Article
Materials Science, Multidisciplinary
Jairo Alberto Munoz, Jose Maria Cabrera
Summary: This study investigates the microstructural changes introduced by both monotonic tensile and cyclic loads in ultrafine-grained Armco iron obtained after severe plastic deformation, revealing different microstructural gradients depending on the type of load applied. Cyclic loads result in grain size and misorientations gradients, while monotonic tensile loads lead to dislocation and grain size gradients depending on the measurement direction.
Article
Engineering, Chemical
He-Qiang Chang, Guo-Hua Zhang
Summary: Ultra-fine grain MoSi2 powders were prepared by utilizing CaO as a desulfurizer in the silicothermic reduction of MoS2, and the mechanism and kinetics were investigated. The resulting MoSi2 particles maintained the macro morphology and size of molybdenum sulfide, unaffected by the particle size of Si powder. The exothermic desulfurization reaction between CaO and gaseous SiS led to the growth of MoSi2 grains, making it challenging to separate the target product from the desulfurization product. Graphite powder or carbon felt was introduced to address this issue, resulting in a residual S content of about 0.14% and 0.16% in the prepared MoSi2 powder.
Article
Nanoscience & Nanotechnology
J. Zuo, T. Nakata, C. Xu, Y. P. Xia, H. L. Shi, X. J. Wang, G. Z. Tang, W. M. Gan, E. Maawad, G. H. Fan, S. Kamado, L. Geng
Summary: A high strength dilute Mg-0.8Al-0.1Ca-0.6Mn alloy wire was successfully developed by hot drawing, with the high strength attributed to the ultra-fine DRXed grains, coarse elongated unrecrystallized grains with dense dislocations, and nano sized Al2Ca and Al-Mn precipitates dispersed in the alloy wire.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Zi-Ren Xie, Cheng Zhang, Hu-Cheng Pan, Yu-Xin Wang, Yu-Ping Ren, Gao-Wu Qin
Summary: Electrochemical and immersion tests were conducted to characterize the bio-corrosion resistance of as-extruded Mg-Ca binary alloys with submicron grain size. The microstructures were further characterized by optical microscopy (OM), scanning electronic microscopy and transmission electron microscope (TEM). The Mg-2Ca alloy extruded at 300 degrees C (2Ca-300) exhibits the lowest current density of 1.683 mA·cm-2 and corrosion rate of 22.14 g·m-2·day-1 in simulated body fluid, which is comparable with that of pure Mg. Ca addition can reduce grain size of as-extruded Mg alloy and decrease the corrosion rate. The formed Mg2Ca phases would accelerate the local galvanic corrosion and protect the alpha-Mg matrix simultaneously due to the lower electrode potential. The lower defect density, finer grain size, and weaker basal texture intensity contribute to the excellent bi-corrosion resistance of the 2Ca-300 alloy.
Article
Materials Science, Ceramics
Hao Ding, Tong Wu, Shikai Zhao, Haibin Sun, Jiao Li, Xue Guo, Peng Wang
Summary: CeO2/BaCeO3 based electrolytes with ultra-fine grained structure show enhanced electrical performance due to lower space charge potential and diluted impurities.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Mechanical
Zhutian Xu, Rui Zhang, Linfa Peng, M. W. Fu
Summary: Multi-stage microforming is widely used in manufacturing complex miniaturized parts, but optimization design of the process is challenging. In this study, the influences of size effect, strain path change, and intragranularly misoriented grain boundary on deformation behaviors were investigated by conducting two-stage tensile tests on SS316L ultra-thin sheets. Increasing pre-strain and intersection angle reduced yield stress and hardening rate in subsequent tension, but the reduction became smaller with larger grain sizes. A crystal plasticity constitutive relation was established to accurately predict the mechanical response and microstructure evolution. This study provides insights for modeling and design of multi-stage microforming.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Nanoscience & Nanotechnology
Hidetoshi Somekawa, Jangho Yi, Hiromi Takahashi, Takanobu Hiroto, Koichi Tsuchiya
Summary: Experimental studies have revealed that many cavities are formed at grain boundaries and grain boundary triple junctions of fine-grained magnesium specimens during plastic deformation at room temperature, and the size and density of these cavities increase with the progression of deformation. The majority of cavities are controlled by plasticity, and their growth rate is similar to those observed in superplastic magnesium alloys tested at elevated temperatures.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Changzheng Li, Huan Liu, Yunchang Xin, Bo Guan, Guangjie Huang, Peidong Wu, Qing Liu
Summary: Friction stir processing (FSP) was employed to refine the coarse LPSO phases in an Mg-12.8Y-4.7 Zn alloy, resulting in densely ultrafine blocks and achieving an ultrahigh yield strength.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Qi Zhu, Qishan Huang, Yanzhong Tian, Shuchun Zhao, Yingbin Chen, Guang Cao, Kexing Song, Yanjun Zhou, Wei Yang, Ze Zhang, Xianghai An, Haofei Zhou, Jiangwei Wang
Summary: This study investigates the intrinsic deformability of defective twin boundaries in metallic materials and finds that inherent kinks on twin boundaries can facilitate the formation of secondary and hierarchical nanotwins. This defect-driven hierarchical twinning propensity is critically dependent on the kink height and is generally applicable in various metals and alloys.
