Article
Metallurgy & Metallurgical Engineering
Jun Cheng, Tingting Guo, Matthew R. Barnett
Summary: This paper examines the temperature sensitivity of tensile twinning in a magnesium single crystal during nanoindentation. It is found that the generation of twinning is temperature-dependent, with a decrease in pop-in load as temperature increases. The activation energy obtained from thermal activation analysis is consistent with the observations.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Nanoscience & Nanotechnology
J. -E. Brandenburg, J. Seo, K. Eto, D. A. Molodov, S. Tsurekawa
Summary: The study used nanoindentation to investigate the local mechanical properties near 1010 tilt grain boundaries in magnesium bicrystals with different misorientation angles. It was found that critical shear-stress for the second pop-in differed substantially for grain boundaries with different structures, indicating important mechanical property variations in these boundaries.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Yu Liu, Jian Zhang, Lei Zhao, Qiang Guo
Summary: Nanolaminated graphene-aluminum composite irradiated with high energy helium ions at room temperature exhibited deformation twinning during nanoindentation, contrasting the dislocation-mediated plasticity observed in the as-fabricated composite and the elongated helium bubbles present in the deformed composite irradiated at high temperatures. A phenomenological model for helium-bubble-assisted twin formation was developed to explain the unique deformation microstructure observed in the room temperature irradiated composite, which may offer a potential method to reduce irradiation-induced embrittlement.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Huan Yao, Tianzhou Ye, Wenshan Yu, Pengfei Wang, Junmei Wu, Yingwei Wu, Ping Chen
Summary: FeCrAl alloys are proposed for nuclear fuel cladding materials to improve accident tolerance in light water reactors, with limited data published on their creep properties. This study provides atomic-scale insights into the creep behavior of nanocrystalline FeCrAl alloys, observing primary, steady state, and tertiary creeps, with a transition in creep mechanism from Coble creep to grain boundary sliding and dislocation creep with increasing stress. The impact of grain size and alloy composition on the creep mechanism transition was found to be minimal within the scope of this research.
MATERIALS & DESIGN
(2021)
Article
Nanoscience & Nanotechnology
G. S. Duan, Y. H. Chu, L. H. Song, Z. W. Guan, J. X. Zhou, R. C. Wang, X. H. Du, B. L. Wu, C. Esling
Summary: The ratcheting behavior in an extruded AZ31B magnesium alloy was investigated. Basal < a > slip, prismatic < a > slip and {10-12} extension twinning/detwinning were identified as the deformation mechanisms. The weight of the slips or twinning/detwinning affected the valley strain and ratcheting strain. The increase of slip weight resulted in a higher strain hardening rate, causing deviation from the regular ratcheting strain pattern at a stress amplitude of 105 MPa.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Ceramics
Peng Tang, Junyuan Feng, Zhenping Wan, Xiaofang Huang, Shu Yang, Longsheng Lu, Xichun Zhong
Summary: The study focused on the anisotropic properties of AlN grains using Berkovich nanoindentation, revealing a strong correlation between grain orientation, hardness, and elastic modulus. Deformation behavior was observed on specific grain orientations, with mechanisms of anisotropic pop-in events and dislocations elucidated through molecular dynamics simulation. The use of Schmid factor to determine activated slip systems proved accurate for identifying grain orientation in AlN ceramic. Plastically active regions from nanoindentation could roughly indicate crystalline orientation.
CERAMICS INTERNATIONAL
(2021)
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
Materials Science, Ceramics
Pengzhe Zhu, Baozhen Li
Summary: This study investigated the nanoindentation process of AlN textured surface using molecular dynamics simulations and found that the force and deformation behaviors are influenced by the texture parameters. Surface textures were shown to have a beneficial effect on reducing the influence of surface deformation during the indentation process.
CERAMICS INTERNATIONAL
(2021)
Article
Metallurgy & Metallurgical Engineering
Yun Zhang, Chen Jiang, Shaoheng Sun, Wei Xu, Quan Yang, Yongjun Zhang, Shiwei Tian, Xiaoge Duan, Zhe Xu, Haitao Jiang
Summary: This manuscript investigates the effects of loading direction and strain rate on the mechanical properties, microstructural characteristics, texture evolution and deformation mechanism in TRC-ZA21 magnesium alloy sheet. The results show that the mechanical properties of the alloy exhibit significant differences due to changes in loading direction and strain rate. Basal slip, extension twinning and prismatic slip contribute differently to the plastic deformation behavior and show orientation dependence and strain rate sensitivity.
