Article
Nanoscience & Nanotechnology
Huan Zhang, Yangxin Li, Zhigang Ding, Tian Xie, Ruixue Liu, Yuliang Li, Dezhi Zhang, Qingchun Zhu, Xiaoqing Shang, Xiaoqin Zeng
Summary: By studying a high strain rate compressed Mg-Y alloy, a new twin-like {33 (3) over bar4} tilt boundary structure and its formation mechanism were discovered, providing a new insight for the design of new high-performance Mg alloys.
SCRIPTA MATERIALIA
(2021)
Article
Nanoscience & Nanotechnology
Yi-Jia Li, Yuan Fang, Cheng Wang, Zhen-Ming Hua, Yipeng Gao, Min Zha, Hui-Yuan Wang
Summary: The study discovered that twin boundary pinning is a new hardening mechanism in Mg-2Zn-0.5Ca alloy during bake-hardening, enhancing the strength-ductility synergy. The co-segregation of Zn and Ca atoms at twin boundaries effectively suppresses crack propagation, improving the material's ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Zhifeng Huang, Jian-Feng Nie
Summary: This study investigates the interaction of hydrogen with different alloying elements in magnesium alloys at a specific twin boundary, revealing that hydrogen prefers to bond with certain solute elements. These interactions can either enhance or weaken the cohesion of the twin boundary, showcasing the importance of understanding how hydrogen embrittlement occurs in magnesium alloys.
Article
Materials Science, Multidisciplinary
Risheng Pei, Yongchun Zou, Muhammad Zubair, Daqing Wei, Talal Al-Samman
Summary: This study investigates the synergistic effect of various alloying elements on the texture and microstructure evolution in magnesium alloys. The results demonstrate that adjusting the precipitation and solute segregation can lead to desired texture modifications.
Article
Nanoscience & Nanotechnology
Zhi Zhang, Jinghuai Zhang, Jinshu Xie, Shujuan Liu, Yuying He, Ru Wang, Daqing Fang, Wei Fu, Yunlei Jiao, Ruizhi Wu
Summary: The addition of trace Sm can significantly increase the grain boundary segregation concentration in the dilute Mg-Zn-Ca-Mn alloy, improve its yield strength, inhibit grain growth during annealing, and contribute to the design of advanced Mg alloys.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Zhen-Ming Hua, Cheng Wang, Tian-Shuai Wang, Chunfeng Du, Shen-Bao Jin, Gang Sha, Yipeng Gao, Hai -Long Jia, Min Zha, Hui -Yuan Wang
Summary: This study demonstrates that cyclic deformation of a Mg alloy at room temperature can significantly increase the yield strength while only slightly reducing the elongation to failure. The strength improvement is mainly attributed to the formation of high-density solute clusters. This work provides new insights into the strengthening mechanisms and has important implications for the development of Mg alloys with high strength-ductility synergy.
Article
Chemistry, Multidisciplinary
Qiaoyun Tang, Feng Zhang, Youran Zhi, Fengtian Li, Deyong Wang, Liu Yang
Summary: Using molecular dynamics simulation, nanoindentation simulation was conducted on nanotwin Cu-Ag alloys with different gradient distribution structures and twin spacing. The study focused on the mechanical properties and deformation mechanism of nanotwin Cu-Ag alloys with a grain size of 15 nm. The results revealed that twin spacing and solute atom gradient segregation structure have significant effects on the mechanical properties of the alloy, with dislocations and stacking faults more likely to occur in grains with thicker solute concentrations and larger twin boundary spacing.
