations, and dislocation-dislocation reactions.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Ehsan Norouzi, Reza Miresmaeili, Hamid Reza Shahverdi, Mohsen Askari-Paykani, Laura Maria Vergani
Summary: The study investigated the effect of plastic deformations on the hydrogen embrittlement of TRIP steel. In situ tensile tests revealed that the total elongation loss increased by 36.8% with increasing hydrogen current density. EBSD observation showed that hydrogen charging decreased stacking fault energy, leading to the formation of more a0-martensite. The formation of a0-martensite and increased dislocation density resulted in the reversible trap sites.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Weijian Chen, Weiyan Zhao, Pengfei Gao, Feng Li, Shuang Kuang, Yu Zou, Zhengzhi Zhao
Summary: This study investigates the interaction between dislocations, precipitates, and hydrogen atoms in high strength hot-stamped steel and its effect on hydrogen embrittlement (HE) resistance. The results show that inhibiting the diffusion and aggregation of hydrogen atoms can effectively improve the resistance to HE. Additionally, dispersed V-rich (Ti, V)C precipitates play a positive role in enhancing the resistance to HE.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Chemistry, Physical
Hiroshi Kakinuma, Saya Ajito, Tomohiko Hojo, Motomichi Koyama, Sachiko Hiromoto, Eiji Akiyama
Summary: In this study, the distribution of hydrogen entering an Fe sheet under a droplet of NaCl solution was successfully visualized using a hydrogenochromic sensor. The entry of hydrogen was initially difficult to confirm, but became observable as the corrosion progressed, with the preferential entry site corresponding to the rust-formed area. The study postulates that the decrease in pH due to hydrolysis reactions of Fe ions under the rust promotes the entry of hydrogen.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2022)
Article
Chemistry, Physical
A. Drexler, C. Bergmann, G. Manke, V Kokotin, K. Mraczek, S. Leitner, M. Pohl, W. Ecker
Summary: Hydrogen embrittlement is a critical issue in the application of advanced high strength steel sheets, especially in severe plastic deformation at punched edges. By investigating two industrial AHSS, it was found that hydrogen accumulates in the shear affected zone, leading to the development of a simplified two-zone model to estimate local hydrogen concentration in punched AHSS sheets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Ryosuke Matsumoto, Masayuki Uranagase
MATERIALS TRANSACTIONS
(2015)
Article
Materials Science, Multidisciplinary
Koji Hagihara, Masahito Honnami, Ryosuke Matsumoto, Yoshihiro Fukusumi, Hitoshi Izuno, Michiaki Yamasaki, Takuya Okamoto, Takayoshi Nakano, Yoshihito Kawamura
MATERIALS TRANSACTIONS
(2015)
Article
Materials Science, Multidisciplinary
Masayuki Uranagase, Ryosuke Matsumoto
COMPUTATIONAL MATERIALS SCIENCE
(2016)
Article
Materials Science, Multidisciplinary
Masayuki Uranagase, Ryosuke Matsumoto
COMPUTATIONAL MATERIALS SCIENCE
(2016)
Article
Engineering, Mechanical
R. Matsumoto, M. Kubota, N. Miyazaki
EXPERIMENTAL TECHNIQUES
(2016)
Article
Mechanics
Pengyu Liu, Ryosuke Matsumoto
ENGINEERING FRACTURE MECHANICS
(2019)
Article
Materials Science, Multidisciplinary
Ryosuke Matsumoto, Shinya Taketomi
COMPUTATIONAL MATERIALS SCIENCE
(2020)
Article
Materials Science, Multidisciplinary
Kazuhito Fukuda, Akihiro Tojo, Ryosuke Matsumoto
MATERIALS TRANSACTIONS
(2020)
Article
Materials Science, Multidisciplinary
Shuki Nagase, Ryosuke Matsumoto
MATERIALS TRANSACTIONS
(2020)
Article
Materials Science, Multidisciplinary
Ken-ichi Ebihara, Yuri Sugiyama, Ryosuke Matsumoto, Kenichi Takai, Tomoaki Suzudo
Summary: The study found that under the conditions of applied strain and hydrogen charging, a unique shoulder peak appeared in the thermal desorption spectra of iron samples, potentially caused by hydrogen atoms released by vacancies. By simulating the experimental spectra using a model, researchers speculated that the diffusion rate of V-2 and V-3 clusters may be slower, and that strain and hydrogen charging concurrently may lead to the generation of vacancy clusters.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2021)
Article
Metallurgy & Metallurgical Engineering
Shuki Nagase, Ryosuke Matsumoto
Summary: The study evaluated the diffusion coefficients of hydrogen in body-centered cubic iron using density functional theory and small-polaron theory calculations. It was found that the diffusion coefficient changes with temperature and volumetric strain, with the change occurring at around 400 K. Tunneling between ground states dominantly contributes to diffusion at lower temperatures, while tunneling between low excited states contributes dominantly at high temperatures.
ISIJ INTERNATIONAL
(2021)
Article
Metallurgy & Metallurgical Engineering
Ryosuke Matsumoto, Sunday T. Oyinbo, Mugilgeethan Vijendran, Shinya Taketomi
Summary: Explaining the effect of hydrogen on dislocation mobility is important for understanding hydrogen-related fracture phenomena. This research conducted molecular dynamics simulations to study the impact of hydrogen on edge dislocation motion in alpha-iron. It was found that hydrogen transitioned from pinning to dragging at a dislocation speed of around 0.1 m/s. At a reduced dislocation velocity of 0.01 m/s, hydrogen followed dislocation motion with small jumps in the dislocation core. The required stress for dislocation migration at 0.01 m/s was 400 MPa, even at lower hydrogen concentrations in a gaseous hydrogen environment. The effect of hydrogen on the required shear stress for dislocation glide became negligible as temperature increased.
ISIJ INTERNATIONAL
(2022)
Article
Materials Science, Multidisciplinary
Mugilgeethan Vijendran, Ryosuke Matsumoto
Summary: Plastic deformation and hydrogen presence enhance the concentration of vacancy-type defects in alpha-iron, leading to the formation of planar vacancy clusters (VCs) and prismatic dislocation loops (PDLs). The formation and conversion of VCs and PDLs influences the mechanical properties of iron-based materials. A quantitative energy barrier for the transition between nano-sized PDLs and VCs has been established, showing that VCs with a cluster size of more than 19 vacancies easily nucleate into PDLs in alpha-iron.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Sunday Temitope Oyinboa, Suraj Singhanekab, Ryosuke Matsumoto
Summary: This study used molecular dynamics to investigate the slip transfer behaviors of edge and screw dislocations in magnesium at basal/prismatic grain boundaries. The results show that the initial basal dislocation migrates towards the grain boundary, interacts with the boundary, and changes into a prismatic dislocation. The critical resolved shear stress for the transmutation of basal screw dislocations is higher than edge dislocations.