Article
Chemistry, Physical
Elango Chandiran, Yukiko Ogawa, Rintaro Ueji, Hidetoshi Somekawa
Summary: The effect of grain size and strain rate on the room-temperature compression of pure magnesium was studied. It was found that the deformation mechanisms and grain-boundary sliding were significantly influenced by grain size and strain rate, and the Hall-Petch relationship broke down under certain conditions. Additionally, the deformation mode had a negligible impact on the dominant deformation mechanisms and the Hall-Petch breakdown.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Kai Hu, Jun Yi, Bo Huang, Xilei Bian, Gang Wang
Summary: This study overcomes the trade-off between strength and ductility in pure nickel materials by using grain boundary relaxation and optimizing grain size. The results show that grain boundary relaxation can improve both tensile strength and uniform elongation of nickel, and enhance the plastic deformation through controlling dislocation activities.
APPLIED MATERIALS TODAY
(2022)
Article
Nanoscience & Nanotechnology
Yun Zhang, Chen Jiang, Quan Yang, Yongjun Zhang, Shiwei Tian, Yonggang Yang, Haitao Jiang
Summary: The deformation behavior in magnesium alloy is influenced by grain orientation. This study investigated the deformation behaviors in grains with different orientations in a TRC-ZA21 alloy. The results showed that the nano-mechanical properties were affected by grain orientation and grain boundary misorientation angle. Grain orientation played a key role in determining the deformation mechanism of grains in direct contact with the nano-indenter, while the grain boundary influenced the deformation behavior of grains indirectly in contact with the nano-indenter.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Jeong Min Park, Dae Cheol Yang, Han-Jin Kim, Dong Geun Kim, Sunghak Lee, Hyoung Seop Kim, Seok Su Sohn
Summary: An equiatomic VCoNi medium-entropy alloy exhibits high sensitivity to grain-boundary strengthening, resulting in ultrafine-grain structure and impressive mechanical properties. This approach offers a new method for developing ultrastrong metallic materials with high strength and ductility.
MATERIALS RESEARCH LETTERS
(2021)
Article
Materials Science, Multidisciplinary
F. H. Duan, Y. Naunheim, C. A. Schuh, Y. Li
Summary: The study investigates the hardness and deformation behavior of body centered cubic Mo(O) alloys with grain sizes ranging from 120 to 4 nm, highlighting a peak hardness at 11 nm and a transition towards glass-like deformation behaviors as grain size decreases.
Article
Automation & Control Systems
Serafino Caruso, Giuseppina Ambrogio
Summary: Research explores a new approach to wire manufacturing by combining traditional wire drawing process with equal channel angular drawing (ECAD) technique, resulting in superior mechanical properties and fine grain structure while maintaining electrical conductivity.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Seunggyu Choi, Junhyub Jeon, Namhyuk Seo, Seung Bae Son, Seok-Jae Lee
Summary: This study investigated the effects of heating rate during solid solution heat treatment on the mechanical properties and microstructure of 7055 aluminum alloy. Dilatometric tests were conducted to control the heating rates, and a variety of methods were used to evaluate mechanical properties and microstructural features. Characteristics of precipitates for each heating rate were calculated through thermodynamic simulation, and a model for predicting mechanical properties was proposed based on the results.
METALS AND MATERIALS INTERNATIONAL
(2021)
Article
Nanoscience & Nanotechnology
Mun Sik Jeong, Tak Min Park, Seunggyu Choi, Seok-Jae Lee, Jeongho Han
Summary: A novel resetting process is proposed in this study to recover the reduced ductility of cold-worked medium-Mn steels by restoring the original microstructure of the steel through simple heat treatment. The ductility of the reset steel is successfully recovered and its strength is improved, simplifying the manufacturing process of automotive components with conflicting attributes.
