Article
Materials Science, Multidisciplinary
Zi-Qi Guan, Jing Bai, Yu Zhang, Jiang-Long Gu, Xin-Jun Jiang, Xin-Zeng Liang, Run-Kai Huang, Yu-Dong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: In this study, the effects of Co doping on the magnetostructural coupling transformation of Ni50-xCoxMn50-yTiy Heusler alloys were systematically investigated. The results show that Co doping promotes the martensitic transformation and a Ni36Co14Mn36Ti14 alloy with excellent magnetocaloric effect and mechanical properties was successfully developed.
Article
Materials Science, Multidisciplinary
Ziqi Guan, Jing Bai, Jianglong Gu, Xinzeng Liang, Die Liu, Xinjun Jiang, Runkai Huang, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: This work systematically investigates the B2 partial disordered structure, martensitic transformation, elastic, and magnetic properties of Ni8Mn4+xTi4-x (x = 0, 1, and 2) Heusler alloys through first-principles calculations. The research reveals that the alloy exhibits different magnetic and elastic behaviors under different compositions, and the occurrence of martensitic transformation depends on the energy difference between austenite and martensite.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Metallurgy & Metallurgical Engineering
Yu Zhang, Jing Bai, Ziqi Guan, Xinzeng Liang, Yansong Li, Jianglong Gu, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: The Ni2-xMn1+x+ySn1-y system with excess Mn was systematically investigated using first-principles calculations. The results showed that the excess Mn atoms occupied the sublattices of Ni or Sn, and the phase stability of the austenite decreased with an increase in Mn content. The alloys with large magnetic moments of ferrimagnetic austenite underwent martensitic transformation. Valence electrons mainly distributed around Ni or Mn-Ni atoms and bonded with normal Mn atoms. The findings provide a theoretical foundation for further development of the Ni2-xMn1+x+ySn1-y system as potential ferromagnetic shape memory alloys.
ACTA METALLURGICA SINICA-ENGLISH LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Huaxin Qi, Jing Bai, Jiaxin Xu, Shaodong Sun, Xin Liu, Ziqi Guan, Jianglong Gu, Daoyong Cong, Yudong Zhang, Claude Esling, Xiang Zhao, Liang Zuo
Summary: The effects of Cu and B doping on the martensitic transformation, mechanical, and magnetic properties of Ni-Mn-Ti-based alloys were investigated by first-principles calculations. It was found that increasing Cu content reduces the phase stability of austenite and martensite, while B doping hinders the martensitic transformation and decreases the alloy's anisotropy. The calculations of elastic constants also revealed the ductility, incompressibility, shear resistance, and normal stress resistance of the alloys.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Huaxin Qi, Jing Bai, Miao Jin, Jiaxin Xu, Xin Liu, Ziqi Guan, Jianglong Gu, Daoyong Cong, Xiang Zhao, Liang Zuo
Summary: The martensitic transformation, mechanical, and magnetic properties of Ni2Mn1.5-xCuxTi0.5 and Ni2-yCoyMn1.5-xCuxTi0.5 alloys were systematically studied using first-principles calculations. It was found that Cu doping can decrease the thermal hysteresis and anisotropy of the Ni-(Co)-Mn-Ti alloy. Increasing Mn and decreasing Ti content can improve the shear resistance and normal stress resistance, but reduce the toughness in the Ni-Mn-Cu-Ti alloy. The ductility of the Co-Cu co-doping alloy is inferior to that of the Ni-Mn-Cu-Ti and Ni-Co-Mn-Ti alloys.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2023)
Article
Chemistry, Physical
Yi-Yu Hu, Yao-Ping Xie, Lu Wu, Jian-Tao Qin, Rong-Jian Pan, Mei-Yi Yao
Summary: In this study, the mechanism of irradiation-swelling of F/M steels was investigated using a first-principles method. It was found that Frenkel pairs, specifically atomic vacancy and self-interstitial atom, affect the lattice volume of Fe-13Cr, resulting in alloy swelling. Furthermore, the faster diffusion of defects in Fe-13Cr compared to pure alpha-Fe was identified as an important factor for the good swelling resistance of Fe-13Cr.
