Article
Materials Science, Multidisciplinary
Paul Chao, George R. Lindemann, Allen H. Hunter, Ashwin J. Shahani
Summary: This study investigates the solidification of an Al-Cu alloy to understand the emergence of patterns within eutectic colonies. A new synchrotron-based imaging method is introduced to uncover the morphological transitions in situ and in 3D. The method provides high temporal and spatial resolution, enabling direct insight into the lamella-to-rod transition mechanism.
Article
Engineering, Manufacturing
Steve Gaudez, Kouider Abdellah Abdesselam, Hakim Gharbi, Zoltan Hegedus, Ulrich Lienert, Wolfgang Pantleon, Manas Vijay Upadhyay
Summary: Dislocation structures, formed during rapid solidification in 3D printed alloys, undergo significant evolution during subsequent solid-state thermal cycling, particularly during the addition of the first few layers above the layer of interest. This finding is crucial for designing alloy microstructures with desired mechanical responses.
ADDITIVE MANUFACTURING
(2023)
Article
Nanoscience & Nanotechnology
Tomoya Nagira, Terumi Nakamura, Fumiyoshi Yoshinaka, Takahiro Sawaguchi, Yasuhiro Aoki, Masayoshi Kamai, Hidetoshi Fujii, Akihisa Takeuchi, Masayuki Uesugi
Summary: In this study, the dendrite-scale microstructural evolution of Fe-Mn-Si alloys during TIG spot welding was observed using high-spatial resolution X-ray imaging and diffraction. The solidification mode was found to significantly influence the susceptibility to solidification cracking.
SCRIPTA MATERIALIA
(2022)
Article
Materials Science, Multidisciplinary
Yeqing Wang, Jianrong Gao, Paul Chao, Nancy S. Muyanja, Ragnvald H. Mathiesen, Ashwin J. Shahani
Summary: In this study, in-situ observation of eutectic solidification in hypoeutectic Zn-Al alloys using synchrotron X-radiography revealed a cellular instability at the eutectic front induced by impurities in the liquid, confirming an alternative mechanism of eutectic colony formation.
Article
Chemistry, Physical
Xin F. Tan, Manjin Kim, Qinfen Gu, Julio Pinzon Piraquive, Guang Zeng, Stuart D. McDonald, Kazuhiro Nogita
Summary: This study investigates the effects of Na in hypo-eutectic Mg-lwt.%Si alloys for H-2 storage applications. The addition of trace amounts of Na is vital in improving the H-2 sorption kinetics, achieving a high storage capacity. The study also analyzes the hydrogen sorption mechanisms and identifies the role of Na in facilitating hydrogen diffusion.
JOURNAL OF POWER SOURCES
(2022)
Article
Polymer Science
Collin W. Foster, Sreevishnu Oruganti, Francesco Panerai
Summary: This study quantitatively analyzed the microstructural evolution and porous network development of Room Temperature Vulcanized (RTV) silicone pyrolysis at high temperatures using in situ high-temperature X-ray computed micro-tomography. The results showed that the microstructure evolution and porous network development were dependent on the heating rate, and the bulk sample volume change, porosity, pore network size, and densification were evaluated using X-ray attenuation. The findings of this study are important for the development of multi-physics models for thermal response.
POLYMER DEGRADATION AND STABILITY
(2023)
Article
Materials Science, Multidisciplinary
Shanmukha Kiran Aramanda, Kamanio Chattopadhyay, Abhik Choudhury
Summary: The paper investigates the evolution of complex patterns in the ternary Ag-Cu-Sb eutectic system, revealing the formation mechanisms of various microstructures, including three-phase eutectic and two-phase growth instabilities. Different microstructures emerge as a result of distinct crystal orientations and growth mechanisms in the presence of temperature gradients.
Article
Astronomy & Astrophysics
Christopher M. Karwin, Thomas Siegert, Jacqueline Beechert, John A. Tomsick, Troy A. Porter, Michela Negro, Carolyn Kierans, Marco Ajello, Israel Martinez-Castellanos, Albert Shih, Andreas Zoglauer, Steven E. Boggs
Summary: This article reports the measurements of the Galactic diffuse continuum emission (GDCE) observed by the Compton Spectrometer and Imager (COSI) during its flight in 2016. The results show overall good agreement with previous measurements and discuss the potential for further research using the COSI balloon data and future satellite missions.