SCRIPTA MATERIALIA
(2021)
Article
Materials Science, Multidisciplinary
Junhyub Jeon, Gwanghun Kim, Namhyuk Seo, Hyunjoo Choi, Hwi-Jun Kim, Min-Ha Lee, Hyun-Kyu Lim, Seung Bae Son, Seok-Jae Lee
Summary: Ni-based amorphous alloys have unique physical properties and are attracting attention in biomass plants. Machine learning algorithms are used to design and predict the thermal properties of these alloys, with a focus on determining the optimal composition.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Hyun Wook Lee, Tak Min Park, Namhyuk Seo, Seok-Jae Lee, Changmin Lee, Jeongho Han
Summary: This study aimed to develop cost-effective steels for cryogenic applications by investigating the microstructural evolutions and impact absorbed energy of a newly designed Fe-2Mn-5Ni-0.1C steel treated with quenching-tempering (QT) and quenching-lamellarizing-tempering (QLT) processes. The QLT-processed steel exhibited a higher impact absorbed energy than the QT-processed steel and Fe-9Ni steel at -196 degrees C, thanks to the active transformation-induced plasticity from retained austenite and pronounced plastic deformation of the soft martensitic matrix due to double-step tempering.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Junhyub Jeon, Namhyuk Seo, Seung Bae Son, Jae-Gil Jung, Seok-Jae Lee
Summary: This study accurately predicts the carbon diffusivity in steels using machine learning methods and provides specific insights into the prediction mechanisms of features.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Junhyub Jeon, DongEung Kim, Jun-Ho Hong, Hwi-Jun Kim, Seok-Jae Lee
Summary: We investigated various numerical methods to predict the hardness of tempered martensite in low alloy steels, including physical-based empirical equation, linear regression, shallow neural network, and deep learning approaches. We found that the physical-based empirical equation and the regression model based on the response surface method had similar prediction accuracy. The prediction accuracy of the machine learning models improved with increased complexity, but overfitting became a concern. Interestingly, a single layered neural network model with optimized hyperparameters showed similar or better hardness prediction performance compared to deep learning models with more complex architectures.
KOREAN JOURNAL OF METALS AND MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Junhyub Jeon, Namhyuk Seo, Jae -Gil Jung, Seung Bae Son, Seok-Jae Lee
Summary: This paper presents a machine learning model for predicting the Acm temperature in the Fe-C phase diagram. The dataset is analyzed and adjusted, and the model is verified and analyzed using various techniques such as cross-validation and Shapley additive explanations.
MATERIALS TRANSACTIONS
(2022)
Article
Materials Science, Multidisciplinary
Jungjoon Kim, Dongchan Min, Suwon Park, Junhyub Jeon, Seok-Jae Lee, Youngkyun Kim, Hwi-Jun Kim, Youngjin Kim, Hyunjoo Choi
Summary: Densification of amorphous powder is crucial for energy-conversion parts. Mixing powders of different sizes enhances densification. Analytical model and computational simulation were used to predict powder packing behavior, and a machine learning model achieved high packing fraction.