Article
Chemistry, Physical
Xiaojie Li, Stephan Schonecker, Levente Vitos, Xiaoqing Li
Summary: This study investigates the stacking fault energies (SFE) of 29 single-phase fcc high-entropy alloys (HEAs) and finds a strong correlation between unstable SFE and shear modulus. The ratio of intrinsic SFE to unstable SFE, gamma isf/gamma usf, is identified as a characteristic measure that ranks the tendencies to exhibit deformation twinning and transformation to hexagonal close-packed martensite.
Article
Materials Science, Multidisciplinary
Binglun Han, Changlong Tan, Lei Zhao, Wenbin Zhao, Tianyou Ma, Cheng Wang, Kun Zhang, Xiaohua Tian
Summary: This study introduces a Pt and Co co-doping method to achieve high working temperature in Ni-Mn-Sn ferromagnetic shape memory alloys. By balancing the effects of Pt and Co, the working temperature is significantly improved. First-principles calculations are used to predict the impact of co-doping on the alloy properties.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Physics, Multidisciplinary
Fangzhou Zhao, Mark E. Turiansky, Audrius Alkauskas, Chris G. Van de Walle
Summary: Trap-assisted Auger-Meitner recombination is highlighted as a dominant nonradiative process in wide-band-gap materials, and a first-principles methodology is presented to determine the rates of this process in semiconductors or insulators due to defects or impurities.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Jutao Hu, Jinjing Zhang, Haiyan Xiao, Lei Xie, Guangai Sun, Huahai Shen, Pengcheng Li, Jianwei Zhang, Xiaotao Zu
Summary: This study investigated the hydrogen storage properties of high entropy alloy TiZrVMoNb using density functional theory calculations. The results showed that it has a high hydrogen storage capacity and moderate hydrogen desorption temperature, indicating great potential as hydrogen storage materials.
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
(2021)
Article
Materials Science, Multidisciplinary
Xuefeng Lu, Jupeng Qi, Junqiang Ren, Junchen Li, Hongtao Xue, Fuling Tang, Xin Guo
Summary: This paper investigates the electrochemical performance of MXene materials Zr2N and Zr2NS2 as anode materials for lithium and sodium ion batteries. The results show that Zr2N and Zr2NS2 have large specific surface area, good electrical conductivity, excellent mechanical properties, and can chemisorb lithium and sodium ions on their surfaces.
Article
Materials Science, Multidisciplinary
Rebecca J. Nicholls
Summary: Electron energy loss (EEL) spectroscopy within a transmission electron microscope can provide chemical and bonding information with atomic resolution. First principles simulations are important in interpreting spectra, especially for nanomaterials or interfaces where there are no appropriate bulk references. This paper reviews recent developments in first principles simulations of EEL spectra and highlights the potential for advances in our understanding of materials.
JOURNAL OF PHYSICS-MATERIALS
(2021)
Article
Electrochemistry
Tobias Binninger
Summary: The differential capacitance provides the most relevant thermodynamic information about an electrochemical system. Traditional approaches to describe electrochemical capacitance face difficulties in combining the ionic contribution of the electrolyte with the electronic contribution of the electrode. In this work, a new approach based on multicomponent density-functional theory (MCDFT) is developed to describe electrochemical capacitance from first principles. The present formalism unifies the treatment of double-layer capacitance and pseudocapacitance resulting from reactive processes.
ELECTROCHIMICA ACTA
(2023)
Article
Materials Science, Multidisciplinary
Xun Sun, Hualei Zhang, Dong Wang, Qiaoyan Sun, Shuangshuang Zhao, Song Lu, Wei Li, Levente Vitos, Xiangdong Ding
Summary: TiNb-based SMAs have great potential in biomaterials, but high transition temperature and limited recoverable strain are issues. A first-principles method was used to systematically study recoverable strain and transition temperature, finding that Zr can decrease M-s considerably while maintaining lattice strain. A Ti24Nb25Zr24S24Al3 HEA was designed to have large recoverable strain and low transition temperature simultaneously.
Article
Multidisciplinary Sciences
R. Salloom, S. A. Mantri, R. Banerjee, S. G. Srinivasan
Summary: The mechanical properties of Ti alloys can be improved by systematically varying the composition of the omega-phase, with the addition of beta-stabilizer solutes destabilizing the omega-phase. The Young's modulus of the omega-phase decreases with higher concentrations of beta-stabilizers, and the covalent bonding in the omega-phase compared to metallic bonding in the beta-phase suggests alloying as a promising route to enhance ductility. The study reveals that omega precipitates are not intrinsically embrittling and detrimental, and creating Ti-alloys with both good ductility and strength can be achieved by tailoring the omega precipitates' composition.