ASTROPHYSICAL JOURNAL
(2023)
Article
Engineering, Multidisciplinary
Luo ZhiCong, Chang Jian, Wang HaiPeng
Summary: The phase selection and microstructure evolution of undercooled eutectic Ti-Si alloy were systematically investigated using the electromagnetic levitation method. The liquid-solid interface migration was detected in situ using a high-speed camera system. It was found that the eutectic growth velocity increases exponentially with undercooling. The electromagnetic stirring effect plays a significant role in accelerating the eutectic reaction velocity at low and moderate undercoolings. The microstructure of the alloy changes from primary dendritic beta-Ti phase to completely eutectic as undercoolings increase. The drop tube experiments revealed that the microstructures consist of dendritic alpha-Ti phase and eutectic phase, with the solubility of Si in the dendritic alpha-Ti phase increasing dramatically with decreased diameter.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2022)
Article
Nanoscience & Nanotechnology
X. Wang, W. Zhai, J. Y. Wang, B. Wei
Summary: The solidification process of high-entropy FeCoNi2Al0.9 alloy was modulated using 20 kHz power ultrasound with a maximum amplitude of 13 μm. The eutectic structures were composed of L12 and B2 phases growing synergistically by the K-S relationship. Increasing the ultrasound amplitude resulted in refined eutectic cell width and regular lamellar spacing, increased proportion of strictly semi-coherent L12/B2 interfaces, and suppressed solute concentration fluctuation in each eutectic phase. The steady-state cavitation and acoustic flow had a significant influence on the evolution of the eutectic microstructure. The alloy exhibited increased yield strength, ultimate strength, and total elongation compared to statically solidified alloy, providing an effective approach to improve the mechanical properties and overcome the strength-ductility trade-off in high-entropy alloys with eutectic structures.
SCRIPTA MATERIALIA
(2023)
Article
Nanoscience & Nanotechnology
Sven E. Gustafson, Darren C. Pagan, Paul A. Shade, Michael D. Sangid
Summary: Elastic micromechanical fields of a nickel-based superalloy polycrystal are tracked using high energy X-ray diffraction microscopy (HEDM) to determine intragranular deformation metrics during cyclic high temperature loading. Results show that elevated temperatures lead to complex interactions among grains, with greater recovery observed at higher temperatures.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Xiannian Zhu, Jian Chang, Pengxu Yan, Maojie Lin, Bingbo Wei
Summary: The rapid eutectic growth kinetics of undercooled liquid Ti27Ni25Co20V14Nb14 high-entropy alloy was investigated, and it was found that controlling the liquid undercooling can achieve microstructural transitions and grain refinement.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Review
Materials Science, Multidisciplinary
Chandra Sekhar Tiwary, Prafull Pandey, Suman Sarkar, Rakesh Das, Sumanta Samal, Krishanu Biswas, Kamanio Chattopadhyay
Summary: Eutectic alloys, particularly in the development of complex microstructures, show promise for being used as high-strength structural materials in engineering applications. The emergence of ultrafine eutectics and multiscale variation highlights their potential for future use in high-temperature applications.
PROGRESS IN MATERIALS SCIENCE
(2022)
Article
Nanoscience & Nanotechnology
Evan B. Baker, Sangho Jeon, Olga Shuleshova, Ivan Kaban, Yeqing Wang, Jianrong Gao, Matthias Kolbe, Michael P. SanSoucie, Douglas M. Matson
Summary: The research investigates the relationship between remelting and undercooling in Co38.2Si61.8 eutectic alloys through in situ X-ray diffraction experiments and microstructural observations. It reveals that remelting of primary solid coincides with the formation of secondary solid, mainly occurring at the supersaturated dendrite interior. The remelted solid fraction is found to be strongly correlated with secondary undercooling of the melt under various solidification conditions, indicating system-specific factors impose additional constraints.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Physical
Shriparna Mukherjee, Shanmukha Kiran Aramanda, Surafel Shiferaw Legese, Alexander Riss, Gerda Rogl, Olu Emmanuel Femi, Ernst Bauer, Peter Franz Rogl, Kamanio Chattopadhyay
Summary: The study utilized controlled in situ grown lamellar composites of (Cu2Te)(62.02)-(Sb2Te3)(37.98) to investigate a remarkable variation in thermoelectric transport properties as a function of microstructural length scale and direction-dependent arrangement of phases. Quantitative evaluation of the microstructure revealed an anisotropy in properties as a function of measurement direction in the microstructural landscape. The findings have implications for engineering thermoelectric devices in terms of power factor and output power density.
