Article
Chemistry, Physical
Masaki Tahara, Kazuya Hasunuma, Hideki Hosoda
Summary: This study investigated the decomposition process of the isothermal alpha '' phase in beta-Ti alloys, and found that the resulting alpha + beta dual phase inherited the microstructural characteristics of the alpha ''(iso) phase. The research results indicate the existence of a strict variant selection rule between the decomposed alpha and beta phases, with a specific variant combination observed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Nanoscience & Nanotechnology
Ivan S. Pavlov, Anna G. Ivanova, Vladimir P. Filonenko, Igor P. Zibrov, Alexei E. Voloshin, Pavel V. Zinin, Alexander L. Vasiliev
Summary: This study investigates the formation of boron carbide superhard particles through a liquid-phase reaction at high pressure and high temperature. The synthesized particles exhibit a rhombic hexecontahedron morphology with twelve five-vertex stars. Electron microscopy and X-ray diffraction were used to analyze the crystal structure of these particles, revealing multiple cycling twinning rather than quasi-crystalline symptoms. The specific shape of the particles is explained by the decrease of surface energy during formation at high pressure and high temperature.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Xiaofen Tan, Matthew Weyland, Yu Chen, Timothy Williams, Philip N. H. Nakashima, Laure Bourgeois
Summary: This study investigates voids coated with a monolayer of tin in aluminum alloys, finding that tubular voids can grow to hundreds of nanometers in length under certain heat treatment conditions with high coherence with the Al matrix. The aspect ratios of tubular voids show a strong correlation with the coherence between the tin particle and the arrangement of the tin atoms in the void coating, suggesting potential for future research and applications.
Article
Chemistry, Physical
Gabriel R. Reisinger, Klaus W. Richter
Summary: Different synthesis approaches and conditions for misfit layer compounds (MLCs) in the ternary systems V-Se-Bi, V-Se-Pb, and V-Se-Sn were compared. The best results were achieved with NH4Cl as a crystallisation aid, moderate annealing temperatures, and longer annealing durations. The study discussed the compositions, morphology, and structure, and found that either plate-like or tubelike MLC crystals could be obtained depending on the stacking sequence of the compounds. The structural properties of MLC (PbSe)1+delta VSe2 were comparable to the corresponding ferecrystals in the literature.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Microscopy
Steven E. Zeltmann, Shang-Lin Hsu, Hamish G. Brown, Sandhya Susarla, Ramamoorthy Ramesh, Andrew M. Minor, Colin Ophus
Summary: Nanobeam electron diffraction is used to probe the local structural properties of complex crystalline materials. A stacked Bloch wave method is developed to model the diffracted intensities from thick samples with varying structure. The method is successfully applied to extract material properties and elucidate complex vortex topologies in multilayer samples.
Article
Chemistry, Physical
Xin Fu Tan, Sergey A. Belyakov, Te-Cheng Su, Qinfen Gu, Shiqian Liu, Stuart D. McDonald, Christopher M. Gourlay, Hideyuki Yasuda, Syo Matsumura, Kazuhiro Nogita
Summary: The addition of 6 wt% Ni to the Cu current collector greatly accelerates the growth of (Cu,Ni)(6)Sn-5 in Cu-xNi/Sn solid-melt couples, leading to a growth rate of up to 50x faster and reducing the processing time above 200 degrees C to less than 10 min.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Jiwon Jeong, Woo-Sung Jang, Kwang Hun Kim, Aleksander Kostka, Gilho Gu, Young-Min Kim, Sang Ho Oh
Summary: This study evaluates two advanced, automated crystal orientation mapping techniques suitable for nanocrystalline materials. The comparison shows that TEM-PED is more reliable for characterizing grains oriented along low-index zone axes, while SEM-TKD is better at detecting small misorientation between grains, providing better quantification and statistical analysis of grain orientation. Both techniques are complementary tools for nanocrystalline materials and can be selected based on analysis requirements, as they have competitive performance in terms of angular resolution and texture quantification.
MICROSCOPY AND MICROANALYSIS
(2021)
Article
Materials Science, Multidisciplinary
Alexandra Bruefach, Colin Ophus, Mary C. Scott
Summary: Understanding material structure is crucial for enhancing device performance. This article introduces an unsupervised clustering pipeline for engineering 4D-STEM feature representations, which is applied to both simulated and experimental data. The results demonstrate the reliable identification of overlapping grains using this method.
