Article
Materials Science, Multidisciplinary
Meimei Li, Wei-Ying Chen, Peter M. Baldo
Summary: The study on helium effects and their interactions with displacement damage in irradiated materials was conducted using in situ dual-ion beam irradiation capability with transmission electron microscopy. It was found that helium bubbles were formed and segregated within dislocation loops during helium implantation experiments, while no bubbles were observed outside the loops. However, when nickel was irradiated simultaneously with Kr ions and He ions, helium bubbles were formed uniformly in the matrix.
MATERIALS CHARACTERIZATION
(2021)
Article
Materials Science, Multidisciplinary
Yuanyuan Wang, Xin Sun, Jijun Zhao
Summary: This study examines the deformation behavior of irradiated tungsten at elevated service temperatures using mechanism-based crystal plasticity finite element framework, considering thermal softening and irradiation hardening. The model successfully predicts the engineering stress-strain response and captures the formation and evolution of shear bands.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2021)
Article
Multidisciplinary Sciences
M. A. Tunes, M. Imtyazuddin, C. Kainz, S. Pogatscher, V. M. Vishnyakov
Summary: A dual-phase Cr2AlC material was synthesized using magnetron sputtering at a temperature of 648 K, and the irradiation resistance was assessed using a 300-keV Xe ion beam in situ within a transmission electron microscope. The study found that preexisting amorphous nano-zones can be beneficial to the material under extreme environments, contrary to conventional understanding.
Article
Materials Science, Multidisciplinary
James E. Nathaniel, Gregory A. Vetterick, Osman El-Atwani, Asher Leff, Jon Kevin Baldwin, Pete Baldo, Marquis A. Kirk, Khalid Hattar, Mitra L. Taheri
Summary: This study provides experimental evidence that grain size and irradiation induced defect morphology are not directly correlated, and the addition of solute can alter the final damage state.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Lingzhe Ren, Jinpeng Lv
Summary: The influences of 90 keV H+, O+ and 1 MeV electron irradiation on the morphology, structure, defect and optoelectronic properties of unintentionally doped beta-Ga2O3 crystals were studied. H+ irradiation slightly reduced the blue luminescence due to the deactivation of V-Ga acceptors, while electron irradiation remarkably increased the blue luminescence. O+ irradiation led to the observation of a new defect with g=1.998 ESR signal and a change in appearance. Interestingly, O+ irradiation enhanced the g=1.96 shallow donor resonance, possibly due to the formation of abundant V-Ga and Si-Ga defects and/or the Si-Ga-O-i complex.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Jinpeng Lv, Xiangyu Wen, Zhenhua Zhou, Bo Zhou, Hexiang Han
Summary: This study systematically investigates the effects of O+ and N+ irradiation damage on ZnO bulk crystals, revealing the differences in ZnO damage induced by different ion irradiations. Our findings show that N+ irradiation results in a significant increase in electron concentration while O+ irradiation leads to the emergence of VZn related acceptors. Additionally, we observe the first observation of 450 nm VZn emission created by O+ irradiation.
MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
R. Boffy, L. Martel, R. Schweins, J. Somers, J. Beaucour, F. J. Bermejo
Summary: The internal structure of several alkali-borosilicate glasses when exposed to a high thermal neutron flux was studied, with different glasses showing varying resistance to irradiation. Experimental tools like Nuclear Magnetic Resonance (NMR) and Small Angle Neutron Scattering (SANS) were used for structural analysis, revealing the possibility of phase segregation in a zinc-alkali-borosilicate.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Chemistry, Physical
Hyejeong Hyun, Daseul Ham, Su Yong Lee, Jongwoo Lim
Summary: High-Ni layered oxides undergo chemomechanical evolution during high-voltage charging, leading to crystallographic defects and lattice distortions within cathode particles. However, these lattice imperfections are difficult to characterize in discharged states due to the significant recovery during discharging. This study successfully detects subtle yet persistent lattice distortions in the discharged state using synchrotron-based X-ray diffraction and Bragg coherent diffraction imaging.
