Article
Materials Science, Multidisciplinary
Ning Su, Qingchen Deng, Yujuan Wu, Liming Peng, Kun Yang, Qiang Chen
Summary: This paper investigates the dissolution, refinement, and re-precipitation of LPSO structure/SFs in an Mg-Gd-Zn-Mn alloy through hot extrusion. The results suggest that refinement is dominated by the misalignment and re-dissolution mechanisms, with dislocation slips and rapid solute atom diffusion playing key roles. The evolution model of LPSO structure/SFs during continuous dynamic recrystallization is proposed based on the findings.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Qiang Yang, Shuhui Lv, Zixiang Yan, Xiru Hua, Xin Qiu, Jian Meng
Summary: This study reveals strong ductility asymmetry in extruded Mg alloys containing LPSO plates, which is mainly caused by deformation steps in LPSO plates, contributing significantly to compressive ductility. The results provide fundamental insights into deformation modes and mechanisms of thin LPSO plates, as well as a better understanding of the ductility asymmetry in extruded Mg alloys containing LPSO plates.
MATERIALS & DESIGN
(2021)
Article
Nanoscience & Nanotechnology
Kai Guan, Mariko Egami, Daisuke Egusa, Hajime Kimizuka, Michiaki Yamasaki, Yoshihito Kawamura, Eiji Abe
Summary: In this study, SRO solute clusters in the I-1 type LPSO phases in Mg-CoY alloys have been investigated using atomic-resolution STEM and first-principles calculations. The Co3Y5 SRO cluster model embedded across the I-1-type SFs has been successfully constructed to enhance the energetic stability of the LPSO phases. The findings reveal the crucial role of solute SRO clusters in the formation and stability of LPSO phases in ternary Mg alloys.
SCRIPTA MATERIALIA
(2022)
Article
Metallurgy & Metallurgical Engineering
Kai Guan, Daisuke Egusa, Eiji Abe
Summary: The microstructures of an as-cast Mg97.49Ho1.99Cu0.43Zr0.09 alloy were investigated using atomic resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The study revealed the presence of ordered long period stacking/order (LPSO) phases and short-range order (SRO) clusters embedded in stacking fault layers. The results support the importance of L1(2)-type TM6RE8 clusters in the formation of LPSO phases.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Nanoscience & Nanotechnology
Kaixuan Li, Yuanlin Zhuang, Ligong Zhao, Dongshan Zhao, He Zheng, Shuangfeng Jia, Ying Zhang, Peili Zhao, Jianian Gui, Jianbo Wang
Summary: The study investigated the interaction between deformation twinning and long period stacking ordered (LPSO) structures in an Mg-based alloy, showing the hindrance of LPSO structures and stacking faults to twinning. The in-situ experiments revealed that thick LPSO plates effectively retard the twinning propagation, and the closer spacing between LPSO structures further suppresses twin propagation. Additionally, the study discussed the resistance of stacking faults to twinning at the atomic scale, and the strengthening effect of LPSO structures on suppressing twinning growth.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Krishna Yaddanapudi, Brandon Leu, M. Arul Kumar, Xin Wang, Julie M. Schoenung, Enrique J. Lavernia, Timothy J. Rupert, Irene J. Beyerlein, Subhash Mahajan
Summary: This study investigated {(1) over bar 012} tensile twins terminating inside the grains of a deformed Mg-Y alloy using transmission electron microscopy. Crystallographic features of the terminating twins and associated slip structures were quantified and analyzed, with local stresses computed using crystal plasticity simulations. Basal < a > and < c + a > matrix glide were found to accommodate the plastic stresses near the terminating twins, with defect contrast consistent with lattice dislocations and twinning partials observed along the twin boundary. A dislocation reaction was proposed to establish the interrelationship between matrix glide and {(1) over bar 012} twinning in Mg-Y alloys.
Article
Nanoscience & Nanotechnology
Cyril Cayron
Summary: Recent studies have reported a hexagonal phase in high carbon steels, but it has been shown that this structure is actually the result of double diffraction and streaking effects caused by twins and stacking faults, rather than a superstructure. Similar misunderstandings have also been found in papers reporting exotic structures in aluminum, copper, and diamonds.