JOURNAL OF NANOPARTICLE RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Dinh-Quan Doan, Anh-Son Tran, Ngoc-Chien Vu
Summary: The nanoindentation response of FeCoCrNiCu high-entropy alloy was studied through molecular dynamics simulation. Various grain sizes and twin lamellae thicknesses were found to significantly affect the mechanical characteristics and plastic deformation. The study revealed an inverse Hall-Petch effect in the relationship between material strength, grain size, and twin lamellae thickness. The presence of grain boundaries and twin boundaries affected atom movement and resulted in asymmetrical dispersion of atomic displacement vectors during deformation. The results also showed that pile-up height increased with grain size and decreased with twin lamellae spacing. Microstructural evolution indicated that grain rotation and grain boundary movement were dominant mechanisms in deformation with grain size reduction. Dislocation nucleation at the intersections of twin and grain boundaries also significantly affected plastic deformation, with dislocation density increasing with grain size and twin lamellae thickness.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Nanoscience & Nanotechnology
Mingzhe Bian, Xinsheng Huang, Yasumasa Chino
Summary: In the solution treated state, Ag and Ca atoms segregate to grain boundaries, promoting the early formation of GB precipitates compared to the grain interior. Prolonged aging results in the growth of GB precipitates, which serve as preferred initiation sites for microcracks.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Nithin Baler, Akshat Godha, Surendra Kumar Makineni
Summary: Discontinuous precipitation (DP) reactions are significant solid-state phenomena that occur during grain boundary migration in engineering alloys. This study shows atomic-scale compositional analysis during recrystallization in a multicomponent alloy, revealing evidence of bulk/lattice diffusion in a precipitate-free buffer zone and solute segregations at local interfaces, which help determine the rate-limiting solutes for DP reaction kinetics.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Xuebing Liu, Di Zhang, Hui Wang, Yu Yan, Xinfang Zhang
Summary: In this study, a novel manipulation pathway using pulsed electric field (PEC) was explored to control grain boundary structure and improve corrosion resistance in age-hardening aluminum alloys. The calculated atomic diffusion results showed that PEC can stimulate atomic diffusion by decreasing the energy required, inhibiting the formation of continuous distribution of grain boundary precipitates and solute depletion zone. This significantly enhanced the corrosion resistance.
Article
Materials Science, Multidisciplinary
Qianhua Yang, Chun Xue, Zhibing Chu, Yugui Li, Lifeng Ma
Summary: In this study, the uniaxial compression process of AZ31 magnesium alloy with different solute atom content was simulated using molecular dynamics method. The research found that solute atoms can inhibit grain refinement, improve plastic strength, and change lattice distortion. Additionally, the direction of FCC structure diffusion and the generation of Shockley partial dislocations were also observed.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2021)
Review
Metallurgy & Metallurgical Engineering
Yuan Yue, Jian Wang, Jian-Feng Nie
Summary: This paper reviews the interactions between deformation twins and lattice defects in magnesium and its alloys. It covers interactions between twin boundaries and solute atoms, twin-dislocation interactions, and twin-twin interactions. The resulting structures, such as twin-twin junctions and tension-tension double twins, are discussed in detail. The review also highlights remaining research issues and provides suggestions for future work in this area.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Nanoscience & Nanotechnology
J. Zuo, T. Nakata, C. Xu, Y. P. Xia, H. L. Shi, X. J. Wang, G. Z. Tang, W. M. Gan, E. Maawad, G. H. Fan, S. Kamado, L. Geng
Summary: A high strength dilute Mg-0.8Al-0.1Ca-0.6Mn alloy wire was successfully developed by hot drawing, with the high strength attributed to the ultra-fine DRXed grains, coarse elongated unrecrystallized grains with dense dislocations, and nano sized Al2Ca and Al-Mn precipitates dispersed in the alloy wire.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Crystallography
Boris Straumal, Natalya Khrapova, Aleksandr Druzhinin, Kristina Tsoy, Gregory Davdian, Valery Orlov, Gregory Gerstein, Alexander Straumal
Summary: Modern magnesium-based alloys are widely used in various industries and medical field for their exceptional combination of light weight, strength, and plasticity. This study discovered that the grain boundary wetting phenomena of magnesium/magnesium can strongly influence the mechanical properties of the material.
Article
Materials Science, Multidisciplinary
Alok Singh, Takanobu Hiroto, Machiko Ode, Hiroyuki Takakura, Karel Tesar, Hidetoshi Somekawa, Toru Hara
Summary: The precipitation of a stable quasicrystalline i-phase has been observed in a Mg-6Zn-3Al magnesium alloy, which may be the first discovery of a stable i-phase in this alloy. The dissolution of i-phase at grain boundaries leads to precipitation in the Mg-matrix during cooling. Nucleation characteristics, phase transformation, and interface morphology were investigated.
