Article
Nanoscience & Nanotechnology
Jing-Hua Zheng, Catalin Pruncu, Kai Zhang, Kailun Zheng, Jun Jiang
Summary: This study provides direct and systematic experimental data by revealing the evolution of dislocation density and grain size of AA6082 alloy under different conditions, using Electron Back Scattering Diffraction (EBSD) technique. The results show continuously increased geometrically necessary dislocation densities during hot deformation, as well as the presence of dislocation channel structures and dynamic recrystallization. The study is the first to visualize high temperature and high strain rate induced dislocation distributions over a relatively large area, offering valuable insights for improving physically based material models.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
C. Zhao, X. Li
Summary: The study characterized deformation of two iron-based alloys, Nitronic 60 and Tristelle 5183, using push-release bend testing, HR-EBSD, and HR-DIC methods. The results showed that high GND densities contributed to work hardening and high residual elastic strain accumulation, while heterogeneous grain/carbide size distribution led to stress concentration, causing carbide decohesion and brittle fracture of the sample.
EXPERIMENTAL MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
K. Sai Jyotheender, Chandan Srivastava
Summary: Ni coatings were electrodeposited using surfactants of different polarities. Coating with cationic surfactant had the highest fraction of low energy low angle grain boundaries (LAGBs) but also showed the highest corrosion rate. Coatings with anionic surfactants showed higher corrosion resistance due to the presence of GNDs as strings along the boundaries, which yielded lower coating strain.
Article
Nanoscience & Nanotechnology
Qinan Han, Xusheng Lei, Hao Yang, Xiaolin Yang, Zimu Su, Shao-Shi Rui, Nan Wang, Xianfeng Ma, Haitao Cui, Huiji Shi
Summary: This paper investigates the effects of temperature and load on the distribution of geometrically necessary dislocation (GND) induced by fretting fatigue in titanium alloy. The results show that both temperature and load have significant effects on GND densities, with an increase in temperature and load leading to a rise in GND densities. The peak positions of GND density correspond well with crack formation locations, indicating a close relationship between GND concentration and fretting fatigue crack formation.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Materials Science, Multidisciplinary
Akbar Heidarzadeh, Roghayeh Mohammadzadeh, Hamid Reza Jafarian, Catalin Iulian Pruncu, Aude Simar
Summary: The study reveals the contribution of GNDs and GBs to the mechanical properties of different zones in a friction stir welded pure copper joint, with higher GNDs density in the weld. Differences among zones are mainly related to the distribution of dislocations.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Engineering, Mechanical
Maoyuan Jiang, Zhengxuan Fan, Serge Kruch, Benoit Devincre
Summary: This study investigates the grain size effect in FCC polycrystalline plasticity using a multiscale modeling approach combining discrete dislocation dynamics (DDD) and crystal plasticity finite element method (CPFEM). The developed model quantitatively reproduces the deformation curves of FCC polycrystals and shows significant potential for further applications.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Mohammed Mendas, Stephane Benayoun, Mohamed Hadj Miloud, Ibrahim Zidane
Summary: This study extends the analysis of the indentation size effect (ISE) to lamellar cast irons, demonstrating that the tensile model and the concept of geometrically necessary dislocations (GNDs) can be used to predict the ISE of the pearlitic matrix within these materials. The summation of stresses associated with GNDs and statistically stored dislocations (SSDs) is shown to be more adequate in the prediction of ISE compared to considering only one work-hardening stress.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Materials Science, Multidisciplinary
Landon T. Hansen, Jay D. Carroll, Eric R. Homer, Robert H. Wagoner, Guowei Zhou, David T. Fullwood
Summary: This study examines the distribution of geometrically necessary dislocations (GNDs) in pure tantalum under simple tension using high-resolution electron backscatter diffraction. The correlations between GND density and grain boundary character, as well as triple junction character, are investigated. A novel application of two-point statistics is used to quantify and visualize the statistical geometric relationships between these entities. The mapping and assessment of the local net Burgers vectors across the sample are also conducted using a recently developed method. The quantification of near boundary gradient zones is compared using different approaches to characterize GND distribution.
