Article
Materials Science, Multidisciplinary
M. Harwarth, G. Chen, R. Rahimi, H. Biermann, A. Zargaran, M. Duffy, M. Zupan, J. Mola
Summary: The age hardenability of Al-alloyed lightweight stainless steels with different Ni concentrations was studied, showing significant impact on microstructures and hardening response. Hardness measurements indicated significant hardening at 350 degrees Celsius, while tensile elongation in the aged condition was negatively influenced by soft ferrite regions. Guidelines for the development of a new family of lightweight precipitation-hardenable steels were provided.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
A. Zargaran, T. T. T. Trang, Gyeongbae Park, Nack J. Kim
Summary: Utilizing kappa-carbide nanoparticles to promote the formation and engineer the morphology of B2 phase, a novel precipitation hardened hot rolled lightweight steel with excellent combination of ultrahigh specific strength and ductility has been fabricated, leading to a significant enhancement in precipitation strengthening and work hardening capability.
Article
Materials Science, Multidisciplinary
Chiwon Kim, Hyun-Uk Hong, Joonoh Moon, Bong Ho Lee, Seong-Jun Park, Chang-Hoon Lee
Summary: The strengthening effect of Fe-29.1Mn-12.5Al-1.35C-4.95Cr steel through warm rolling was investigated. After warm rolling at 300 degrees C, the steel exhibited significantly increased yield and tensile strengths. The warm rolling process caused the transformation of nano-sized carbides and elongated ferrite into different phases, leading to the strengthening of the steel.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Jia Wang, Tingting Wang, Yongjie Xi, Guang Gao, Peng Sun, Fuwei Li
Summary: It is challenging to selectively and efficiently synthesize higher alcohols (C2+OH) from CO2 hydrogenation over Ni-based catalysts due to the formation of methanation. In this study, an unprecedented synthesis of C2+OH is achieved by using a K-modified Ni-Zn bimetal catalyst, which exhibits promising activity and selectivity. The in situ generation of an active K-modified Ni-Zn carbide enhances CO2 adsorption and the surface coverage of alkyl intermediates, resulting in the promotion of C-C coupling to C2+OH rather than conventional CH4. This work opens up new possibilities for CO2 hydrogenation to higher alcohols and provides valuable insights for the rational design of selective and efficient Ni-based catalysts.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2023)
Article
Nanoscience & Nanotechnology
Y. F. An, X. P. Chen, P. Ren, W. Q. Cao
Summary: A novel austenitic lightweight steel with ultra-high strength and ductility was successfully fabricated and its microstructure and mechanical properties were systematically investigated. The unique microstructure, consisting of ultra-fine recrystallized austenite grains, submicron scale B2 particles and nanoscale B2 precipitates, contributes to the superior tensile properties of the material. Furthermore, the transformation and deformation mechanisms of the B2 phase were elucidated through the study of microstructure evolution during annealing and tensile process.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Jaeeun Lee, Hwangsun Kim, Kyeongjae Jeong, Seong-Jun Park, Joonoh Moon, Sung-gyu Kang, Heung Nam Han
Summary: Fe-Al-Mn-C steels exhibit superior mechanical properties, with the formation of nanoscale precipitates like κ-carbides significantly impacting their mechanical performance. Researchers conducted thermokinetic simulations to predict phase fraction and size of precipitates, evaluated precipitation strengthening models, and calculated total yield strength considering various strengthening mechanisms.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Materials Science, Multidisciplinary
Bih-Show Lou, Yen-Yu Chen, Zih-You Wu, Yu-Chu Kuo, Jenq-Gong Duh, Jyh-Wei Lee
Summary: The Fe-Mn-Al-C lightweight steel has been extensively studied for its high strength-to-weight ratio and potential applications. This study reports a unique micrometer scale ic-carbide phase transformation induced by pack aluminization in Fe-29Mn-9Al-0.9C lightweight steel.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Metallurgy & Metallurgical Engineering
Zhi-gang Wang, Chu-lun Shen, Jian-lei Zhang, Chang-jiang Song, Qi-jie Zhai
Summary: The study demonstrates that an electric current assisted aging method can significantly increase the yield strength and ductility of low-density steel. Compared to traditional aging methods, this current-assisted aging method achieves better results in a shorter time period, mainly due to the promotion of rapid precipitation of nano-scale carbides.