ACTA METALLURGICA SINICA-ENGLISH LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Nan Xia, Cheng Wang, Yipeng Gao, Zhen-Ming Hua, Chen-Yi Ma, Chun-Feng Du, Hang Zhang, Hong-Min Zhang, Mei-Xuan Li, Min Zha, Hui-Yuan Wang
Summary: In this study, a Mg?1Zn?0.2Zr (ZK10) alloy sheet was prepared by multi-pass hot rolling and annealing, with the addition of dilute Ca to tailor the basal texture and reduce plastic anisotropy. Microstructural characterizations showed improved ductility due to the occurrence of pyramidal c+a slip in the deformed alloys. This work may offer a new strategy for developing wrought Mg alloys with enhanced ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Nicolo M. della Ventura, Chunhua Tian, Amit Sharma, Thomas E. J. Edwards, J. Jakob Schwiedrzik, Roland E. Loge, Johann Michler, Xavier Maeder
Summary: Single-crystal magnesium micropillars with a diameter of 5 µm were compressed along the [2110] direction at cryogenic temperature (T = 184 K) at different strain rates. The predominant twinning behavior of {1012} was observed, and the critical stress required for twinning was found to be significantly higher compared to previous reports at higher temperatures. The temperature dependence of the strain rate sensitivity and activation volume for twinning was determined to be constant and linearly dependent with T, respectively, and the activation energy (Q) for twinning was calculated to be 174 kJ mol-1 for T < 273 K and 72 kJ mol-1 above.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Lijun Wang, Hui Chen, Yan Liu, Renwei Zhu
Summary: The study attempts to improve the strength and ductility of DLC film by designing Cr/CrN multilayers and doping Cr into DLC film. It is found that the multilayer with a bilayer period of 10 nm exhibits the maximum strength and toughness values. The formation of high-density stacking faults in the CrN sublayers is the predominant toughening mechanism.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Ceramics
Yonglong Lai, Jiaxin Yu, Laixi Sun, Fang Wang, Qiuju Zheng, Hongtu He
Summary: This study investigates the time dependent deformation of soda lime silicate and silica glass surfaces through nanoindentation creep tests. The results show a decrease in nanomechanical properties of both glasses with holding time. Additionally, a quick recovery in the residual depth of nanoindentation imprint for both glasses is observed after the indenter tip is retracted and before atomic force microscopy.
JOURNAL OF NON-CRYSTALLINE SOLIDS
(2022)
Article
Engineering, Electrical & Electronic
Lianghao Xue, Gan Feng, Gai Wu, Fang Dong, Kang Liang, Rui Li, Shizhao Wang, Sheng Liu
Summary: This study systematically investigated the deformation mechanism of structural anisotropy in 4H-SiC film on different indentation planes, revealing that the hardness and Young's modulus vary on different planes and the formation of defects and dislocations depends on the specific indentation plane.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Chemistry, Physical
Feng Zhang, Mingcheng Sun, Baojie Sun, Fengzheng Zhang, Yikui Bai, Zheng Liu
Summary: The study reveals the competitive relationship of different deformation mechanisms in wrought AZ31 magnesium alloy during dynamic compressive experiments at temperatures between 20 and 350 °C. The results show that the c-axis of grains gradually reorient parallel to the normal direction with increasing temperature, unless DRX mechanism is activated or grains grow up. Non-basal slip and 101 over bar 2 tension twinning are the predominant deformation mechanisms at different temperature ranges. The predominant type of DRX mechanism is rotational dynamic recrystallization, which hinders the enhancement of kernel misorientation concentration region.
Article
Nanoscience & Nanotechnology
Rintaro Ueji, Hidetoshi Somekawa, Tadanobu Inoue, Toru Hara
Summary: This study reports the preferable condition for kinking in the compression of pearlitic steel. The deformation microstructure and three-dimensional reconstruction analysis reveal the mechanisms involved in the kinking process.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
Hidetoshi Somekawa, Motohiro Yuasa, Daisuke Ando, Yoshikazu Todaka
Summary: The application of large strain to Mg-9at.%Y-6at.%Zn alloy leads to the formation of high density deformation kink boundaries. Shear strain is a controllable parameter for inducing kink boundaries effectively, especially in wrought-processed alloys containing the LPSO phase.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Nutth Tuchinda, Christopher A. Schuh
Summary: The vibrational contributions to grain boundary segregation have been calculated for binary Ni polycrystals with various solutes. A multiscale approach was used to accurately assess the site energies and entropies. The results emphasize the importance of considering vibrational entropy in segregation calculations. A strong linear correlation between site segregation energy and vibrational entropy was observed in polycrystals, promising a simplification of segregation calculations in general.
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
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
Alain Reiser, Christopher A. A. Schuh
Summary: This study explores new design concepts for the launch pad to address future experimental challenges and proposes using a stiff glass launch layer instead of a standard polymer layer to improve targeting precision and experimental temperature.
Article
Materials Science, Multidisciplinary
Yannick Naunheim, Christopher A. Schuh
Summary: In nanocrystalline materials, atomic transport is accelerated by diffusion along grain boundaries and triple junctions, leading to enhanced sintering kinetics. Additionally, nanocrystalline metals have a higher surface area, allowing for greater reactivity with organic compounds during sintering. This study focuses on the sintering behavior of high-energy ball-milled nanocrystalline Ni-10Fe powder and quantitatively evaluates the interference of densification with the process of organic removal. The findings have implications for the development of powder processing routes for various nanocrystalline metals.
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
Materials Science, Multidisciplinary
Nutth Tuchinda, Christopher A. Schuh
Summary: The solute segregation spectra for grain boundary and triple junction sites in dilute Al-based binary systems are calculated using interatomic potentials and first principles, showing that triple junction segregation is dependent on the alloy or interatomic potential and can exhibit either boundary or junction preference. The segregated spectra are used to predict the effects of solute segregation on grain size, temperature, and total solute concentration, providing a tool for alloy screening and design.
PHYSICAL REVIEW MATERIALS
(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
Nanoscience & Nanotechnology
Malik Wagih, Christopher A. Schuh
Summary: This study compares the spectra of atomic sites and properties of different grain boundaries and finds that highly symmetric tilt boundaries fail to accurately capture the environments of polycrystalline grain boundaries, leading to incorrect observations and understanding of their behavior.
SCRIPTA MATERIALIA
(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.