MICROSCOPY AND MICROANALYSIS
(2022)
Article
Materials Science, Multidisciplinary
Yung Suk Jeremy Yoo, Anastasia Mullins, Sazol Has, DaeHoon Kang, Richard Hamerton, Saransh Singh, Marc De Graef, Josh Kacher
Summary: The influence of dispersoids and grain boundary characteristics on the crack propagation behavior in AA3xxx during deep drawing was investigated, with cracks typically forming on the material surface at the earliest stages of deformation and extending with increasing strain. The cracks propagated along intergranular paths with bifurcations correlating with triple junction locations, but no strong trends were identified linking grain boundary characteristics to crack propagation pathways. Dispersoids at grain boundaries were found to arrest crack propagation and divert crack growth pathways, demonstrating the first practical application of combining the dictionary indexing method with TKD analysis.
JOURNAL OF MATERIALS RESEARCH
(2021)
Article
Polymer Science
Botao Hao, Zhiyuan Ding, Xudong Tao, Peter D. Nellist, Hazel E. Assender
Summary: Polyvinyl alcohol (PVA) is a promising material in medical and packaging applications due to its biocompatibility, water solubility, low density, and cost-effectiveness. This study uses electron ptychography to image the crystallinity of PVA, revealing deviations from previous models derived from X-ray diffraction. A new model is proposed based on these findings, and simulated results confirm its accuracy. The ability to directly image molecular order in PVA crystals opens up new opportunities for research in this field.
Article
Materials Science, Multidisciplinary
Tian-Xing Yang, Zhan-Xing Li, Chang-Jun Zhou, Yi-Chun Xu, Peng Dou
Summary: FeCrAl oxide dispersion strengthened (ODS) steel is a promising cladding material for Generation IV nuclear reactors due to its superior properties. The morphologies, crystal structures, and metal/oxide interface structures of two FeCrAl ODS steels were studied. The dispersion morphology of oxides in the 3.7Al-0.1Ti-0.6Zr ODS steel was found to be better than that of the 3.3Al-0.5Zr ODS steel. The proportions of different oxides in the two ODS steels were characterized. The mechanisms of oxide formation, polymorphic transition, and strengthening in the ODS steels were discussed.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Cell Biology
Kiranjit K. Bains, Robert D. Young, Elena Koudouna, Philip N. Lewis, Andrew J. Quantock
Summary: Imaging techniques were used to study the three-dimensional microanatomy and spatiotemporal relationships of cells, extracellular matrix, and vasculature at the corneo-scleral limbus of developing and mature chicken eyes. Results showed the development of structures similar to Palisades of Vogt, associated with characteristics of stem cells, and direct cell-cell associations between corneal epithelial and stromal cells.
Article
Nanoscience & Nanotechnology
T. W. J. Kwok, T. P. McAuliffe, A. K. Ackerman, B. H. Savitzky, M. Danaie, C. Ophus, D. Dye
Summary: A TWIP steel with a specific composition was deformed to 6% strain and analyzed using 4D-STEM technique. It was found that the average elastic strain parallel and perpendicular to the twinning direction was about 6%, but there were hot spots with even larger strains up to 12%. These hot spots were attributed to a high density of Frank dislocations on the twin boundary. The strain fields in the TWIP steel were significantly larger than other twinning materials, and could explain the early thickness saturation of nanotwins.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Xuhao Hong, Steven E. Zeltmann, Benjamin H. Savitzky, Luis Rangel DaCosta, Alexander Muller, Andrew M. Minor, Karen C. Bustillo, Colin Ophus
Summary: Transmission electron microscopy (TEM) is used to measure diffraction pattern images for crystal structure and orientation determination. Nanobeam electron diffraction (NBED) is suitable for polycrystalline samples. The multibeam electron diffraction (MBED) technique is effective for crystalline orientation mapping and 3D tomographic reconstruction.
MICROSCOPY AND MICROANALYSIS
(2021)
Article
Chemistry, Physical
Munmun Basak, Md Lutfor Rahman, Md Farid Ahmed, Bristy Biswas, Nahid Sharmin
Summary: Cobalt ferrite nanoparticles were synthesized using co-precipitation technique with different precipitating agents, affecting the structure and size distribution. Various analysis methods showed highly correlated results, with SSP method being the most compatible.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Daixiu Wei, Liqiang Wang, Yongjie Zhang, Wu Gong, Tomohito Tsuru, Ivan Lobzenko, Jing Jiang, Stefanus Harjo, Takuro Kawasaki, Jae Wung Bae, Wenjun Lu, Zhen Lu, Yuichiro Hayasaka, Takanori Kiguchi, Norihiko L. Okamoto, Tetsu Ichitsubo, Hyoung Seop Kim, Tadashi Furuhara, Evan Ma, Hidemi Kato
Summary: Recently-developed high-entropy alloys (HEAs) have expanded the compositional space and mechanical properties by substituting the constituent metals with metalloids. Metalloid substitution increases strength by increasing local lattice distortion and short-range chemical inhomogeneities, while reducing stacking fault energy to discourage dynamic recovery.