SCIENTIFIC REPORTS
(2021)
Review
Metallurgy & Metallurgical Engineering
Seo Yeon Jo, Seojun Hong, Heung Nam Han, Myoung-Gyu Lee
Summary: Computational modeling and simulation are increasingly used to predict the properties and microstructure of rolled steel products, reducing the time and cost compared to traditional methods. The finite-element method is commonly used for its numerical efficiency and precision in cold and hot rolling processes. The interdisciplinary coupling of thermomechanical-metallurgical phenomena poses a challenge to rolling simulation and modeling. This review explores recent studies on finite-element modeling for predicting shape, microstructural, and mechanical properties in steel rolling, with a focus on the progress of multiscale computational architecture.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Metallurgy & Metallurgical Engineering
Joonoh Moon, Seong-Jun Park, Kyeong-Won Kim, Hyun-Uk Hong, Heung Nam Han, Bong Ho Lee
Summary: Fe-30Mn-10.5Al-1.1C alloys with different Mo and Ni contents were studied to investigate the phase transformation behavior and mechanical properties of austenitic lightweight steels. The addition of Mo or Ni decreased the size of kappa-carbides, while complex additions of Mo and Ni resulted in the formation of ordered BCC phases and a decrease in austenite grain size. The intrinsic strength of the austenite matrix changed depending on the precipitation behavior of kappa-carbides, with 3wt% Mo or Ni decreasing the strength and complex additions increasing it again. The alloy containing both 3wt% Mo and 3wt% Ni exhibited the highest yield and tensile strength, as well as significant ductility, due to grain refinement and the formation of secondary hard phases.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Physics, Multidisciplinary
Zheng Li, Wen-Long Tian, Jun-Yi Ma, Yu Yang, Xiao-Dong Xu, Hai-Nian Han, Zhi-Yi Wei, Jiang-Feng Zhu
Summary: This study reports the first GHz high-power Kerr-lens mode-locked Yb:CaYAlO4 laser using a high-power single-mode fiber laser as the pump source. Stable unidirectional mode locking is achieved in a simple four-mirror bow-tie ring cavity, with an average power of 2.1 W, pulse duration of 88 fs, and repetition rate of 1.8 GHz at a pump power of 8 W. The high peak power and short pulse duration are crucial for coherent octave-spanning supercontinuum generation, making this laser an attractive source for optical frequency combs and micro-machining applications.
ACTA PHYSICA SINICA
(2023)
Editorial Material
Metallurgy & Metallurgical Engineering
Jeong Whan Yoon, Heung Nam Han
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Multidisciplinary Sciences
Hyun Chung, Won Seok Choi, Hosun Jun, Hyeon-Seok Do, Byeong-Joo Lee, Pyuck-Pa Choi, Heung Nam Han, Won-Seok Ko, Seok Su Sohn
Summary: Demands for ultrahigh strength in structural materials have been increasing in response to environmental issues. Maraging alloys offer high strength and toughness, but limited work hardening and uniform ductility. A new strategy involving deformable precipitates and dynamic phase transformation is demonstrated, resulting in a twofold enhancement of strength and ductility. This concept provides a promising alloy design for developing various ultrastrong metallic materials.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Sung Bo Lee, Jinwook Jung, Heung Nam Han
Summary: This study demonstrates that under electron-beam irradiation in transmission electron microscopy, gold (Au) thin film specimens undergo a transition from face-centered cubic (fcc) to body-centered cubic (bcc) structure, without the need for high temperature and pressure. The selectively thinned regions in the Au thin film specimens are heated due to the localization of energy deposition by electronic excitations, possibly caused by Auger decays. The phase transition to the bcc structure is facilitated by the thin film morphology and stabilized by crystal defects and stress development.
Article
Materials Science, Multidisciplinary
Byung Kyu Kim, Yoon Seok Ko, In-Ho Jung, Heung Nam Han, Kyung-Woo Yi, Dong-Ik Kim
Summary: The effects of alloy grain size on high-Cr ferritic stainless steel were investigated using different thicknesses of samples. The larger-grained plate sample showed a 41% reduction in oxidation rate, while the smaller-grained sheet sample exhibited a slight decrease in Cr volatilization. Numerical simulation indicated that the inhomogeneous GB-related oxidation is the major cause of the different oxidation kinetics affected by metal grain size.