SCRIPTA MATERIALIA
(2021)
Article
Metallurgy & Metallurgical Engineering
Fanzhi Meng, Shuhui Lv, Qiang Yang, Xin Qiu, Zixiang Yan, Qian Duan, Jian Meng
Summary: This study investigated the components and crystal structures of intermetallic phases in a gravity die-cast Mg-6.0Zn-1.5Nd-0.5Zr alloy using transmission electron microscopy. The results revealed multiple intermetallic phases and various internal faults in the alloy. The study also revealed new orientation relationships between different intermetallic phases.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Chemistry, Physical
Hsin-Li Liang, Che-Wei Tsai, Sheng Guo
Summary: This study successfully designed corrosion-resistant CoCrFeMoNi HEAs with single-phase structure using two strategies, and validated the effectiveness of these methods through thermal stability. The corrosion resistance of these HEAs was found to be competitive compared to Hastelloy C276.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
M. L. Jenkins, G. D. W. Smith
Summary: Researchers attempted to discredit the identification of the 9R structure of copper precipitates in iron, but were unable to provide convincing evidence. High-resolution micrographs and other observations supported the robust identification of the 9R structure, highlighting flaws in the opposing interpretation.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
M. R. Gazizov, A. O. Boev, C. D. Marioara, R. Holmestad, M. Yu Gazizova, R. O. Kaibyshev
Summary: The study analyzed the coherent edge interface structures of thin {111}(Al) Omega plates in a peak-aged Al-Cu-Mg-Ag alloy using atomic-resolution STEM, finding that these edge interfaces can tilt from their orthogonal orientations to the broad plate surfaces. The edge interface tilts are correlated with shear component orientations along the broad plate surfaces and vary with plate thicknesses, while Cu atoms tend to occupy specific atomic sites near the edge interfaces in the Al matrix region.
MATERIALS CHARACTERIZATION
(2022)
Article
Nanoscience & Nanotechnology
Cheng Liu, Xiaohua Yang, Jianchao Peng, Bin Liu, Qun Luo, Qian Li, Kuo-Chih Chou
Summary: The deformation behaviors of a dual-phase Mg alloy containing α-Mg and 18R-LPSO phases were investigated in this study. The 18R phase, accounting for 11.3 vol.%, contributed to 23.0% of the overall alloy deformation. The coordinated twinning deformation of α-Mg matrix through the slip of basal dislocations and the kinking deformation of Mg slices induced by the 18R phase were observed during the early stage of deformation. At the end of deformation, a large number of T2-type stacking faults were generated, improving the ductility of the alloy. This work provides a novel strategy for designing high-strength and good ductility dual-phase Mg alloys.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Yunhe Zheng, Laure Bourgeois, Jian-Feng Nie
Summary: This study investigated the structure of precipitates in Mg-Zn-Al alloys, revealing new structural features and proposing that the rod-shaped precipitates can be described by tiling of different shapes.
SCRIPTA MATERIALIA
(2021)
Article
Engineering, Biomedical
Diana C. Martinez, Anna Dobkowska, Romy Marek, Hanna Cwieka, Jakub Jaroszewicz, Tomasz P. Plocinski, Crtomir Donik, Heike Helmholz, Berengere Luthringer-Feyerabend, Berit Zeller-Plumhoff, Regine Willumeit-Roemer, Wojciech Swieszkowski
Summary: This study investigated the degradation of an Mg-0.45Zn-0.45Ca (ZX00) screw in vitro and in vivo. The results showed that the ZX00 alloy promoted bone healing and the formation of new bone. Despite the correlation with the production procedure, the ZX00 alloy was still suitable for temporary bone implants.
BIOACTIVE MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Zhiwen Zheng, Cong Peng, Qingan Zhang
Summary: In this work, the hydrogen storage properties of the Mg85Zn6Y9 alloy with 94 wt.% of 18R-type LPSO phase were investigated. The 18R phase easily decomposes into various phases during ball milling under a hydrogen atmosphere. The Mg85Zn6Y9 alloy exhibits better hydrogen storage kinetics and cycle durability compared to pure Mg due to the catalytic effect of YH2/YH3 and the inhibition role of the Laves phase.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
M. Egami, I. Ohnuma, M. Enoki, H. Ohtani, E. Abe
MATERIALS TRANSACTIONS
(2020)
Article
Materials Science, Multidisciplinary
Mitsuhiro Itakura, Masatake Yamaguchi, Daisuke Egusa, Eiji Abe
Summary: Solute clusters in long period stacking order (LPSO) alloys play a crucial role in their unique plastic behavior, but there is uncertainty regarding the presence of interstitial atoms in these clusters. Using density functional theory calculations, it was found that solute clusters in Mg-Y-Zn LPSO alloy should include interstitial atoms, primarily Mg. This finding simplifies the atomistic modeling of solute clusters in these alloys and suggests that increased vacancy density accelerates cluster growth through the emission of vacancies from the cluster.