ACS APPLIED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Yih-Ren Chang, Naoki Higashitarumizu, Hayami Kawamoto, Fu-Hsien Chu, Chien-Ju Lee, Tomonori Nishimura, Rong Xiang, Wen-Hao Chang, Shigeo Maruyama, Kosuke Nagashio
Summary: A novel technique is demonstrated to achieve a high percentage of spiral SnS flakes with superior control of nucleation position by introducing atomic steps on substrates. The study reveals that the spiral SnS structure exhibits centrosymmetric characteristic, indicating that single-spiral 2D materials with monolayer step height do not guarantee an inversion symmetry breaking structure.
CHEMISTRY OF MATERIALS
(2021)
Article
Physics, Applied
Tomonori Nishimura, Toshiya Kojima, Kosuke Nagashio, Masaaki Niwa
Summary: This study discusses the ion conductive character of low-Y2O3-content yttria-stabilized zirconia (YSZ) crystallized into high-symmetric phase at relatively low temperature. The activation energy for ion conduction decreases with decreasing Y2O3 content, while conductivity still shows the highest value at certain Y2O3 content.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Taro Sasaki, Keiji Ueno, Takashi Taniguchi, Kenji Watanabe, Tomonori Nishimura, Kosuke Nagashio
Summary: Two-dimensional heterostructures have been extensively studied as NVM devices, but their operation mechanisms are not fully understood. Detailed operation mechanisms have been elucidated by exploiting FG voltage measurements, revealing three current-limiting paths controlling tunneling behavior between the channel and FG, and emphasizing the importance of the access region in achieving 2D channel/FG tunneling.
Article
Chemistry, Physical
Manabu Watanabe, Masayoshi Adachi, Hiroyuki Fukuyama
Summary: This study investigates the correlations between excess volumes, thermodynamic functions, and phase diagrams of binary alloy melts, with a focus on binary Au-X (X = Cu, Pd, and Ni) alloy melts. The densities of these alloy melts are determined accurately by employing electromagnetic levitation technique and static magnetic field. The results reveal the relationship between excess volume and excess Gibbs energy and confirm that binary alloy systems with order-disorder transitions belong to a specific group defined by V-E >= 0 and G(E) < 0. The effect of composition on excess volume is also examined, particularly in the Au-Ni system.
JOURNAL OF MOLECULAR LIQUIDS
(2022)
Article
Materials Science, Multidisciplinary
Takuya Tamura, Mingjun Li
Summary: In this study, the breakdown criteria of the compound in Nd70Cu30-50 wt pct Nd2Fe14B alloys were quantitatively analyzed by considering the specimen setting condition and vibration frequencies. It was found that there are two different vibration modes, the breakdown mode (BDM) and the simple harmonic vibration mode (SHVM), depending on the initial phase angle. The critical vibration frequencies were analyzed in terms of BDM or SHVM, taking into account the initial phase angle and the specimen location. The structures of solidified alloys at different vibration frequencies were observed and the magnetic properties were measured, showing good agreement with the solidification structures. The results may provide a guideline for scaling up in EMV processing and optimizing processing parameters.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Masayoshi Adachi, Keigo Fujiwara, Ryuta Sekiya, Hidekazu Kobatake, Makoto Ohtsuka, Hiroyuki Fukuyama
Summary: This study implemented a new liquid-phase epitaxy (LPE) technique using Ga-Al solution and improved the overall LPE process by controlling the competitive balance between polarity inversion and dissolution reaction. By investigating the dissolution of the AlN thin film into liquid Al and the growth of AlN, a designed LPE growth process successfully formed a homogeneous AlN layer on the nitrided sapphire substrate.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Thermodynamics
Manabu Watanabe, Yuki Watanabe, Chihiro Koyama, Takehiko Ishikawa, Sayaka Imaizumi, Masayoshi Adachi, Makoto Ohtsuka, Akihiko Chiba, Yuichiro Koizumi, Hiroyuki Fukuyama
Summary: Co-Cr-Mo alloys, used in biomedical implants, were studied for their density, surface tension, and viscosity using electrostatic levitation technique. It was found that there was no substantial difference in surface tension and viscosity between two CCM melts with different carbon contents.