ADVANCED ENERGY MATERIALS
(2023)
Article
Engineering, Electrical & Electronic
Xiaolong Zhao, Liang Chen, Wenbo Peng, Gaoming Li, Shuwen Guo, Yongning He, Xiaoping Ouyang
Summary: The performance of the p(+)-Si/n-ZnO photodetector under large reverse bias voltage and neutron irradiation effects was investigated. The detector showed good neutron tolerance and fast response capability, making it suitable for various applications that require these characteristics.
SENSORS AND ACTUATORS A-PHYSICAL
(2021)
Article
Physics, Applied
Alain Chartier, Paul Fossati, Laurent Van Brutzel, Orest Dorosh, Jacek Jagielski
Summary: The response of MgO periclase to irradiation was investigated using molecular dynamics simulations. The simulated lattice and volume swellings matched well with experimental measurements. Below 0.2 dpa, dislocation loops were formed from point defect clusters, consisting of magnesium and oxygen interstitials. Very small 1/2 110 loops in {001} planes acted as seeds for the growth of dislocation loops in {110}, {001}, and {111} planes. Above 0.2 dpa, lattice swelling decreased relative to the formation of less dense dislocation forests, while volume swelling increased rapidly due to significant voids of vacancies, up to 32 vacancies.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Multidisciplinary Sciences
Yuhua Su, Kenichi Oikawa, Takenao Shinohara, Tetsuya Kai, Takashi Horino, Osamu Idohara, Yoshitaka Misaka, Yo Tomota
Summary: Time-of-flight Bragg-edge neutron transmission imaging was used to investigate the microstructure and strain distributions in a gear treated with a newly developed two-step induction-heating method. The results showed differences in the microstructure and strain distributions between the surface and core regions of the gear under different treatment conditions.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Asha Panghal, Yogendra Kumar, P. K. Kulriya, Parasharam M. Shirage, N. L. Singh
Summary: This study demonstrates that the structural properties of La2Zr2O7 are significantly impacted by the irradiation temperature and ion fluence during ion irradiation. At lower temperatures, the degradation of crystallinity becomes more pronounced with an increase in ion fluence.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Physics, Multidisciplinary
Miyuki Yajima, Yuji Hatano, Vladimir Kh Alimov, Takeshi Toyama, Tatsuya Kuwabara, Thomas Schwarz-Selinger, Yasuhisa Oya, Alexander Spitsyn, Noriyasu Ohno
Summary: The study focused on hydrogen isotope trapping at lattice defects in neutron-irradiated tungsten. Characterization of defects revealed the presence of dislocations, monovacancies, and relatively large vacancy clusters which trapped deuterium atoms with different values of binding energy. Dependence of deuterium retention on plasma exposure temperature and damage level was observed, showing that weaker traps with smaller binding energy increased more significantly with damage level.
Article
Materials Science, Multidisciplinary
Shieren Sumarli, Efthymios Polatidis, Florencia Malamud, Matteo Busi, Claire Navarre, Reza Esmaeilzadeh, Roland Loge, Markus Strobl
Summary: Spatially resolved studies of crystalline structures, such as lattice spacings, can be conducted using neutron Bragg edge imaging. However, extracting strain distribution becomes challenging when the strain varies across the thickness of the probed specimen. This study introduces an approach to separate the transmission spectra of two different material states, which is particularly useful for operando strain characterization in powder bed additive manufacturing environments.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Materials Science, Multidisciplinary
Wei-Ying Chen, Meimei Li
Summary: Helium significantly impacts the microstructure and mechanical properties of materials in nuclear power systems. The interaction between helium and vacancies plays a crucial role in the evolution of helium bubbles and defect microstructures. Different temperatures and irradiation methods result in various forms of bubble formation and affect the structure of dislocation loops.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
David Yang, Nicholas W. Phillips, Kay Song, Clara Barker, Ross J. Harder, Wonsuk Cha, Wenjun Liu, Felix Hofmann
Summary: Corrosion is a major concern for many industries, and this study used BCDI to monitor the dissolution of a Co-Fe alloy microcrystal exposed to hydrochloric acid. The research revealed changes in the surface layer and an increase in strain in the center of the crystal during the corrosion process.