Article
Materials Science, Multidisciplinary
Toshihiro Hara, Daisuke Egusa, Mami Mihara, Hiroki Tanaka, Ikuo Ohnuma, Eiji Abe
Summary: The study found that the softening phenomenon in the Al-Fe alloy is attributed to the highly purified aluminum matrix, leading to the occurrence of dynamic recovery and/or recrystallization in deformation ranges.
MATERIALS TRANSACTIONS
(2021)
Article
Materials Science, Multidisciplinary
Daisuke Egusa, Koji Inoue, Yasuyoshi Nagai, Eiji Abe
Summary: The study found that kink boundaries (KBs) undergo reconstruction during post-annealing, forming local hexagonal close-packed Mg regions and enhancing thermal stability. The reconstruction of dislocation structures plays an important role in solute-enriched face-centered cubic layers within LPSO structures.
MATERIALS CHARACTERIZATION
(2021)
Article
Polymer Science
Tatsuhiko Murayama, Eiji Abe, Hiromu Saito
Summary: Through heat elongation treatment, the mechanical properties of extruded high-density polyethylene film were improved, including increased tensile strength and disappearance of the yield point. Experimental results showed that elongation led to a more regular lamellar structure, increased chain orientation, and suppression of lamellar fracture and void formation.
Article
Nanoscience & Nanotechnology
Kai Guan, Mariko Egami, Daisuke Egusa, Hajime Kimizuka, Michiaki Yamasaki, Yoshihito Kawamura, Eiji Abe
Summary: In this study, SRO solute clusters in the I-1 type LPSO phases in Mg-CoY alloys have been investigated using atomic-resolution STEM and first-principles calculations. The Co3Y5 SRO cluster model embedded across the I-1-type SFs has been successfully constructed to enhance the energetic stability of the LPSO phases. The findings reveal the crucial role of solute SRO clusters in the formation and stability of LPSO phases in ternary Mg alloys.
SCRIPTA MATERIALIA
(2022)
Article
Metallurgy & Metallurgical Engineering
Kai Guan, Daisuke Egusa, Eiji Abe
Summary: The microstructures of an as-cast Mg97.49Ho1.99Cu0.43Zr0.09 alloy were investigated using atomic resolution high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM). The study revealed the presence of ordered long period stacking/order (LPSO) phases and short-range order (SRO) clusters embedded in stacking fault layers. The results support the importance of L1(2)-type TM6RE8 clusters in the formation of LPSO phases.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Metallurgy & Metallurgical Engineering
Kai Guan, Daisuke Egusa, Eiji Abe, Jinghuai Zhang, Xin Qiu, Qiang Yang, Jian Meng
Summary: The effect of Gd content on the microstructure and tensile properties of as-cast Mg-Sm-Zn-Zr alloy was investigated. The addition of Gd inhibited the segregation behavior of Zn in the Mg3Sm phase and improved the tensile yield stress of the alloy. Gd-modified alloys exhibited significant age-hardening effect, attributed to the high-volume fraction and high density nano-scale precipitates.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Materials Science, Multidisciplinary
Daisuke Egusa, Ryo Manabe, Takuro Kawasaki, Stefanus Harjo, Shigeo Sato, Eiji Abe
Summary: Based on X-ray diffraction analysis, this study attempts to quantify the volume fraction of solute-enriched stacking faults (SESFs) in Mg-Zn-Gd alloys with a hexagonal-close-packed structure. It is found that SESFs with a local face-center-cubic stacking mainly exist with a limited thickness, causing anisotropic broadening of the diffraction peaks, including the c*-component. By treating SESFs as intergrowth-like precipitates, the asymmetric peak profile can be successfully decomposed into the hcp-matrix and SESF peaks, allowing for a highly quantitative estimation of the relevant volume fractions.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Kakeru Ninomiya, Koki Itamoto, Hiroyuki Setoyama, Daisuke Egusa, Eiji Abe, Michiaki Yamasaki, Maiko Nishibori
Summary: This study investigated the formation of L12 clusters and the interactions between transition metal (TM) and rare-earth (RE) atoms in magnesium-based alloys. X-ray absorption spectroscopy (XAS) and ab initio calculations were used to analyze the alloy before and after aging. The results showed that rare-earth elements play a crucial role in the formation of L12 clusters.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Koji Kimura, Daisuke Egusa, Koji Hagihara, Nohisa Happo, Naomi Kawamura, Hiroo Tajiri, Kouichi Hayashi, Eiji Abe
Summary: X-ray fluorescence holography was used to study the dilute Mg99.2Zn0.2Y0.6 alloy annealed at 520 celcius for 5 h and obtain atomic images around Zn atom. Clear hologram patterns were obtained despite the low concentration of solute-element. The reconstructed atomic images revealed that Zn atoms mainly occupy the hcp Mg site in this annealed alloy, consistent with the transmission electron microscope image.