MICROSCOPY AND MICROANALYSIS
(2023)
Article
Nanoscience & Nanotechnology
Shigeto Yamasaki, Hirofumi Matsuo, Tatsuya Morikawa, Masaki Tanaka
Summary: This paper proposes a method for obtaining microscopic and localized stress-strain curves by combining strain measurements using the digital image correlation (DIC) method with stress measurements using high-resolution electron backscattered diffraction (HR-EBSD). By applying georeferencing to DIC strain maps and HR-EBSD stress maps measured in a deformation-interrupted microstructure, a dataset containing 11 steps of stress-strain information in a single subset was created. This analysis allows for obtaining local stress-strain curves and strain energy maps of polycrystalline nickel alloys. A comparison of the stress-strain curves obtained from any subset in the map reveals that these curves show extremely diverse shapes depending on the location in the microstructure.
SCRIPTA MATERIALIA
(2023)
Article
Engineering, Mechanical
Yilun Xu
Summary: A non-local method for establishing GND based on a non-local domain integral has been developed and validated, showing improved accuracy in predicting material fatigue life. The comprehensive study on non-local domain effect revealed the necessity of applying the non-local GND method, as it resembles experimental observations and enhances stress field predictions compared to local methods.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Materials Science, Multidisciplinary
Wyatt A. Witzen, McLean P. Echlin, Marie-Agathe Charpagne, Tresa M. Pollock, Irene J. Beyerlein
Summary: This study investigates the intragranular distributions of geometrically necessary dislocations (GNDs) in a polycrystalline tantalum sample under shock compression loading. Using TriBeam tomography, a highly resolved 3D map of the microstructure was obtained, allowing for the examination of grain boundaries, orientations, and voids. By combining the 3D characterization, GND formulation, and a sample with approximately 6000 grains, correlations between GND density per grain and grain characteristics were analyzed. The results show that GND density increases closer to the spall plane and that grains containing voids have high GND density concentrations in the intragranular region surrounding the void.
Article
Materials Science, Multidisciplinary
Mohammad Reza Jandaghi, Hesam Pouraliakbar, Leonardo Iannucci, Vahid Fallah, Matteo Pavese
Summary: This study compared the microstructure and mechanical properties of 316L stainless steel manufactured by laser powder bed fusion using water-atomized and gas-atomized powders. The results showed that the use of water-atomized powder led to significantly higher values of tensile strength, yield strength, elongation, and toughness compared to gas-atomized powder. The water-atomized samples also exhibited a non-uniform hardness distribution, superior work-hardening rate, and higher residual stress and grain orientation spread.
MATERIALS CHARACTERIZATION
(2023)
Article
Materials Science, Multidisciplinary
Eralp Demir, Edward William Horton, Anna Kareer, David M. Collins, Mahmoud Mostafavi, David Knowles
Summary: Strain gradients are used to link microscale deformation phenomena to the mechanical response of polycrystalline materials. A unique method to compute orientation gradients has been developed, which showcases its effectiveness on an electron backscatter diffraction dataset. The proposed approach successfully eliminates sharp orientation gradients at grain boundaries.
Article
Nanoscience & Nanotechnology
P. S. M. Jena, S. K. Pradhan, S. Tripathy, B. Mahato, C. Fernando, N. Paulose, J. K. Sahu
Summary: The study on the evolution of geometrically necessary dislocation density (GND) at the gamma and primary gamma' interface during tensile deformation of turbine disk alloy revealed that GND values were highest at 800 degrees C and lowest at 350 degrees C, primarily due to the gamma/gamma' misfit value. At high temperatures, localized plastic deformation in the gamma-matrix near gamma-gamma' interfaces was identified as the main cause for necking after yielding, as evidenced by higher GND values and grain interior distortion.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Nanoscience & Nanotechnology
Xiaoyan Wang, Shaopeng Li, Yuanfei Han, Guangfa Huang, Jianwei Mao, Weijie Lu
Summary: This study investigates the role of reinforcements in the microstructural evolution of titanium matrix composites (TMCs) during high-temperature fatigue, revealing a new phenomenon of twin nucleation. The presence of reinforcements enhances dislocation accumulation and promotes the rapid diffusion of elements, leading to an increase in local stress concentration and ultimately contributing to twin nucleation. This work contributes to a better understanding of the mechanism underlying TMC fracture during high-temperature fatigue.