Article
Chemistry, Physical
Yu-Lien Wu, Chih-Yang Huang, Hung-Yang Lo, Fang-Chun Shen, An-Yuan Ho, Yi-Tang Tseng, Akira Yasuhara, Wen-Wei Wu
Summary: Cu-Zn based alloys are widely used for their excellent properties, such as high electrical conductivity and increased hardness over pure Cu. This study investigates the atomic-scale microstructural evolution of Cu-Zn systems, revealing the formation of alpha phase and nanotwins to optimize mechanical properties. The research provides novel insights into Cu-Zn alloys for potential applications in various alloy systems.
APPLIED SURFACE SCIENCE
(2022)
Article
Chemistry, Physical
Akira Yasuhara, Takumi Sannomiya
Summary: Metallic nanoparticles, especially those alloyed with multiple metal elements, have been widely studied for their unique electrical, optical, and catalytic properties. Interfaces between different phases and grain boundaries play a significant role in determining the catalytic efficiency and chemical stability of the alloy nanoparticles. In this study, Au-Ag-Cu ternary alloy nanoparticles were synthesized and their atomically localized structures, particularly at the grain boundaries, were investigated. The findings provide insights into the interface structure of these nanoparticles.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Inorganic & Nuclear
Takuya Hatakeyama, Norihiko L. Okamoto, Tetsu Ichitsubo
Summary: This study investigates the thermal stability of alpha, beta, gamma, delta, and lambda-type MnO2 polymorphs using DSC and HTXRD. Results show that the thermal stability order of the polymorphs is beta > alpha > gamma > delta approximate to lambda. The structure and phase transformations of each phase under high temperature conditions are discussed in relation to the bonding environment of oxide ions.
JOURNAL OF SOLID STATE CHEMISTRY
(2022)
Article
Nanoscience & Nanotechnology
Han Zhang, Yu Jimbo, Akira Niwata, Akihiro Ikeda, Akira Yasuhara, Cretu Ovidiu, Koji Kimoto, Takeshi Kasaya, Hideki T. Miyazaki, Naohito Tsujii, Hongxin Wang, Yasushi Yamauchi, Daisuke Fujita, Shin-ichi Kitamura, Hironobu Manabe
Summary: The study developed a LaB6 nanowire-based electron source that emitted a highly collimated electron beam with good lateral and angular alignment. The electron source demonstrated excellent performance in achieving atomic resolution in both broad-beam and probe-forming modes.
NATURE NANOTECHNOLOGY
(2022)
Article
Geochemistry & Geophysics
Jangmi Han, Ichiro Ohnishi, Akira Yasuhara, Lindsay P. Keller
Summary: Hibonite is a refractory mineral commonly found in primitive meteorites, and planar defects have been observed in it using transmission electron microscopy. These defects may be related to magnesium substitution, and they indicate non-equilibrium crystal growth during the high-temperature formation of hibonite.
AMERICAN MINERALOGIST
(2022)
Article
Multidisciplinary Sciences
Takuya Hatakeyama, Norihiko L. Okamoto, Satoshi Otake, Hiroaki Sato, Hongyi Li, Tetsu Ichitsubo
Summary: This study demonstrates that birnessite-type layered manganese dioxide with crystal water can serve as a well-balanced heat storage material due to its water-intercalation mechanism, high energy density, and validated driving force for intercalation, providing an optimal solution for low-grade waste-heat applications.