MATERIALS TRANSACTIONS
(2023)
Article
Materials Science, Multidisciplinary
Y. Liu, K. Zweiacker, C. Liu, J. T. McKeown, J. M. K. Wiezorek
Summary: The evolution of rapid solidification microstructure and solidification interface velocity of hypereutectic Al-20at.%Cu alloy after laser melting has been studied experimentally. It was found that the formation of microstructure was dominated by eutectic, alpha-cell, and banded morphology grains, and the growth modes changed with increasing interface velocity.
Article
Materials Science, Multidisciplinary
Bharat Gwalani, Julian Escobar, Miao Song, Jonova Thomas, Joshua Silverstein, Andrew Chihpin Chuang, Dileep Singh, Michael P. Brady, Yukinori Yamamoto, Thomas R. Watkins, Arun Devaraj
Summary: Castable alumina forming austenitic alloys exhibit superior creep life and oxidation resistance at high temperatures. This study reveals the mechanism behind the enhanced creep performance of these alloys by suppressing primary carbide formation and offers a promising alloy design strategy for high-temperature applications.
Article
Materials Science, Multidisciplinary
Jian Song, Qi Zhang, Songsong Yao, Kunming Yang, Houyu Ma, Jiamiao Ni, Boan Zhong, Yue Liu, Jian Wang, Tongxiang Fan
Summary: Recent studies have shown that achieving an atomically flat surface for metals can greatly improve their oxidation resistance and enhance their electronic-optical applications. Researchers have explored the use of graphene as a covering layer to achieve atomically flat surfaces. They found that high-temperature deposited graphene on copper surfaces formed mono-atomic steps, while annealed copper and transferred graphene on copper interfaces formed multi-atomic steps.
Article
Materials Science, Multidisciplinary
Jennifer A. Glerum, Jon-Erik Mogonye, David C. Dunand
Summary: Elemental powders of Al, Ti, Sc, and Zr are blended and processed via laser powder-bed fusion to create binary and ternary alloys. The microstructural analysis and mechanical testing show that the addition of Ti results in the formation of primary precipitates, while the addition of Sc and Zr leads to the formation of fine grain bands. The Al-0.25Ti-0.25Zr alloy exhibits comparable strain rates to Al-0.5Zr at low stresses, but significantly higher strain rates at higher stresses during compressive creep testing. Finite element modeling suggests that the connectivity of coarse and fine grain regions is a critical factor affecting the creep resistance of the alloys.
Article
Materials Science, Multidisciplinary
P. Jannotti, B. C. Hornbuckle, J. T. Lloyd, N. Lorenzo, M. Aniska, T. L. Luckenbaugh, A. J. Roberts, A. Giri, K. A. Darling
Summary: This work characterizes the thermo-mechanical behavior of bulk nanocrystalline Cu-Ta alloys under extreme conditions. The experiments reveal that the alloys exhibit unique mechanical properties, behaving differently from conventional nanocrystalline Cu. They do not undergo grain coarsening during extrusion and exhibit behavior similar to coarse-grained Cu.
Article
Materials Science, Multidisciplinary
Yiqing Wei, Jingwei Li, Daliang Zhang, Bin Zhang, Zizhen Zhou, Guang Han, Guoyu Wang, Carmelo Prestipino, Pierric Lemoine, Emmanuel Guilmeau, Xu Lu, Xiaoyuan Zhou
Summary: This study proposes a new strategy to modify microstructure by phase regulation, which can simultaneously enhance carrier mobility and reduce lattice thermal conductivity. The addition of Cu in layered SnSe2 induces a phase transition that leads to increased grain size and reduced stacking fault density, resulting in improved carrier mobility and lower lattice thermal conductivity.
Article
Materials Science, Multidisciplinary
Jia Chen, Zhengyu Zhang, Eitan Hershkovitz, Jonathan Poplawsky, Raja Shekar Bhupal Dandu, Chang-Yu Hung, Wenbo Wang, Yi Yao, Lin Li, Hongliang Xin, Honggyu Kim, Wenjun Cai
Summary: In this study, the structural origin of the pH-dependent repassivation mechanisms in multi-principal element alloys (MPEA) was investigated using surface characterization and computational simulations. It was found that selective oxidation in acidic to neutral solutions leads to enhanced nickel enrichment on the surface, resulting in reduced repassivation capability and corrosion resistance.
