Article
Materials Science, Multidisciplinary
Sigurd Wenner, Constantinos Hatzoglou, Eva Anne Mortsell, Petter Asholt
Summary: High-Si aluminum foundry alloys gain strength through the formation of nanoprecipitates upon heat treatment. Room-temperature storage affects the kinetics of early aging, with Cu additions accelerating the formation of hardening precipitates. However, 1 month of room-temperature storage negates the positive effect of Cu. The solubility limits of Si and Mg during solution heat treatment temperature mainly limit the maximum achievable strength. This study contributes to understanding the solute balance, early aging kinetics, and differences between wrought and foundry alloys through transmission electron microscopy and atom probe tomography analysis.
Article
Nanoscience & Nanotechnology
Shipeng Shu, Anthony De Luca, David C. Dunand, David N. Seidman
Summary: Micro-additions of 0.25 at.% Mn and/or 0.10 at.% Mo to dilute Al-0.08Zr-0.014Sc-0.008Er-0.09Si alloys affect precipitate evolution and resulting strengths, providing solid-solution strengthening and improving ambient-temperature strength and elevated-temperature creep resistance. Mn-modified precipitates exhibit higher number density, while Mo-modified precipitates display improved coarsening-resistance. Both Mn and Mo additions enhance creep resistance at 300 degrees C, with Mn-bearing alloys showing a more significant effect.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Jae-Gil Jung, Amir R. Farkoosh, David N. Seidman
Summary: The precipitation behavior of two L1(2)-strengthened alloys with Mg and Y additions was studied. It was found that Si-added alloy forms beta-Mg2Si precipitates at around 200 degrees C, which act as nucleation sites for the L1(2)-nanoprecipitates and cause partial depletion of Si solute atoms, resulting in a microhardness peak at 475 degrees C. The Si-free alloy has superior creep properties due to a larger lattice parameter mismatch of the L1(2)-nanoprecipitates with the Al matrix provided by higher Sc/Er/Y concentrations. Both alloys exhibit slower L1(2) nanoprecipitation-kinetics and extremely high coarsening resistance.
Article
Nanoscience & Nanotechnology
Sang-Hwa Lee, Jae-Gil Jung, Sung-Il Baik, David N. Seidman, Min-Seok Kim, Young-Kook Lee, Kwangjun Euh
Summary: The research revealed that the formation and evolution of GPI and GPII zones during natural aging had a significant impact on the mechanical properties of the Al-7.6Zn-2.7Mg-2.0Cu-0.1Zr-0.07Ti alloy. The Zn/Mg atomic ratio, mean radius, number density, and volume fraction of the GP zones also played crucial roles in influencing the mechanical properties of the alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Sang-Hwa Lee, Jae-Gil Jung, Sung-Il Baik, Sung Hyuk Park, Min-Seok Kim, Young-Kook Lee, Kwangjun Euh
Summary: The addition of Ti refines the grain size, reduces phase agglomeration, and improves the strength and ductility of the alloy, with the extrusion forming a bimodal structure of fine DRXed grains and coarse unDRXed grains.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Junyang He, Xiaoxiang Wu, Yueling Guo, Surendra Kumar Makineni
Summary: This study elucidates the crucial role of Mo in a NiCoCr medium-entropy alloy, providing necessary conditions for σ-phase precipitation through the migration of recrystallized grain boundaries and segregation of Cr/Mo solutes, emphasizing Mo's role in overcoming the strength-ductility trade-off in the alloy.