Article
Nanoscience & Nanotechnology
Yukiko Ogawa, Alok Singh, Hidetoshi Somekawa
Summary: The mechanical properties of a coarse-grained hexagonal close packed (hcp) single phase Mg-Sc alloy with two different textures, randomized or weakened, were investigated. Both textures exhibited a high elongation of over 30% and a moderately high ultimate tensile strength of about 240 MPa. Transmission electron microscopy (TEM) observations revealed the activation of both a- and c-component dislocations in the grain interiors, away from grain boundaries by over 20 μm. Thus, pyramidal slip can occur within the grain interiors of a coarse-grained Mg-Sc alloy.
SCRIPTA MATERIALIA
(2022)
Article
Chemistry, Physical
Elango Chandiran, Yukiko Ogawa, Rintaro Ueji, Hidetoshi Somekawa
Summary: The effect of grain size and strain rate on the room-temperature compression of pure magnesium was studied. It was found that the deformation mechanisms and grain-boundary sliding were significantly influenced by grain size and strain rate, and the Hall-Petch relationship broke down under certain conditions. Additionally, the deformation mode had a negligible impact on the dominant deformation mechanisms and the Hall-Petch breakdown.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Motohiro Yuasa, Ryoichi Sato, Takao Hoshino, Daisuke Ando, Yoshikazu Todaka, Hiroyuki Miyamoto, Hidetoshi Somekawa
Summary: Mg-9 at%Y-6 at%Zn and Mg-2 at%Y-1 at%Zn alloys were processed by equal-channel-angular extrusion (ECAE) to investigate their microstructure evolution and local hardness. The area fraction of the kink bands in the Mg-9 at%Y-6 at%Zn alloys increased with increasing the number of ECAE passes, resulting in higher hardness. In the Mg-2 at%Y-1 at%Zn alloys, the microstructural evolution of the alpha-Mg matrix phase and long-period stacking ordered (LPSO) phase by 1-pass ECAE and the increase in local hardness were discussed.
MATERIALS TRANSACTIONS
(2023)
Article
Materials Science, Multidisciplinary
Hidetoshi Somekawa, Yukiko Ogawa, Yoshinori Ono, Alok Singh
Summary: The effect of grain size and testing temperature on the mechanical properties and deformation behavior of extruded Mg-Al-Zn alloys was investigated. Smaller grain size and lower testing temperature led to increased strength, while the elongation-to-failure in tension was reduced at cryogenic-temperature. Grain refinement suppressed the formation of deformation twins and enhanced grain boundary plasticity. Interestingly, grain boundary compatibility promoted the activation of non-basal dislocation slips regardless of testing temperatures.
PHILOSOPHICAL MAGAZINE LETTERS
(2022)
Article
Nanoscience & Nanotechnology
Rintaro Ueji, Kenji Nagata, Hidetoshi Somekawa, Masahiko Demura
Summary: This study designed the chemical compositions and heat treatment conditions for low-alloyed TRIP steel using a sparse mixed regression method. Experimental results confirmed that these conditions provided high strength and large elongation. Evaluating the metallurgical parameters highlighted two different design concepts.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Physical
Hai Qiu, Rintaro Ueji, Tadanobu Inoue
Summary: Luders deformation is a type of discontinuous yielding in ferrite-pearlite steel, characterized by the yield-point phenomenon and localized plastic bands. The correlation between the yield-point phenomenon and the formation of plastic bands is unclear. In this study, the global and local deformation behaviors in the tension processes of four ferrite-pearlite steels were examined to investigate this correlation. The main findings are: (1) the degree of yield drop decreased with an increase in the pearlite fraction, and (2) a plastic band was formed at a certain stress level smaller than the upper yield stress; when the stress level was larger than 92% of the upper yield stress, the upper yield point disappeared.
Article
Chemistry, Physical
Hidetoshi Somekawa, Kimiyoshi Naito
Summary: The effect of micro-alloying with different elements on grain boundary sliding behavior at intermediate temperatures was examined. The micro-alloying element affects the damping capacity and the tensile response of the alloy. The partial contribution of grain boundary sliding to deformation is the major reason for the deviation of experimental results from calculated values.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Naomi Nishimura, Kazumasa Masaki, Wei Tan, Reona Iimura, Hiroaki Kobayashi, Kei Nishikawa, Toshihiko Mandai, Hidetoshi Somekawa, Yoichi Tominaga
Summary: To improve the cycle performance of Mg metal batteries, a polymer coating (PSTFSI-Mg) was applied on the surface of spinel-type MgMn2O4 cathode. The polymer coating promoted electron transfer between particles, as confirmed by transmission electron microscopy. Density functional theory calculations revealed that the polymer reduced the energy gap between the valence band maximum of MgMn2O4 and the highest occupied molecular orbital level of the electrolyte, thus suppressing electrolyte degradation.
