Article
Chemistry, Physical
Zhuohan Cao, Qian Liu, Qianchu Liu, Xiaobo Yu, Jamie J. Kruzic, Xiaopeng Li
Summary: This study develops a machine learning-based approach using image data to predict and reconstruct the microstructural features of LPBF fabricated Ti-6Al-4V alloy. The results show that the proposed method can accurately predict the microstructural features under different process parameters, offering potential applications in process optimization and material design in additive manufacturing.
NPJ COMPUTATIONAL MATERIALS
(2023)
Article
Physics, Applied
P. Czaja, M. J. Szczerba, E. Villa, F. Villa, V Chernenko
Summary: Intermartensitic transformations between 10, 14, and 2M martensitic phases induced by uniaxial compression and tension were investigated in a Ni50.3Mn28.7Ga21.0 single crystal. The obtained stress-temperature phase diagrams show satisfactory agreement with the Clausius-Clapeyron relationship. These results are important for the development of theory and practical applications in magnetic shape memory alloys.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Kenneth H. Eckelmeyer, Gerard M. Ludtka, Gail Mackiewicz-Ludtka, Lloyd R. Chapman, A. D. Romig
Summary: The effect of Ti content on phase transformations, microstructures, and mechanical properties of U-Ti alloys are described. Higher cooling rates are required with increasing Ti content. Full quenching results in diffusionless transformation of gamma-phase to supersaturated variants of alpha-phase. The quenching method leads to different microstructures and mechanical properties.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
H. Mei, J. C. Liu, F. Chen, Y. X. Tong, M. Zarinejad
Summary: NiTiTa shape memory alloys (SMAs) have higher corrosion resistance and better X-ray visibility compared to NiTi SMAs. This study investigates the martensitic transformation, microstructure, and shape memory effect (SME) of Ni49.6Ti45.4Ta5 SMA. After optimal thermomechanical treatment, the maximum recovery strain reaches up to 5.32% under a pre-strain of 7%.
Article
Materials Science, Multidisciplinary
Janel Chua, Vaibhav Agrawal, Timothy Breitzman, George Gazonas, Kaushik Dayal
Summary: This study applies peridynamics and phase-field modeling to predict 1-d interface motion with inertia in an elastic solid with a non-monotone stress-strain response. It finds that conventional phase-field models are unable to qualitatively simulate supersonic interface motion, indicating the limitations of their physics.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Mechanics
Marius Graf, Matthias Kuntz, Hermann Autenrieth, Felix Diewald, Ralf Mueller
Summary: This study investigates the martensite structure of steel using a phase field model, taking into account different variants and crystallographic orientation relationships. The simulations show good agreement with experimental observations, demonstrating the predictive capability of the model in predicting martensite morphology.
ARCHIVE OF APPLIED MECHANICS
(2021)
Article
Thermodynamics
Ercan Ercan, Emre Bahadir Al, Fethi Dagdelen
Summary: The microstructure, thermodynamic parameters, mechanical properties, and shape recovery properties of Cu83.5-xAl13.5Ta3Gdx (x = 0, 0.5, 1 mass%) alloy were studied. Gd addition affected the martensite phase structure, creating new phases resembling snow crystals and forming Al3GdCu intermetallic phase structures. However, Gd did not impact the high-temperature shape memory feature. The addition of Gd resulted in thinner martensite and austenite phase structures, reducing grain size and increasing microhardness in the EE1 alloy.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Physics, Multidisciplinary
Li Teng, Wen-Ting Qiu, Gong Shen
Summary: Porous materials, especially the presence of pores at the metal-air interface, significantly affect the martensitic variant structure in shape memory alloys (SMAs). Experimental studies have shown that the thinning effect resulted from the presence of pores can improve the damping performance of the alloy. A phase-field model based on the time dependent Ginzburg-Landau (TDGL) function is proposed in this study to investigate the effect of martensitic variant self-accommodation on different constrained interfaces in porous materials. The simulation results demonstrate the importance of specific surface area in obtaining fine martensitic variant structures.