Article
Materials Science, Multidisciplinary
Kay Song, Hongbing Yu, Phani Karamched, Kenichiro Mizohata, David E. J. Armstrong, Felix Hofmann
Summary: Understanding the mechanisms of plasticity in structural steels is crucial for the operation of next-generation fusion reactors. This study focuses on the deformation behavior of FeCr and aims to differentiate the nucleation process of dislocations for initiating plasticity from their propagation through the material. The results show that the nucleation of dislocations is mainly derived from pre-existing sources and is not significantly affected by the presence of irradiation defects or Cr content.
JOURNAL OF MATERIALS RESEARCH
(2022)
Article
Chemistry, Physical
Anna Liski, Tomi Vuoriheimo, Pasi Jalkanen, Kenichiro Mizohata, Eryang Lu, Jari Likonen, Jouni Heino, Kalle Heinola, Yevhen Zayachuk, Anna Widdowson, Ko-Kai Tseng, Che-Wei Tsai, Jien-Wei Yeh, Filip Tuomisto, Tommy Ahlgren
Summary: High entropy alloys show superior radiation resistance and thermal stability, but their interaction with hydrogen can have varied effects. This study investigates the quantity of trapping sites and properties of D retention in different samples, finding higher retention in WMoTaNbV compared to W.
Article
Geochemistry & Geophysics
T. M. Kasso, M. Kytokari, M. Oinonen, K. Mizohata, J. Tahkokallio, T. Heikkila
Summary: The Fragmenta membranea manuscript fragment collection at the National Library of Finland has been difficult to date using traditional paleography methods. In this study, radiocarbon dating is applied to offer a natural scientific timeline for the parchment the manuscripts are written on. The study also evaluates the quality of the collagen and presence of contaminants in the fragments using Fourier-transform infrared spectroscopy, and discusses the importance of high-quality samples and multiple measurements in interpreting radiocarbon dating results.
Article
Chemistry, Multidisciplinary
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Markku Leskela, Matti Putkonen, Mikko Ritala
Summary: This paper presents the preparation process and characterization of boron-doped Al2O3 thin films using atomic layer deposition. The effects of deposition temperature and annealing process on the properties of the films are investigated. The boron-doped Al2O3 film deposited at 200 degrees C shows low leakage current and a dielectric constant of 5.18 when the film thickness is 70 nm.
ADVANCED MATERIALS INTERFACES
(2023)
Article
Nuclear Science & Technology
T. Vuoriheimo, A. Liski, P. Jalkanen, T. Ahlgren, K. Mizohata, K. Heinola, Y. Zayachuk, K. K. Tseng, C. W. Tsai, J. W. Yeh, F. Tuomisto
Summary: Plasma-facing components in future fusion reactors require high temperature and particle resilience. Tungsten is currently the primary material due to its properties, but better alternatives are being explored. This study investigates the effects of hydrogen isotope exchange in an equiatomic high entropy alloy (HEA), providing insight into its suitability for fusion applications.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Nuclear Science & Technology
T. Vuoriheimo, A. Liski, K. Heinola, P. Jalkanen, K. Mizohata, T. Ahlgren, J. Raisanen
Summary: Plasma edge-localized modes (ELMs) can cause fuel retention in fusion reactor vessel walls by implanting high-energy plasma particles. The impact of deuterium ions implanted into tungsten with ELM-relevant energies was investigated using ion beams. Single energy deuterium implantations were compared with sequential implantations to study the retention profile. High energy - low energy sequential implantations showed increased retention around the implantation-induced damage maximum, while low energy - high energy sequential implantations increased the retention throughout the analyzed depth.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Astronomy & Astrophysics
Lakshika Palamakumbure, Kenichiro Mizohata, Katerina Flanderova, David Korda, Antti Penttila, Tomas Kohout
Summary: Space weathering refers to the physical and chemical changes that occur in material exposed to an interplanetary environment. It can cause alterations in material spectroscopic features, leading to errors in interpreting remotely sensed data. This study simulated the solar wind effect on asteroid spectra by irradiating meteorite samples with low-energy H+ ions, and found that short-term radiation damage is the dominant factor causing spectral changes in the 1 μm region.