NATURE COMMUNICATIONS
(2022)
Article
Nanoscience & Nanotechnology
Xiatong Ye, Hongyi Li, Takuya Hatakeyama, Hiroaki Kobayashi, Toshihiko Mandai, Norihiko L. Okamoto, Tetsu Ichitsubo
Summary: Rechargeable magnesium batteries are promising candidates for future batteries due to their abundant resources and high energy density. This study compares the reaction behavior of different MnO2 cathodes in two electrolytes and highlights the importance of interfacial stability for practical applications.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Robert Josef Enzinger, Martin Luckabauer, Norihiko L. Okamoto, Tetsu Ichitsubo, Wolfgang Sprengel, Roland Wurschum
Summary: A detailed understanding of the kinetics of phase formation in fi-stabilised titanium is crucial for their applicability, but specialized measurement techniques are needed due to the complex nature and long timescales of the transformations. High-stability isothermal laser dilatometry was used to study the volume changes of Ti-21 at. pct V samples during phase formation. Different behaviors were observed between samples with different solute oxygen content, and the temperature ranges for diffusionless and diffusion-assisted isothermal w-formation as well as w-to-a transformation were determined. The results confirm recent findings on the distinction between diffusionless and diffusion-assisted isothermal w formation modes. Modelling of w-phase formation using Austin-Rickett kinetics revealed temperature-dependent formation rates, which were used to develop isothermal TTT-diagrams reflecting the strong influence of oxygen content.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
Kaoru Okamoto Yoshiyama, Norihiko L. Okamoto, Jun Hidema, Atsushi Higashitani
Summary: Far-ultraviolet radiation C light (far-UVC; 222 nm wavelength) has been considered as a safer light for killing pathogenic bacteria and viruses, but its effectiveness and potential biological damage compared to 254-UVC (254 nm wavelength) were unclear. This study found that 222-UVC caused slightly less DNA damage but had a significant effect on motility loss and severe damage to the sensory nervous system in a model organism, Caenorhabditis elegans. In contrast, 254-UVC had a higher impact on survival of eggs and chromosomal condensation. These results suggest that 222-UVC is less penetrating but causes more severe damage in tissues near the surface.
Article
Chemistry, Multidisciplinary
Toru Ishikawa, Fumihiko Tanaka, Kosuke Kurushima, Akira Yasuhara, Ryusuke Sagawa, Tatsuya Fujita, Ryohei Yonesaki, Katsuhiko Iseki, Takayuki Nakamuro, Koji Harano, Eiichi Nakamura
Summary: Carbon fiber obtained by pyrolysis of polyacrylonitrile exhibits superior properties for various applications, such as aircraft manufacture and power turbine blades. The structure of polyacrylonitrile-derived carbon fiber consists of hierarchically piled up wavy graphene-like networks, which exhibit high tensile strength and resistance to fracture. Conversely, pitch-based carbon fiber, consisting of crystalline graphene networks, is brittle.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Nanoscience & Nanotechnology
Jia-Wei Chen, Yun-Guan Wei, Hung-Yang Lo, Sicheng Lu, Yi-Che Chen, Chi-Fong Lei, Po-Liang Liu, Pu Yu, Nien-Ti Tsou, Akira Yasuhara, Wen-Wei Wu, Ying-Hao Chu
Summary: Quasi van der Waals epitaxy is a method to construct combinations of 2D and 3D materials. The interface structure and mechanical robustness of metal/muscovite systems have been studied. The anisotropic thermal expansion and thermal stress tolerance in the silver/muscovite heteroepitaxy have been discovered and demonstrated. The electrothermal and photothermal methods show fast response to thermal stress, proving the interface robustness.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Chemistry, Inorganic & Nuclear
Kunio Yubuta, Akira Yasuhara, Akiko Nomura, Toetsu Shishido, Kazumasa Sugiyama, Kaoru Kouzu, Shigeru Okada, Takao Mori
Summary: Self-flux grown alpha-HoAlB4 and alpha-ErAlB4 single crystals exhibit spin glass magnetic behavior. Spherical aberration-corrected scanning transmission electron microscopy techniques reveal substitutions in the Al atom sites, which play a significant role in stabilizing the YCrB4-type compounds.
SOLID STATE SCIENCES
(2023)
Article
Chemistry, Physical
Norihiko L. Okamoto, Hiroki Yoshisako, Tetsu Ichitsubo
Summary: Layered manganese dioxide with K cations and water molecules shows reversible heat storage properties, but the initial irreversible capacity of water intercalation limits the energy density for subsequent cycles. This study analyzes the crystal structures of K-containing birnessite before and after heat treatment to understand the origin of the initial irreversible capacity. The analysis reveals that the ordered arrangement of K cations after heat treatment hinders the re-intercalation of excess water in subsequent cycles.
ENERGY STORAGE MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Hiroshi Tanimura, Norihiko L. Okamoto, Takao Homma, Yusuke Sato, Akihiro Ishii, Hitoshi Takamura, Tetsu Ichitsubo
Summary: This study investigates the ultrafast optical response of VTe2 and reveals the photoinduced phase transition process. It suggests that the high-temperature phase of VTe2 is induced within a picosecond through purely electronic effect and the phase transition dynamics proceed inhomogeneously via a nucleation mode.
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.