ACTA PHYSICA SINICA
(2023)
Article
Chemistry, Physical
Marcin Abram, Keith Burghardt, Greg Ver Steeg, Aram Galstyan, Remi Dingreville
Summary: This study presents a self-supervised neural network approach that can predict process parameters in microstructures and uncover microstructural transitions without predefined labels. By automatically discovering microstructural transitions in different pattern-forming processes, the effectiveness of this approach is demonstrated.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
F. Hosseinifar, A. Ekrami
Summary: Cold rolling prior to inter-critical annealing can improve the mechanical properties of dual phase steel, such as ultimate tensile strength, yield strength, and hardness. This improvement is related to an increase in martensite volume fraction and refinement of ferrite grain size.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Computer Science, Artificial Intelligence
Jian Wang, Ziwei Han, Wenjing Jiang, Junseok Kim
Summary: This paper proposes a novel classification method called Phase-Field-DNN, which combines the Phase-Field model and DNN. Experimental results show that the Phase-Field-DNN model achieves higher classification accuracy than the Phase-Field model and DNN model in handling handwritten digit dataset and brain MRI classification.
PATTERN RECOGNITION
(2023)
Review
Materials Science, Multidisciplinary
Long-Qing Chen, Yuhong Zhao
Summary: The article focuses on the phase-field method as a density-based computational method for modeling and predicting temporal microstructure and property evolution during materials processes. It discusses the connections between phase-field equations and classical thermodynamics, as well as the relationships of continuum phase-field equations at different levels. Additionally, it examines the contributions of long-range interactions to domain structure evolution during phase transformations.
PROGRESS IN MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
P. Czaja, M. Kowalska, A. Brzoza-Kos, M. J. Szczerba
Summary: This paper reports on the mechanical properties observed during bending experiments conducted on quinary Ni-Mn-Ga-Co-Cu melt-spun ribbons. Different mechanical responses are noted depending on the ribbon's side to which force is applied. Substantially larger mechanical instabilities are observed when force is applied to the free side, while much lower force fluctuations are recorded when force is applied to the wheel side. The results also show that the force-displacement curve changes upon cycling, primarily by decreasing the maximum force and mechanical hysteresis.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Wei Tang, Chris M. Fancher, Peeyush Nandwana, Ke An, Andrzej Nycz, Hsin Wang, Rangasayee Kannan, Artem Trofimov, Dunji Yu, Donovan N. Leonard, Luke Meyer, Alex Plotkowski
Summary: Recent research has found that low transformation temperature (LTT) martensite steel can be used in wire arc additive manufacturing (WAAM) to produce printed walls with low tensile or compressive residual stresses. These residual stresses contribute to improved product properties. However, the thermal and mechanical properties of WAAM printed LTT martensite steel walls are not well understood.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Guoshun Qin, Chengguan Zhang, Shaobin Zhang, Xue Chen, Yongjun He
Summary: A bar of single crystal Ni-Mn-Ga shape memory alloy undergoes martensitic phase transformation through nucleation and propagation of Austenite-Martensite (A-M) interfaces. Near the A-M interface, very fine martensite twin laminates are generated due to the compatibility between the two phases. Observations on the specimen's deformation and the twin laminates reveal that the fine laminates after cooling are unstable and spontaneously transform into a single martensite variant, triggered by heating-cooling cycles.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Adrian A. Schratt, Ingo Steinbach, Volker Mohles
Summary: The Gibbs free energy of grain boundaries in Al bicrystals was explored using Molecular Dynamics simulations. A novel approach was employed where one grain is embedded in a large matrix grain with fixed misorientation. The relationship between grain boundary energy and shape was found to be influenced by temperature variations.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Metallurgy & Metallurgical Engineering
Joo-Hee Kang, Jiwon Park, Kyung Song, Chang-Seok Oh, Oleg Shchyglo, Ingo Steinbach
Summary: In this study, the partially divorced eutectic microstructure of Mg-Al alloys was investigated using various characterization techniques and simulation methods. The orientation relationships and growth behaviors between the eutectic α phase, β phase, and primary α dendrites were explored.
JOURNAL OF MAGNESIUM AND ALLOYS
(2022)
Article
Materials Science, Multidisciplinary
Uchechukwu Nwachukwu, Abdulmonem Obaied, Oliver Martin Horst, Muhammad Adil Ali, Ingo Steinbach, Irina Roslyakova
Summary: This research applies deep learning techniques to classify nickel-based superalloys based on creep strain, achieving high accuracy in classification for both phase-field data and experimental data using pre-trained neural networks and optimized hyper-parameters.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Cheng-Hui Xia, Julia Kundin, Ingo Steinbach, Sergiy Divinski
Summary: The effect of non-equilibrium vacancy on Kirkendall porosity formation was studied using a developed model of multi-component diffusion with vacancies (MDV). The results showed that the vacancy distribution strongly influences the porosity, while the diffusion profiles of substitutional components slightly depend on the intensity of source/sink.