Article
Materials Science, Multidisciplinary
X. Y. Xu, C. P. Huang, H. Y. Wang, Y. Z. Li, M. X. Huang
Summary: The limited slip systems of magnesium (Mg) and its alloys hinder their wide applications. By conducting tensile straining experiments, researchers discovered a rate-dependent transition in the dislocation mechanisms of Mg alloys. At high strain rates, glissile dislocations dominate, while easy-glide dislocations dominate at low strain rates. Abundant glissile dislocations do not necessarily improve ductility.
Article
Materials Science, Multidisciplinary
M. S. Szczerba, M. J. Szczerba
Summary: Inverse temperature dependences of the detwinning stress were observed in face-centered cubic deformation twins in Cu-8at.%Al alloy. The detwinning stress increased with temperature when the pi detwinning mode was involved, but decreased when the pi/3 mode was involved. The dual effect of temperature on the detwinning stress was due to the reduction of internal stresses pre-existing within the deformation twins. The complete reduction of internal stresses at about 530 degrees C led to the equivalence of the critical stresses of different detwinning modes and a decrease in the yield stress anisotropy of the twin/matrix structure.
Article
Materials Science, Multidisciplinary
Taowen Dong, Tingting Qin, Wei Zhang, Yaowen Zhang, Zhuoran Feng, Yuxiang Gao, Zhongyu Pan, Zixiang Xia, Yan Wang, Chunming Yang, Peng Wang, Weitao Zheng
Summary: The interaction between the electrode and the electric double layer (EDL) significantly influences the energy storage mechanism. By studying the popular alpha-Fe2O3 electrode and the EDL interaction, we find that the energy storage mechanism of the electrode can be controlled by modulating the EDL.
Article
Materials Science, Multidisciplinary
Matthew R. Barnett, Jun Wang, Sitarama R. Kada, Alban de Vaucorbeil, Andrew Stevenson, Marc Fivel, Peter A. Lynch
Summary: The elastic-plastic transition in magnesium alloy Mg-4.5Zn exhibits bursts of deformation, which are characterized by sudden changes in grain orientation. These bursts occur in a coordinated manner among nearby grains, with the highest burst rate observed at the onset of full plasticity. The most significant burst events are associated with twinning, supported by the observation of twinned structures using electron microscopy. The bursts are often preceded and followed by a stasis in peak movement, indicating a certain "birth size" for twins upon formation and subsequent growth at a later stage.
Article
Materials Science, Multidisciplinary
Vaidehi Menon, Sambit Das, Vikram Gavini, Liang Qi
Summary: Understanding solute segregation thermodynamics is crucial for investigating grain boundary properties. The spectral approach and thermodynamic integration methods can be used to predict solute segregation behavior at grain boundaries and compare with experimental observations, thus aiding in alloy design and performance control.
Article
Materials Science, Multidisciplinary
Feiyu Qin, Lei Hu, Yingcai Zhu, Yuki Sakai, Shogo Kawaguchi, Akihiko Machida, Tetsu Watanuki, Yue-Wen Fang, Jun Sun, Xiangdong Ding, Masaki Azuma
Summary: This study reports on the negative and zero thermal expansion properties of Cd2Re2O7 and Cd1.95Ni0.05Re2O7 materials, along with their ultra-low thermal conductivity. Through investigations of their structures and phonon calculations, the synergistic effect of local structure distortion and soft phonons is revealed as the key to achieving these distinctive properties.
Article
Materials Science, Multidisciplinary
Thomas Beerli, Christian C. Roth, Dirk Mohr
Summary: A novel testing system for miniature specimens is designed to characterize the plastic response of materials for which conventional full-size specimens cannot be extracted. The system has an automated operation process, which reduces the damage to specimens caused by manual handling and improves the stability of the test results. The experiments show that the miniature specimens extracted from stainless steel and aluminum have high reproducibility, and the results are consistent with those of conventional-sized specimens. A correction procedure is provided to consider the influence of surface roughness and heat-affected zone caused by wire EDM.
Article
Materials Science, Multidisciplinary
Rani Mary Joy, Paulius Pobedinskas, Nina Baule, Shengyuan Bai, Daen Jannis, Nicolas Gauquelin, Marie-Amandine Pinault-Thaury, Francois Jomard, Kamatchi Jothiramalingam Sankaran, Rozita Rouzbahani, Fernando Lloret, Derese Desta, Jan D'Haen, Johan Verbeeck, Michael Frank Becker, Ken Haenen
Summary: This study investigates the influence of film microstructure and composition on the Young's modulus and residual stress in nanocrystalline diamond thin films. The results provide insights into the mechanical properties and intrinsic stress sources of these films, and demonstrate the potential for producing high-quality nanocrystalline diamond films under certain conditions.