SCRIPTA MATERIALIA
(2021)
Article
Chemistry, Physical
Namhyuk Seo, Junhyub Jeon, Sang-Hwa Lee, Kwangjun Euh, Su-Hyeon Kim, Tae-Young Ahn, Seung Bae Son, Seok-Jae Lee, Jae-Gil Jung
Summary: The microstructural evolution and precipitation behavior of a multicomponent Al83Zn5Cu5Mg5Li2 alloy were investigated using TEM and APT. The as-cast alloy consisted of V-Al5Cu6Mg2 and ri-Mg(Zn,Cu,Al) phases, which partially dissolved during solution treatment. Different cooling methods resulted in the formation of different precipitates. Natural aging induced the formation of solute clusters, contributing to the age-hardening of the alloys.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nuclear Science & Technology
Tiantian Wu, Peipei Zhang, Jianfeng Tang, Liang Wang, Lei Deng, Yurong Wu, Huiqiu Deng, Wangyu Hu, Xingming Zhang
Summary: In this study, the interfacial segregation behavior of solute atoms at the precipitation/matrix coherent interface in vanadium alloys was investigated using first-principles calculations. It was found that certain alloying elements tend to segregate at specific interfaces, and this segregation behavior is influenced by the atomic size effect. The findings provide insights into the development of theoretical approaches for alloy design by controlling alloying element doping.
NUCLEAR MATERIALS AND ENERGY
(2023)
Article
Materials Science, Multidisciplinary
S. Medrano, H. Zhao, B. Gault, F. De Geuser, C. W. Sinclair
Summary: The softening and strengthening effects in pre-deformed and aged Al-Mg-Cu alloys were evaluated using microscopy, mechanical testing and modeling. A refined model for work hardening response was found to accurately determine the precipitation hardening contribution. The mechanical response of these alloys was not significantly affected by Cu content, pre-deformation level or aging temperature, indicating robustness in terms of composition variations.
Article
Engineering, Electrical & Electronic
John E. Halpin, Benjamin Jenkins, Michael P. Moody, Robert W. H. Webster, Jan-Willem G. Bos, Paul A. J. Bagot, Donald A. MacLaren
Summary: The performance of thermoelectric materials is influenced by both atomic-scale chemistry and microstructural details such as grain boundaries. This study used atom-probe tomography (APT) and electron microscopies and spectroscopies to examine the elemental distribution in a TiNiCu0.1Sn thermoelectric material. The research identified two types of grain boundaries, one rough and meandering and the other regular and geometric. Cu dopant was found to segregate at both types of grain boundaries, with the rough boundaries also decorated with oxide impurity precipitates. APT revealed that Cu exists as discrete, elongated nanoprecipitates cosegregating with larger substoichiometric titanium oxide precipitates in the rough grain boundaries. These findings highlight the importance of understanding localized chemistry variations, particularly at grain boundaries, in influencing material functionality.
ACS APPLIED ELECTRONIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
E. Thronsen, S. Shah, C. Hatzoglou, C. D. Marioara, S. Wenner, S. J. Andersen, B. Holmedal, R. Holmestad
Summary: The evolution of early-stage precipitates in a 7003 aluminium alloy was investigated through artificial ageing. It was found that after 10 minutes of artificial ageing, the hardness of the precipitates decreased and their size increased, indicating the dissolution of the Guinier-Preston (GP) zones. Subsequently, as the ageing time increased, the hardness gradually increased and new precipitate phases appeared. Atomically resolved scanning transmission electron microscopy images of the disputed T' phase were also presented.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Nanoscience & Nanotechnology
T. K. Akopyan, N. A. Belov, A. A. Lukyanchuk, N. V. Letyagin, T. A. Sviridova, A. N. Petrova, A. S. Fortuna, A. F. Musin
Summary: The research found that high pressure torsion processing can lead to the formation of a nanocrystalline structure in the Al3Ca2La1.5Mn alloy, significantly increasing the microhardness of the alloy. After annealing treatment, the microhardness of the alloy further increases, attributed to precipitation hardening resulting from the decomposition of the calcium and manganese supersaturated aluminum solid solution.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
H. H. Xi, W. Q. Ming, Y. He, P. Xie, X. D. Xu, Z. Zhang, J. H. Chen
Summary: The composition and fine structure of embedded nanoscale Al particles in Al-Si alloys with Cu addition are revealed through advanced transmission electron microscopy. These particles consist of a pure Al phase and an AlCu phase, which grows at the interface between Al and Si phases. It is suggested that the Al(Cu) composite particles are directly solidified from the melt during solidification.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Nanoscience & Nanotechnology
Shipeng Shu, Anthony De Luca, David C. Dunand, David N. Seidman
Summary: The addition of a small amount of slow-diffusing W to the alloy accelerates one type of precipitation but hinders another, leading to an increase in peak-microhardness during aging without improving coarsening and creep resistance.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Sohail Shah, Elisabeth Thronsen, Constantinos Hatzoglou, Sigurd Wenner, Calin D. Marioara, Randi Holmestad, Bjorn Holmedal
Summary: Cyclic ageing at room temperature enhances the mechanical properties of aluminum alloys by continuously injecting vacancies and enabling the dynamic precipitation of fine solute clusters. These clusters, uniformly distributed throughout the material, exhibit structural similarities to GPI zones observed after low temperature ageing. The strengthening effect of solute clusters is accelerated during cyclic ageing compared to natural ageing.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Chemistry, Physical
Haesun Park, Seungho Yu, Donald J. Siegel
Summary: The research investigates the reduction or oxidation of solid electrolytes by battery electrodes, finding that most solid electrolytes are susceptible to electron injection, except for Li3BS3 which shows resistance to reduction. Comparing charge transfer stability with chemical stability allows for a comprehensive assessment of interfacial stability. This approach is demonstrated through experiments on the Li/Li2H2PO4/LGPS interface system.