JOURNAL OF PHYSICAL CHEMISTRY C
(2023)
Article
Chemistry, Physical
Hidetoshi Somekawa, Kei Nishikawa, Taku Moronaga, Takahito Ohmura
Summary: Two types of lithium metals with different average grain sizes were successfully produced through extrusion process and rapid molding process. The hardness of the metals was found to be influenced by grain size, decreasing with a finer grained structure, which is contrary to the trend observed in other light-weight pure metals. The fine-grained Li metal exhibited a large strain rate dependence and unusual behavior, attributed to the contribution of grain boundary sliding to deformation. Additionally, the fine-grained Li metal showed better electrochemical characteristics in terms of over-potential and voltage response during charging and discharging operations.
JOURNAL OF POWER SOURCES
(2023)
Article
Nanoscience & Nanotechnology
Hidetoshi Somekawa, Norie Motohashi, Shuji Kuroda, Toshihiko Mandai
Summary: Wide and thin Mg foils with thicknesses between 35 & mu;m and 400 & mu;m without any edge cracks are successfully produced. The initial microstructure in the billet is effective and essential for the processing. The mechanical properties of the foils are influenced by the foil thickness, as shown by hardness and tensile tests.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Elango Chandiran, Yukiko Ogawa, Rintaro Ueji, Alok Singh, Hidetoshi Somekawa
Summary: The effects of different crystallographic orientations of the grains on damping capacity (tan8) in magnesium alloys were investigated. The results showed that the grain orientation had a significant impact on the damping capacity of pure magnesium and Mg-Sc alloy. The absence of the solute atom Sc resulted in higher damping capacity in pure magnesium compared to the Mg-Sc alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Hidetoshi Somekawa, Motohiro Yuasa
Summary: The secondary formability and the effect of shape application on induced kink boundaries in Mg-9at.%Y-6at.%Zn alloy were investigated through experimental and numerical studies. A tube-shaped alloy without any cracks was successfully formed with kink boundaries associated with the applied shear strain. Numerical results showed a substantial shear strain at the contact region, but with an opposite shear direction after tube formation, indicating the possibility of de-kinking behavior. Additionally, the formed alloy exhibited higher hardness by 30 Hv compared to the un-processed alloy, and the correlation between kink density and hardness was consistent with literature results on wrought-processed Mg-Y-Zn alloys.
Article
Electrochemistry
Toshihiko Mandai, Hidetoshi Somekawa
Summary: The practical energy density of batteries incorporating elemental metals as anode active materials is largely influenced by the thickness of the metal anodes. However, the use of ultrathin magnesium foils is challenging due to the brittleness and unworkability of magnesium. This study successfully fabricated crack-free ultrathin magnesium foils with favorable microstructure by controlling the initial microstructure and rolling temperature, and demonstrated their excellent electrochemical characteristics as anode materials.
BATTERIES & SUPERCAPS
(2022)
Article
Materials Science, Multidisciplinary
Yukiko Ogawa, Alok Singh, Hidetoshi Somekawa
Summary: The damping capacities of three different phases (hcp, bcc, and martensite) in a Mg-Sc alloy were investigated. Results showed that the martensite phase exhibited a higher damping capacity compared to hcp and bcc phases. The higher damping capacity of the martensite phase is attributed to the movement of lattice defects, such as twin interfaces.
MRS COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Nizar Lefi, Salem Neily, Roland Bonnet
Summary: This paper investigates the elastic field in a bi-material crystal with an angular dislocation line with one branch placed in the crystal and the other along a strongly bound or welded interface. The analysis formulates the elastic field of a closed dislocation loop and solves it using the knowledge of the Green's tensor of the bi-material. The study provides a faster calculation method and has important implications for solving interfacial angular dislocation problems.
PHILOSOPHICAL MAGAZINE
(2024)