SCRIPTA MATERIALIA
(2021)
Article
Engineering, Mechanical
Christopher Massimo Magazzeni, Rory Rose, Chris Gearhart, Jicheng Gong, Angus J. Wilkinson
Summary: This article presents a statistical framework for optimal sampling and analysis of constant life fatigue data. Protocols are built based on Bayesian maximum entropy sampling, reducing the need for prior knowledge in data collection. Experimental validation demonstrates the applicability of these methods in laboratory testing and shows improvements in parameter estimation efficiency and accuracy.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Environmental
Xuemei Wang, Gang Wu, RuoYu Wang, Liang Xu, Haoyang Hu, Peng Sun, Xiaojian Tan, Guoqiang Liu, Jun Jiang
Summary: This study applied an integrated multistrategy, including band convergence, defect engineering, and carrier manipulation, to optimize the thermoelectric properties of SnTe. Cd-doping, Cu2Se nano-precipitate, and Sb-doping were introduced step by step to achieve the goals. The obtained compound (Sn0.86Cd0.04Sb0.1Te)0.96(Cu2Se)0.04 exhibited a high peak ZT of 1.52 at 833 K and a low thermal conductivity of 1.3 W m-1 K-1.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Junliang Liu, Robert J. Scales, Bo-Shiuan Li, Michael Goode, Bradley A. Young, Jianan Hu, Angus J. Wilkinson, David E. J. Armstrong
Summary: In this study, the microstructure and mechanical properties of two refractory high entropy alloys (RHEAs) were investigated. The alloys showed similar single-phase BCC structures in different conditions, and secondary phases with different sizes and volume fractions were formed after homogenisation heat treatment. The major secondary phase was identified as a complex C15 Laves structure. The hardness of the alloys was improved after homogenisation heat treatment, and the correlations between hardness changes and microstructural evolutions were discussed.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Abdalrhaman Koko, Thorsten H. Becker, Elsiddig Elmukashfi, Nicola M. Pugno, Angus J. Wilkinson, James Marrow
Summary: Understanding the local fracture resistance of microstructural features is crucial for the microstructure-informed design of materials. This study presents a novel approach to evaluate stress intensity factors directly from experimental measurements, using high-resolution electron backscatter diffraction. An exemplar study is conducted on a quasi-static crack propagating on low index {hkl} planes in a (001) single crystal silicon wafer.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Thermodynamics
Zipeng Yan, Longbing Yi, Haowei Xu, Shaolin Huang, Kun Song, Chunrong Pan, Jun Jiang
Summary: The mechanical performance of a segmented thermoelectric generator (TEG) is investigated using theoretical and numerical methods. The results show that the structural stress depends on the ratio of cross-sectional areas between p- and n-type TE legs, while the height ratio of different segments has a significant influence on structural stress. Thermal stress induced by unmatched thermal expansion between different segments increases rapidly with the increase of cross-sectional area and can easily exceed 20% of the total interfacial stress. The conversion efficiency and interfacial stress can be optimized by adjusting the ratio of cross-sectional areas. These findings provide a theoretical basis and guidance in the design of segmented TEGs.
JOURNAL OF THERMAL STRESSES
(2023)
Article
Materials Science, Multidisciplinary
Baptiste Gault, Heena Khanchandani, Thoudden Sukumar Prithiv, Stoichko Antonov, T. Ben Britton
Summary: Measuring local chemistry of specific crystallographic features by atom probe tomography (APT) is aided by transmission Kikuchi diffraction (TKD), but the potential structural damage caused by TKD is often ignored. Two case studies demonstrate damage in APT specimens from TKD mapping. The damage includes planar segregation of solutes and the formation of voids containing high concentrations of a specific element.
MICROSCOPY AND MICROANALYSIS
(2023)
Article
Microscopy
Abdalrhaman Koko, Vivian Tong, Angus J. Wilkinson, T. James Marrow
Summary: In high-resolution electron backscatter diffraction (HR-EBSD), the choice of a reference diffraction pattern (EBSP0) has a significant impact on the precision of strain and rotation mapping. This effect was observed in plastically deformed body-centered cubic and face-centered cubic ductile metals, as well as in brittle single-crystal silicon, indicating that it is not limited to measurement magnitude but also extends to spatial distribution. An empirical relationship between the cross-correlation parameter and angular error was established and utilized in an iterative algorithm to identify the optimal reference pattern for maximizing HR-EBSD precision.