Article
Chemistry, Physical
Jong-Ho Shin, Jeon-Young Song, Sung-Dae Kim, Seong-Jun Park, Young-Wha Ma, Jong-Wook Lee
Summary: In this study, high-Mn lightweight steel was manufactured and its microstructural changes and mechanical properties after annealing and aging heat treatments were investigated. The results showed that the mechanical properties of the high-Mn lightweight steel were improved after aging heat treatment. Additionally, the high-Mn lightweight steel demonstrated good performance in low-cycle fatigue life.
Article
Materials Science, Multidisciplinary
H. Y. Chen, J. Y. Juang, C. C. Wu, J. M. Yang, T. F. Liu
Summary: This study systematically investigated the feasibility of using a new welding filler material for gas tungsten arc welding of Fe-Mn-Al-C lightweight alloys. The results showed that the welded joints had high strength and uniform microhardness distribution, with the original strengthening phase preserved in the heat-affected zone. The joints exhibited excellent mechanical properties without any cracking, showing the potential for achieving high weld strength in precipitation-hardened alloys.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Multidisciplinary Sciences
Sung-Dae Kim, Seong-Jun Park, Jae Hoon Jang, Joonoh Moon, Heon-Young Ha, Chang-Hoon Lee, Hyungkwon Park, Jong-Ho Shin, Tae-Ho Lee
Summary: The study found that κ-carbide precipitates have a significant impact on the strength and ductility of aged Fe-Mn-Al-C alloys, leading to the recovery of strain hardening rate. The activation of slip systems and the planar dislocation glide are key factors in inducing strain hardening recovery in polycrystalline metals.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Multidisciplinary
Mingxiang Liu, Xiang Li, Yunhu Zhang, Changjiang Song, Qijie Zhai
Summary: The precipitation behavior of kappa-carbides in a Fe-20Mn-9Al-1.2C-1.0V austenite based lightweight steel has been studied. Cold rolling before aging precipitation can promote the precipitation of kappa-carbides and accelerate the eutectoid transformation of austenite. V element is slightly enriched in the region of kappa-carbides and affects the nucleation barrier energy. After annealing, precipitated V-carbides induce the subsequent precipitation of kappa-carbides in the form of band distribution.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
P. Chen, F. Zhang, Q. C. Zhang, J. H. Du, F. Shi, X. W. Li
Summary: The effects of the aging process on the precipitation behavior of kappa-carbides and mechanical properties of a lightweight austenitic steel were experimentally studied. The morphology of intragranular kappa-carbides changed with increasing aging temperature and time. Intergranular kappa-carbides precipitated in high-temperature-aged steels and had lath-like and lamellar morphologies. Intragranular kappa-carbide precipitation improved the yield strength, while intergranular precipitation had a negative effect on strength and ductility. The steel aged at 550°C for 1-2 hours exhibited a good strength-ductility match.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Nanoscience & Nanotechnology
Guofeng Zhang, Wei Ma, Pengfei Ji, Bing Zhang, Xing Zhang, Junsong Zhang, Xinyu Zhang, Mingzhen Ma, Riping Liu
Summary: By partial-recrystallization annealing and short aging treatment, the microstructure of cold-rolled lightweight steel is optimized, with nanosized α-carbides and non-recrystallized austenite grains containing dense dislocations. As a result, the steel exhibits high yield strength and excellent ductility.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Materials Science, Multidisciplinary
Wenbin Tian, Wenchao Dong, Shanping Lu
Summary: The effect of high temperature aging on the microstructure evolution and mechanical properties of 16Cr-25Ni superaustenitic stainless steel weld metal was investigated. The study found that different types of carbides appeared in the aged weld metal, including M6C, M12C, and M23C6 carbides. The precipitation and coarsening of these carbides weakened the precipitation strengthening effect and suppressed the dynamic strain aging, leading to superior stability of the tensile properties during aging. The evolution of impact toughness was also affected by the interdendritic precipitates, with a rapid decrease in toughness as the interdendritic region was occupied by precipitates.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
G. M. Karthik, Farahnaz Haftlang, Jaeik Kwak, Praveen Sathiyamoorthi, Alireza Zargaran, Yong-Tae Kim, Hyoung Seop Kim
Summary: This study investigates the influence of microstructures on the corrosion behavior of CuSn alloy processed by selective laser melting (SLM). The results show that the SLM microstructures affect the corrosion behavior of the CuSn alloy, with minimal effects from residual stresses, cellular segregation, and the second-phase delta (Cu41Sn11). The dislocation density and distribution are the primary controlling factors.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Farahnaz Haftlang, Alireza Zargaran, Sujung Son, Sunghak Lee, Soon-Jik Hong, Hyoung Seop Kim
Summary: In this study, the tribological performance of V10Cr10Fe45Co30Ni5 high entropy alloy (HEA) was investigated, and its relationship with the subsurface deformed area and the superficial tribo-layer were explored. The results showed that the surface and subsurface structures of the alloy changed with the applied load, leading to enhanced hardness and the formation of a protective tribo-oxide layer.