PLANETARY SCIENCE JOURNAL
(2023)
Article
Chemistry, Physical
Alexander Weiss, Mariia Terletskaia, Georgi Popov, Kenichiro Mizohata, Markku Leskela, Mikko Ritala, Marianna Kemell
Summary: This study addresses the limited ability to deposit conformal and scalable halide perovskite thin films by using atomic layer deposition (ALD). Two new ALD processes, SnI2 and CsSnI3, are presented in order to achieve lead-free and environmentally friendly absorber layers for perovskite solar cells (PSCs). The findings demonstrate the successful deposition of phase-pure gamma-CsSnI3 films through conversion reactions and propose an alternative method using pulsed chemical vapor deposition (pulsed CVD) SnI2 step.
CHEMISTRY OF MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Xinzhi Li, Marko Vehkamaki, Mykhailo Chundak, Kenichiro Mizohata, Anton Vihervaara, Matti Putkonen, Markku Leskela, Mikko Ritala
Summary: This article presents a study on a new type of inorganic-organic silicon-based molecular layer deposition (MLD) process, using AlCl3 and BTEB as precursors. The researchers successfully deposited hybrid films with high growth per cycle (GPC). FESEM and AFM were used to analyze the surface morphology of the films, while ATR-FTIR, ToF-ERDA, and XPS were employed to analyze the structure and composition. The storage environment of the films was found to significantly affect their performance.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Guanze He, Hongbing Yu, Phani Karamched, Junliang Liu, Felix Hofmann
Summary: Elastic interactions play a crucial role in controlling irradiation damage evolution, yet experimental investigation on this topic is largely lacking. In this study, we used transmission electron microscopy and high-resolution on-axis transmission Kikuchi diffraction techniques to study the correlation between the evolution of irradiation-induced damage structures and the associated lattice strains in self-ion irradiated pure tungsten. The results revealed different dislocation loop structures depending on the sample thickness, indicating that free surfaces restrict the formation of extended defect structures observed in thicker samples. Strain analysis using high-resolution Kikuchi diffraction demonstrated the formation of crystallographically-oriented long-range strain fluctuations above 0.01 dpa and a decrease in total elastic energy above 0.1 dpa.
SCRIPTA MATERIALIA
(2023)
Article
Chemistry, Inorganic & Nuclear
Elisa Atosuo, Miia Maentymaeki, Leevi Pesonen, Kenichiro Mizohata, Timo Hatanpaa, Markku Leskelae, Mikko Ritala
Summary: The present study investigates the atomic layer deposition (ALD) of CoF2, NiF2, and HoF3 thin films. CoF2 deposition was achieved using CoCl2(TMEDA) and NH4F as precursors, resulting in tetragonal CoF2 films with a growth per cycle (GPC) of 0.7-1.2 Å. NiF2 deposition utilized Ni(thd)(2) and TaF5 or NbF5 as precursors, producing tetragonal NiF2 films with high oxygen and hydrogen contents. HoF3 films were deposited using Ho(thd)(3) and NbF5 as precursors, yielding orthorhombic HoF3 films with low impurity contents.
DALTON TRANSACTIONS
(2023)
Article
Chemistry, Physical
Anton Vihervaara, Timo Hatanpaa, Heta-Elisa Nieminen, Kenichiro Mizohata, Mykhailo Chundak, Mikko Ritala
Summary: In this study, high purity gold films were successfully deposited on various substrate materials for the first time using thermal reductive atomic layer deposition method. The precursors used were AuCl-(PEt3) and 1,4-bis-(trimethylgermyl)-1,4-dihydropyrazine. The growth rate was measured to be 1.7 angstroms per cycle after full coverage of the film. The films exhibited low resistivity close to the bulk value and minimal impurity content. The reaction mechanism of the process was studied in situ using a quartz crystal microbalance and a quadrupole mass spectrometer.
Proceedings Paper
Acoustics
Axi Holmstrom, Topi Pudas, Jere Hyvonen, Tom Sillanpaa, Petri Lassila, Joni Makinen, Kenichiro Mizohata, Antti Kuronen, Tapio Kotiaho, Ari Salmi, Edward Haeggstrom
Summary: Increased digitalization and technological development have led to a higher demand for rare and precious metals, but mining them from the earth is becoming more challenging. Traditional urban mining methods require toxic substances and result in unwanted by-products and emissions. This study proposes a more environmentally friendly and non-toxic approach to extract metals from printed circuit boards.
2022 IEEE INTERNATIONAL ULTRASONICS SYMPOSIUM (IEEE IUS)
(2022)
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.