THERMOCHIMICA ACTA
(2022)
Article
Materials Science, Multidisciplinary
Yusaku Seimiya, Yu Kudo, Ryo Shinazawa, Yuki Watanabe, Takehiko Ishikawa, Shumpei Ozawa
Summary: To accurately measure the surface tension of liquid titanium, the use of electromagnetic levitation and electrostatic levitation was studied. It was found that a high vacuum environment can inhibit the dissolution of oxygen and prevent contamination, leading to consistent results obtained from both methods.
Article
Materials Science, Multidisciplinary
Takehiko Ishikawa, Chihiro Koyama, Hirohisa Oda, Rina Shimonishi, Tsuyoshi Ito, Paul-Francois Paradis
Summary: The liquid densities of three lanthanoid sesquioxides (Tm2O3, Yb2O3, and Lu2O3) with melting temperatures above 2400 degrees C were measured using an electrostatic levitation furnace onboard the International Space Station (ISS). The samples were positively charged and their positions were controlled by Coulomb forces. Laser heating and melting were used to calculate the volume and density of the samples.
Article
Engineering, Multidisciplinary
Hidekazu Kobatake, Yuma Kurokawa, Masaya Iwabuchi, Masayoshi Adachi, Makoto Ohtsuka, Hiroyuki Fukuyama, Naohiko Sasajima, Yu Yamaguchi, Yoshiro Yamada
Summary: This article describes a preliminary study on the applicability of the dual-wavelength reflectance-ratio method for emissivity-free radiation thermometry of high-temperature liquid metals. The results showed that this method can accurately measure the temperature of metallic samples with different emissivity values.
MEASUREMENT SCIENCE AND TECHNOLOGY
(2023)
Article
Nanoscience & Nanotechnology
Takuya Tamura, Mingjun Li, Koichi Takahashi, Eisaku Inoue
Summary: In this study, the solidification of an Al-Sn alloy was performed with electromagnetic vibration (EMV) to improve the distribution of the Sn phase. It was found that EMV at a frequency of 100 Hz can refine and disperse the Sn phase homogeneously in the primary Al matrix, resulting in improved elongation in tensile tests.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
Masayoshi Adachi, Sonoko Hamaya, Daisuke Morikawa, Benjamin G. Pierce, Ahmad M. Karimi, Yuji Yamagata, Kenji Tsuda, Roger H. French, Hiroyuki Fukuyama
Summary: This paper presents a successful growth of AlN film on metal droplets using a solution-growth method, which has significant implications for the application of optoelectronic devices.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2023)
Article
Materials Science, Ceramics
Chihiro Koyama, Takehiko Ishikawa, Yuki Watanabe
Summary: The densities of molten Y2O3-Al2O3 compounds, including YAG, were determined over a wide temperature range using an electrostatic levitation furnace. The density of molten YAG varied with temperature according to a specific relationship. The molar volumes of the compounds varied linearly within the superheated temperature range, but deviated from the ideal solution model in the undercooled region due to attractive interactions between Y2O3 and Al2O3.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2023)
Article
Nanoscience & Nanotechnology
Sen Li, Masayoshi Adachi, Makoto Ohtsuka, Hiroyuki Fukuyama
Summary: We propose a new AlN crystal growth method using Fe-based fluxes. AlN single crystals were grown epitaxially on an AlN bulk substrate by a solution growth method using type 430 ferritic stainless steel flux. The impurity concentrations of carbon were significantly decreased in the synthesized crystal. The method is characterized by the use of readily available and low-cost steel-based alloys as a flux, a lower growth temperature, no high-pressure vessel requirement, and no need for waste gas detoxification equipment.
Proceedings Paper
Engineering, Electrical & Electronic
Kosuke Nagashio
Summary: Van der Waals heterostructures serve as the ideal material platform for TFETs, allowing for band-to-band tunneling dominant current at room temperature. Achieving low subthreshold swing values remains a challenge, but this work demonstrates the potential of achieving this with MoS2 heterostructure TFETs.
2021 5TH IEEE ELECTRON DEVICES TECHNOLOGY & MANUFACTURING CONFERENCE (EDTM)
(2021)
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.