MATERIALS & DESIGN
(2022)
Article
Nanoscience & Nanotechnology
Sujung Son, Peyman Asghari-Rad, Alireza Zargaran, Wen Chen, Hyoung Seop Kim
Summary: This study successfully fabricated a nanostructured CoCrFeNi medium-entropy alloy with excellent tensile properties through cold powder consolidation and annealing techniques. The enhanced tensile strength at cryogenic temperatures can be attributed to intensive mechanical twin activities. Engineering the microstructure through subsequent annealing leads to a desirable synergy of strength and ductility, which is of great importance in structural applications.
SCRIPTA MATERIALIA
(2022)
Article
Engineering, Manufacturing
Heechan Jung, Jungwan Lee, Gang Hee Gu, Hyungsoo Lee, Seong-Moon Seo, Alireza Zargaran, Hyoung Seop Kim, Seok Su Sohn
Summary: In this study, hierarchical defect structures, including stacking faults, nano-twins, Sigma phase, and nano-precipitates, are explored by adding Si into CrCoNi alloy fabricated by the L-PBF process. The addition of Si reduces stacking fault energy and promotes segregation, resulting in improved mechanical properties. Under optimized conditions, the alloy exhibits a high yield strength of 929 MPa and moderate ductility of 14%. A post-heat treatment changes the morphology of the Sigma phase, leading to increased ductility without a loss of tensile strength.
ADDITIVE MANUFACTURING
(2023)
Article
Materials Science, Multidisciplinary
Hyeonseok Kwon, Praveen Sathiyamoorthi, Manogna Karthik Gangaraju, Alireza Zargaran, Jaemin Wang, Yoon-Uk Heo, Stefanus Harjo, Wu Gong, Byeong-Joo Lee, Hyoung Seop Kim
Summary: In this work, a novel Fe-based medium-entropy alloy was designed based on the characteristics of maraging steels. By a single-step aging at 650 celcius for 10 min, the alloy exhibited microstructures consisting of high-density nanoprecipitates and reverted FCC phase, resulting in ultrahigh yield strength and good ductility.
Article
Materials Science, Multidisciplinary
Selim Kim, Sang Yoon Song, Sang-Heon Kim, Seongwoo Kim, Jinkeun Oh, Byeong-Joo Lee, Sunghak Lee, Nack J. Kim, Alireza Zargaran, Seok Su Sohn
Summary: This study added Sb to modulate the diffusion rates of Fe and Al/Si, resulting in the formation of H-trapping voids within the coating. These voids provided pathways for the release of H atoms, improving the resistance to crack propagation during bending. The optimal design of the Al-Si coating by adjusting the Sb content and void fraction would enable extensive applications of HPF steel.
Article
Nanoscience & Nanotechnology
Jong-Kwan Lee, Hyo-Sun Jang, Alireza Zargaran, Antonio Joao Seco Ferreira Tapia, Nack Joon Kim, Byeong-Joo Lee
Summary: The poor formability of magnesium alloys at room temperature hinders their widespread industrial application. This study optimized the composition of a Mg-Zn-Ca alloy using atomistic simulation, achieving high ductility and formability but low strength. By performing thermodynamic calculations, suitable alloying elements were selected for precipitation hardening without compromising ductility and formability. This research introduces a new alloy design technique to improve strength while preserving optimized ductility and formability, with experimental validation.
SCRIPTA MATERIALIA
(2023)
Editorial Material
Materials Science, Multidisciplinary
Praveen Sathiyamoorthi, Niraj Chawake, Alireza Zargaran, Ravi Sankar Kottada
FRONTIERS IN MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Farahnaz Haftlang, Jae Bok Seol, Alireza Zargaran, Jongun Moon, Hyoung Seop Kim
Summary: Maraging structural materials have been used for centuries, but their low ductility has limited their application. In this study, a dual-phase medium-entropy Fe68Ni10Mn10Co10Ti1.5Si0.5 maraging alloy with high strength (1.6 GPa) and enhanced ductility (-25%) is developed by injecting metastable austenite into the microstructure. The combination of metastability and heterogeneity achieved through heat treatment techniques can provide a breakthrough in developing maraging materials with large ductility.