ACS ENERGY LETTERS
(2021)
Article
Chemistry, Physical
Kwangnam Kim, Donald J. Siegel
Summary: This study explores potential multivalent ion solid electrolytes (SEs) based on the antiperovskite structure, considering ten SE compositions and using first-principles calculations to predict properties relevant for SE performance. Among the compounds investigated, Mg3NAs, Ca3NAs, and Ca3PSb are deemed the most promising SEs, stable against Mg or Ca anodes with low migration barriers for vacancies and interstitials, implying high conductivity may be achieved through controlled defect concentration.
CHEMISTRY OF MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Kuthuru Suresh, Darpandeep Aulakh, Justin Purewal, Donald J. Siegel, Mike Veenstra, Adam J. Matzger
Summary: By improving packing efficiency and crystal size distributions, the hydrogen storage density of metal-organic frameworks (MOFs) can be significantly enhanced, maximizing storage capacity. System model projections show that engineering crystal morphology/size or using bimodal distributions of cubic crystal sizes can surpass the current volumetric capacity of compressed storage systems.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2021)
Article
Chemistry, Physical
Kwangnam Kim, Yiliang Li, Ping-Chun Tsai, Fei Wang, Seoung-Bum Son, Yet-Ming Chiang, Donald J. Siegel
Summary: The development of solid-state batteries has been hindered by limited understanding of ion mobility control in solid electrolytes (SEs). However, the present study combines theory and experiments to explore the synthesizability of marginally stable anti-perovskite (AP) SEs, which are predicted to exhibit high ionic mobility for Li+, Na+, and K+. The study finds a linear correlation between lattice distortion and stabilization temperature, indicating that APs with the highest ionic mobility require the highest synthesis temperature. The experimental results align well with the computational predictions, suggesting that a compound's zero K decomposition energy is an efficient descriptor for synthesizing new SEs.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Multidisciplinary
Karabi Nath, Alauddin Ahmed, Donald J. Siegel, Adam J. Matzger
Summary: This study demonstrates the remarkable methane uptake of three metal-organic frameworks through experimental and computational screening. These MOFs outperform the benchmark sorbent and show potential in efficient natural gas storage. The findings highlight the utility of computational screening in identifying overlooked sorbents.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Physical
Jeffrey G. Smith, Donald J. Siegel
Summary: The desire to increase energy density and enhance safety of batteries has led to the development of solid-state batteries with solid electrolytes. The sodium solid electrolyte Na3-xSb1-xWxS4 has been reported to exhibit higher anionic conductivity than lithium solid conductors. This study investigates the contribution of coupled cation-anion dynamics on the mobility of Na-ions using ab initio molecular dynamics. The results suggest that the high conductivity of Na3-xSb1-xWxS4 is not due to the paddlewheel effect but can be well explained by a classical vacancy model and overlap of cation vibrational modes with anion librations.