Article
Materials Science, Multidisciplinary
Chen Jin, Ruiyang Li, Yongfu Liu, Liangliang Zhang, Jiahua Zhang, Peng Sun, Zhaohua Luo, Jun Jiang
Summary: An easy strategy is reported to improve the luminescent properties of GGG:Cr3+ phosphor by optimizing the synthesized technology. The EQE is enhanced to 43.6% and the fabricated pc-LEDs achieve a high WPE of 34.3%. These results demonstrate significant advancements in NIR phosphor materials and NIR pc-LED devices.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Engineering, Chemical
Di Xiao, Peng Sun, Jianlin Wu, Yin Zhang, Jiehua Wu, Guoqiang Liu, Haoyang Hu, Jun Hu, Xiaojian Tan, Shi He, Jun Jiang
Summary: Thermoelectric technology is an effective strategy to convert low-grade waste heat to electrical energy directly. However, there is limited research on thermoelectric generators (TEGs) for use in industrial pipelines. In this study, an arch bridge-shaped heat collector was proposed for the pipe to recover wasted thermal energy. The effects of key factors on generating performance were studied, and the experimental results showed the feasibility of using TEGs to recover waste heat from pipes.
Article
Materials Science, Multidisciplinary
Diana Avadanii, Anna Kareer, Lars Hansen, Angus Wilkinson
Summary: Instrumented spherical nanoindentation is increasingly popular in microphysical investigations. This study tests and integrates strategies for tip and machine-stiffness calibration for spherical tips. A routine for independently calibrating effective tip radius and machine stiffness is proposed, and its validity is confirmed through benchmarks and application to different materials. The impact of machine stiffness on yield stress identification methods is also evaluated.
JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Chen Jin, Ruiyang Li, Yongfu Liu, Chunhui Zhou, Peng Sun, Zhaohua Luo, Zehua Liu, Jun Jiang
Summary: An excellent FR phosphor, Gd3Al4GaO12:Cr3+, with good external quantum efficiency (EQE), suitable photoluminescence, and high thermal stability is developed by optimizing the sintering technology and chemical design. The phosphor has an emission peak at 734 nm and a band width of 70 nm, matching well with the PFR absorption band. By adjusting the flux of H3BO3 and Cr3+ concentration, the EQE reaches 47.2%, and the thermal stability remains at 96.8% at 423 K. The power-conversion efficiency of the FR pc-LED reaches 24.0% driven at 100 mA, demonstrating its high performance and promising applications in the next-generation FR light source.
MATERIALS RESEARCH BULLETIN
(2023)
Article
Engineering, Manufacturing
Ruiqiang Zhang, Jun Jiang, Jianguo Lin, Victoria A. Yardley
Summary: Thermo-mechanical uniaxial tensile testing is commonly used to characterize material properties under advanced industrial forming processes. This study investigates the effect of nonuniform temperature distributions on the variability of thermo-mechanical properties and microstructures of tested specimens.
JOURNAL OF MANUFACTURING PROCESSES
(2023)
Article
Geochemistry & Geophysics
Diana Avadanii, Lars Hansen, Katharina Marquardt, David Wallis, Markus Ohl, Angus Wilkinson
Summary: The distribution of grain-boundary types in olivine-rich rocks might affect the mechanical behavior during deformation.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Metallurgy & Metallurgical Engineering
Kai Zhang, Zhutao Shao, Joseph Robson, Yan Huang, Jinghua Zheng, Jun Jiang
Summary: A new cryogenic-hot forming process concept is proposed and proven to improve the ductility and fracture strength of magnesium alloys. This is achieved through effective grain refinement and texture weakening, making it a potential innovative method for producing high-performance magnesium components.
JOURNAL OF MAGNESIUM AND ALLOYS
(2023)
Article
Materials Science, Multidisciplinary
Ruoyu Wang, Jianfeng Cai, Qiang Zhang, Xiaojian Tan, Jiehua Wu, Guoqiang Liu, Jun Jiang
Summary: Diamond like ternary chalcopyrites MBX2 (M = Cu, Ag; B = Ga, In, Tl; X = S, Se, Te) have attracted significant research attention in the field of thermoelectrics due to their competitive performance and diverse transport properties. The ultralow thermal conductivity of AgBX2 compared to CuBX2 is explained by the mismatched atomic bonds between Ag-X and B -X pairs, resulting from the weaker bonding strength of Ag-X due to the expanded 4d orbital of Ag. This study provides important insights into the ultralow thermal conductivity of Ag-based ternary chalcopyrites and suggests a general strategy to suppress thermal conductivity in ternary compounds.
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.