Article
Materials Science, Multidisciplinary
Tae Jin Jang, You Na Lee, Yuji Ikeda, Fritz Koermann, Ju-Hyun Baek, Hyeon-Seok Do, Yeon Taek Choi, Hojun Gwon, Jin-Yoo Suh, Hyoung Seop Kim, Byeong-Joo Lee, Alireza Zargaran, Seok Su Sohn
Summary: Complex concentrated alloys (CCAs) with a face-centered-cubic (FCC) structure can improve both strength and ductility by adding the refractory element Mo to the alloy, resulting in enhanced solid-solution strengthening and reduced stacking fault energy (SFE).
Article
Chemistry, Physical
Sang -Ho Oh, Yang-Jin Jeong, Sin-Hye Na, Jiman Kim, Alireza Zargaran, Byeong-Joo Lee
Summary: Atomic simulations and experimental observations were conducted to investigate the atomic details of the significant increase in the diffusional growth rate of A15 Nb3Sn superconducting compound with Ti addition. It was found that Ti atoms preferentially locate at Nb sites in the bulk compound and do not significantly affect the volume diffusion of Sn. Grain refinement was observed when Ti was added, which was expected to promote the effective diffusion of Sn. The main mechanism underlying the alloying effect of Ti was revealed to be grain boundary segregation and refinement. Understanding the atomic behavior of alloying elements in Nb3Sn and their effects on the diffusional growth is important for further investigation of optimal alloying strategies.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Selim Kim, Alireza Zargaran, Sunghak Lee, Nack J. Kim, Sang-Heon Kim, Seok Su Sohn
Summary: This study investigates the addition of 0.1% tin to high-strength hot press forming steel sheets to improve resistance to hydrogen embrittlement. The results show that the presence of a tin-enriched zone and voids in the coating play a crucial role in blocking hydrogen intrusion and accelerating hydrogen emission.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
K. R. Ramkumar, Hyojin Park, Jungwan Lee, Hyeonseok Kwon, R. J. Vikram, Eun Seong Kim, Alireza Zaragaran, Hyoung Seop Kim
Summary: This short communication presents the developed as-cast CoCrNi-based eutectic high entropy alloy, which achieved a balance between strength and ductility by adjusting the valence electron concentration. The alloy consists of a face-centered cubic (FCC) phase, an ordered B2 phase, and precipitates. The dislocation pile-up at the FCC/B2 interface provides a balance between strength and ductility over a wide temperature range.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Nanoscience & Nanotechnology
Farahnaz Haftlang, Alireza Zargaran, Jae Bok Seol, Jongun Moon, Peyman Asghari Rad, Eun Seong Kim, Hyoung Seop Kim
Summary: A novel maraging medium-entropy alloy was designed to achieve high tensile strength and uniform elongation at liquid nitrogen temperature by conducting a short-time martensite-to-austenite reversion treatment and adding needle-like (NiMn)(3-x)Ti-x and elliptical-shaped Ni2SiTi nano-precipitates. The alloy exhibited an ultra-high yield strength of 1.41 GPa and ultimate tensile strength of 1.88 GPa, with a uniform elongation of 14% in the reverted condition. These superior properties were attributed to the transformation-induced plasticity (TRIP)-assisted heterogeneous dual-phase microstructure strengthened by well-distributed nano-precipitates. The metastability-engineering approach can guide the design of TRIP-assisted maraging MEA to overcome the strength-ductility trade-off in extreme environments.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Tae Jin Jang, Ju-Hyun Baek, Jin-Yoo Suh, Alireza Zargaran, Seok Su Sohn
Summary: The pursuit of a superior combination of strength and ductility in metallic materials for structural applications has long been a challenge. Recently, L12 (g') precipitation-strengthened high-entropy alloys (HEAs) that undergo direct aging from cold-rolled states have exhibited exceptional strength-ductility synergy. However, the origins of this synergetic effect in direct aging are still a subject of controversy. Herein, we aim to unravel the fundamental factors contributing to the improved mechanical properties of directly aged HEAs.
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.