Article
Materials Science, Multidisciplinary
Sung-Gyu Kang, Wonseok Jeong, Jeongin Paeng, Hwangsun Kim, Eunsol Lee, Gyeong-Su Park, Seungwu Han, Heung Nam Han, In-Suk Choi
Summary: E-beam irradiation changes the nature of interatomic bonds in a-quartz and enhances the solid-state mechanical amorphization at the nanoscale. It results in larger permanent deformations in a-quartz submicron pillars and is attributed to the enhanced mechanical amorphization and subsequent viscoplastic deformation. These findings have implications for electron-matter interactions and can be applied to new glass forming and processing technologies at the nano- and microscale.
Article
Materials Science, Multidisciplinary
Sung Bo Lee, Simoon Sung, Jinwook Jung, Heung Nam Han
Summary: The electron-beam-induced dynamics of Lomer dislocations in an Au low-angle grain boundary were observed in situ at the atomic scale. Under electron-beam irradiation, the L dislocations dissociated into different configurations and underwent mutual transitions. The grain boundary contained a step dislocation that could reverse its order under prolonged electron-beam irradiation. This transposition occurred through the decomposition and combination of dislocations, resulting in a stepwise migration of the grain boundary.
Article
Nuclear Science & Technology
Hyoung Chan Kim, Eunnam Bang, Geunsik Min, Heekyung Choi, Heung Nam Han
Summary: The integrity of tungsten plasma facing component mockups was examined before and after high heat flux test using microstructure and hardness measurement. The mockups were fabricated using gas pressure casting and hot radial pressing method, consisting of five ITER-like tungsten mono-blocks. The results showed noticeable changes in response to different heat flux conditions, with increased heat flux being of importance. Post-mortem analysis revealed a significant decrease in Vickers hardness around 300 μm and 1600 μm depths after the HHF test compared to before. The depth and magnitude of hardness change depended on the heat loading condition and the position in the tungsten block. The hardness behavior correlated with microstructural changes measured by electron backscatter diffraction (EBSD).
FUSION ENGINEERING AND DESIGN
(2023)
Article
Engineering, Mechanical
Yong Hou, Junying Min, Ali Abd El-Aty, Heung Nam Han, Myoung Gyu Lee
Summary: This study proposes a new anisotropic-asymmetric plasticity model based on the non-associated flow rule, which accurately describes the yield strength and plastic flow of sheet metals under different stress states. The results demonstrate that the proposed model has remarkable flexibility and accuracy compared to other existing models.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Physics, Applied
Jae Hun Kim, Jinuk Lee, Heung Nam Han, Boumseock Kim
Summary: Multilayer grid electrodes consisting of Cu0.7Ni0.3/Cu/Cu0.7Ni0.3 have been developed to achieve low electrical resistance and high corrosion resistance for flexible electronic devices. The thickness of the outer CuNi layer was found to affect the corrosion resistance and visibility. The electrodes prepared on the thin substrate exhibited high durability and flexibility, making them suitable for foldable usage.
JAPANESE JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Guensik Min, Yeonju Oh, Hwangsun Kim, Eunjoo Shin, Ki-Baek Roh, Jeongseok Kim, Nojun Kwak, Yanghoo Kim, Hyoung Chan Kim, Gon-Ho Kim, Heung Nam Han
Summary: In this study, a small amount of Y-rich precipitates was dispersed in a tungsten matrix through internal oxidation during spark plasma sintering, aiming to refine grain size, improve thermal stability, and increase high-temperature strength. The phase, morphology, and size of the Y-rich precipitates in the sintered tungsten were characterized by transmission electron microscopy (TEM) and small-angle neutron scattering (SANS) analyses. Furthermore, the effects of Y doping on sinterability, thermal stability, deuterium irradiation resistance, and mechanical properties were analyzed using Y-free pure tungsten specimens for comparison.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Woojin Cho, Byeong-Seok Jeong, Kyeongjae Jeong, Seung-Ho Lee, Hwangsun Kim, Jewoong Lee, Sung- Kim, Heung Nam Han
Summary: This study proposes a new approach to improve the flange formability of automotive parts by adjusting the microstructural characteristics of the material to minimize punching damage, thus increasing the hole-expansion ratio (HER).
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(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.