MATERIALS TRANSACTIONS
(2022)
Article
Materials Science, Multidisciplinary
Junhyub Jeon, Namhyuk Seo, Jae-Gil Jung, Hee-Soo Kim, Seung Bae Son, Seok-Jae Lee
Summary: In this study, a machine-learning model is used to predict austenite-grain growth, and explainable artificial intelligence (XAI) is applied to analyze the variable importance and mechanisms. With a large amount of collected data and the elimination of outliers using statistical methods, random forest regression (RFR) is selected as the model. The results show an improvement in the accuracy of the machine-learning model.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Nanoscience & Nanotechnology
Jungbin Park, Junhyub Jeon, Namhyuk Seo, Singon Kang, Seung Bae Son, Seok-Jae Lee, Jae-Gil Jung
Summary: The evolution of microstructure and mechanical properties of AISI 4340 steel during high-energy ball milling, spark plasma sintering (SPS), and post heat treatments was investigated. The study found that high-energy ball milling resulted in the formation of a nanocrystalline (-10 nm) bcc Fe matrix with segregation of alloying elements and oxide particles. The as-sintered alloy consisted of martensite-austenite (MA) constituent and fine pearlite, while the quenching after austenitization formed a microstructure composed of martensite and MA constituent. Tempering induced the decomposition of retained austenite and precipitation of cementite particles. The compressive yield strength of the as-sintered alloy was primarily strengthened by dislocations and grain boundaries/cementite lamellae, as well as secondary strengthening by oxide particles.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2023)
Article
Metallurgy & Metallurgical Engineering
Gwanghun Kim, Jungbin Park, Seok-jae Lee, Hee-soo Kim
Summary: Cu-Sn alloys, known as bronze, have been widely used for various purposes since ancient times. This study focuses on the Cu-22Sn alloy with a higher tin content than traditional bronze, which is difficult to manufacture by conventional casting methods due to the carbon solubility of copper and tin. Cu-22Sn-xC alloy was successfully fabricated using mechanical alloying and spark plasma sintering, and its microstructural characteristics were analyzed. The hardness of sintered Cu-22Sn-xC alloy was compared with Cu-22Sn alloys manufactured by rolling, casting, and forging, and B0 sintered alloy showed the highest hardness.
ARCHIVES OF METALLURGY AND MATERIALS
(2023)
Article
Metallurgy & Metallurgical Engineering
Jungbin Park, Jonghyun Jeon, Namhyuk Seo, Gwanghun Kim, Seung Bae Son, Jae-Gil Jung, Seok-Jae Lee
Summary: The stability of austenite and the strain-induced martensitic transformation behavior of a nanocrystalline FeNiCrMoC alloy were studied. The alloy was prepared by high-energy ball milling and spark plasma sintering. X-ray diffraction was used to measure the phase fraction and grain size. The grain sizes of the milled powder and sintered alloy were found to be in the nanometer range. The variation in austenite fraction during compressive deformation was measured, and the austenite stability and strain-induced martensitic transformation behavior were calculated. Hardness measurements were performed to assess the mechanical properties, and the hardness increased to 64.03 HRC when compressed up to 30%.
ARCHIVES OF METALLURGY AND MATERIALS
(2023)
Article
Metallurgy & Metallurgical Engineering
Seong-Min So, Ki-Yeon Kim, Il -Song Park, Seok-Jae Lee, Dong-Jin Yoo, Yeon-Won Kim, Min -Suk Oh
Summary: A Si-Fe-Al ternary oxide-based micropowder coating was applied to prevent the formation of Zn coating on steel during hot-dip galvanizing process, reducing welding fume and defects in Zn-galvanized steel welding. The optimized oxide coating remained stable at 470 degrees C and effectively inhibited Zn coating formation. Residual Zn could be easily removed mechanically. This coating reduced Zn fume and prevented Zn from melting in weld bead during high-temperature welding, thereby reducing welding defects. The study showed that this pretreatment simplifies manufacturing process and saves time cost-effectively.
ARCHIVES OF METALLURGY AND MATERIALS
(2023)
Article
Metallurgy & Metallurgical Engineering
Min Woo Lee, Young Sin Choi, Do Hun Kwon, Eun Ji Cha, Hee Bok Kang, Jae In Jeong, Seok Jae Lee, Hwi Jun Kim
Summary: In this study, artificial intelligence and machine learning were used to optimize the amount of metalloid elements added to a Fe-based amorphous alloy to enhance its soft magnetic properties. The effects of metalloid elements on magnetic properties, such as saturation magnetization and coercivity, were investigated through correlation analysis. Regression analysis using the Random Forest Algorithm was performed, and the coefficient of determination was found to be 0.95. Furthermore, when considering the phase information of the Fe-Si-B-P ribbon, the coefficient of determination increased to 0.98. The optimal range of metalloid addition was predicted using correlation analysis and machine learning.
ARCHIVES OF METALLURGY AND MATERIALS
(2022)
Article
Metallurgy & Metallurgical Engineering
Young-sin Choi, Do-hun Kwon, Min-woo Lee, Eun-ji Cha, Junhyup Jeon, Seok-jae Lee, Jongryoul Kim, Hwi-jun Kim
Summary: The soft magnetic properties of Fe-based amorphous alloys can be controlled through alloy design, but there is a discrepancy between experimental data and predicted values. Machine learning processes can be used to optimize the composition for further improvement of the soft magnetic properties.
ARCHIVES OF METALLURGY AND MATERIALS
(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.