CHEMISTRY OF MATERIALS
(2022)
Article
Chemistry, Physical
Chisang Park, Sorout Shalini, Alauddin Ahmed, Thomas P. Vaid, Kwangnam Kim, Adam J. Matzger, Donald J. Siegel
Summary: The inclusion of salts in metal-organic frameworks (MOFs) has been shown to increase ionic conductivities, suggesting their potential use as solid electrolytes. This study explores the mechanism and maximum loadings of including ionic liquids (ILs) in MOFs. The results suggest that electrostatic interactions contribute to the upper limit of loading and that conductivity is maximized for loadings that do not completely fill the MOF pores. The surface area and pore volume of empty MOFs are good predictors of the maximum salt loading.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Chemistry, Multidisciplinary
Karabi Nath, Alauddin Ahmed, Donald J. Siegel, Adam J. Matzger
Summary: This study demonstrates the utility and importance of using Raman spectroscopy to determine binary gas adsorption isotherms in MOF single crystals at the microscale. The technique allows for quantifying adsorption selectivity and determining the kinetics of methane adsorption, which is critical for adsorbed natural gas storage.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Steven Kiyabu, Patrick Girard, Donald J. Siegel
Summary: This study predicts the energy densities, turning temperatures, and thermodynamic stabilities of a class of potential thermal energy storage materials through high-throughput density functional theory calculations. Several stable TES materials with superior performance are identified among many salt hydrates and demonstrated at the system level. Machine learning models are developed for salt hydrate thermodynamics to provide design guidelines for maximizing energy density.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Chemistry, Physical
Ping-Chun Tsai, Sunil Mair, Jeffrey Smith, David M. M. Halat, Po-Hsiu Chien, Kwangnam Kim, Duhan Zhang, Yiliang Li, Liang Yin, Jue Liu, Saul H. H. Lapidus, Jeffrey A. A. Reimer, Nitash P. P. Balsara, Donald J. J. Siegel, Yet-Ming Chiang
Summary: Through combined experiments and modeling, the first instance of a double paddle-wheel mechanism, leading to fast sodium ion conduction in the antiperovskite Na3-xO1-x(NH2)(x)(BH4), is shown. As the concentration of amide (NH2-) cluster anions is increased, large positive deviations in ionic conductivity above that predicted from a vacancy diffusion model are observed. Using various characterization techniques, the cluster anion rotational dynamics are found to influence cation mobility, resulting in significantly higher sodium ion conductivity at x = 1 compared to the vacancy mechanism alone.
ADVANCED ENERGY MATERIALS
(2023)
Article
Chemistry, Physical
Kwangnam Kim, Donald J. Siegel
Summary: Machine learning is used to identify the features that influence ion mobility in solid-state electrolytes and quantify their relative importance. The analysis shows that lattice properties have the greatest influence on cation mobility, and identifies other important features. This research aids in the design of optimal solid electrolytes by simplifying the design space to the most important properties.
JOURNAL OF MATERIALS CHEMISTRY A
(2022)
Review
Chemistry, Multidisciplinary
Donald J. Siegel, Linda Nazar, Yet-Ming Chiang, Chao Fang, Nitash P. Balsara
Summary: Researchers have proposed a unified framework to relate atomic and continuum scale phenomena in electrolytes used in batteries. By examining the different solvation structures in liquids and solids, it has been shown that the mobility of entities affects the translation of working ions on different length scales.
TRENDS IN CHEMISTRY
(2021)
Article
Computer Science, Artificial Intelligence
Alauddin Ahmed, Donald J. Siegel
Summary: The study predicted the H-2 capacities of a large number of metal-organic frameworks using machine learning, identifying MOFs with the potential to surpass existing materials. These MOFs are typically hypothetical compounds with low density, high surface areas, void fractions, and pore volumes. The most important features for predicting H-2 uptake were found to be pore volume and void fraction.
Article
Chemistry, Physical
Mallory R. Fuhst, Donald J. Siegel
JOURNAL OF PHYSICAL CHEMISTRY C
(2020)
Article
Electrochemistry
Kyle S. Nagy, Donald J. Siegel
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
(2020)
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.