Review
Materials Science, Multidisciplinary
Anuj Dash, Aloke Paul, Sandipan Sen, Sergiy Divinski, Julia Kundin, Ingo Steinbach, Blazej Grabowski, Xi Zhang
Summary: Recent advances in diffusion in multiprincipal element systems are reviewed, focusing on experimental and theoretical approaches to determine atomic mobilities in chemically complex multicomponent systems. The newly developed pseudobinary and pseudoternary methods provide a rigorous framework to access diffusion coefficients in alloys with arbitrary compositions. The utilization of the tracer-interdiffusion couple method enables a high-throughput determination of composition-dependent diffusion coefficients. The combination of these approaches offers a unique experimental toolbox to study diffusion of elements without suitable tracers. The pair-exchange diffusion model, which defines diffusion matrices without a reference element, is highlighted. Density-functional theory-informed calculations of diffusion properties are also discussed for the generation of extensive mobility databases for technological applications.
ANNUAL REVIEW OF MATERIALS RESEARCH
(2022)
Article
Thermodynamics
Ahmadreza Riyahi Khorasgani, Julia Kundin, Sergiy V. Divinski, Ingo Steinbach
Summary: An automated assessment procedure is used to establish a sophisticated kinetic data bank by applying consequential iteration steps through the cross-validation method. The nonlinear curve-fitting of the end-member parameters is replaced with a simple linear fitting function using the logarithmic form of the Arrhenius equation. The modifications made in this study increase the precision of the method by reducing fitting errors. The input data used are tracer diffusion coefficients in the well-studied high entropy alloy Co-Cr-Fe-Mn-Ni. The resulting parameters are in acceptable agreement with previously defined parameters in the literature and provide an efficient robust tool for the development of a kinetic data base, enabling accurate prediction of diffusion transport.
CALPHAD-COMPUTER COUPLING OF PHASE DIAGRAMS AND THERMOCHEMISTRY
(2022)
Article
Chemistry, Physical
Daniel Gaertner, Julia Kundin, Neelamegan Esakkiraja, Jasper Berndt, Adeline Durand, Josua Kottke, Stephan Klemme, Guillaume Laplanche, Gunther Eggeler, Gerhard Wilde, Aloke Paul, Ingo Steinbach, Sergiy V. Divinski
Summary: Diffusion behavior in the CoCrFeMnNi high-entropy alloy is investigated using an augmented tracer/interdiffusion couple approach. A consistent composition-dependent diffusion database is established, and a pair-diffusion model is used to describe the tracer diffusion and chemical concentration profiles. The uphill diffusion of Co observed in the experiment cannot be explained by existing kinetic and thermodynamic databases, and the vacancy wind effect is found to have a strong influence on intrinsic cross diffusion coefficients.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Materials Science, Multidisciplinary
Muhammad Adil Ali, Oleg Shchyglo, Markus Stricker, Ingo Steinbach
Summary: A crystal plasticity-phase field model based on dislocation density is used to study directional coarsening during creep in CMSX-4 Ni-based superalloys under high temperature and low stress conditions. The loss of coherency between the y matrix and y' precipitates allows the generation of geometrically necessary dislocations, leading to lattice rotation and increased creep rate in the matrix. Simulations of N-type and P-type rafting under tensile and compressive load are performed to investigate the effects of coherency loss, precipitate coalescence, and lattice rotation on creep behavior, in correlation with experimental findings.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Murali Uddagiri, Oleg Shchyglo, Ingo Steinbach, Benjamin Wahlmann, Carolin Koerner
Summary: We use multi-phase-field simulations to study the effect of remelting on microstructure evolution, particularly on nucleation of new grains during SEBM of Ni-based super alloy. The phase-field model takes into account both mass and heat transport phenomena, including release of latent heat of solidification. Remelting simulations are conducted under both as cast and homogenized conditions. Experimental observations demonstrate that remelting triggers the nucleation of new grains at the melt pool border. The simulation results provide insights into the local conditions at the melt pool border, enhancing our understanding of the nucleation mechanisms. The simulation results are validated with experimental results obtained for the Ni-20.5 mol pct Al model binary alloy.
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Yuxun Jiang, Muhammad Adil Ali, Irina Roslyakova, David Buerger, Gunther Eggeler, Ingo Steinbach
Summary: A novel approach is developed to retrieve 3D information from 2D experimental micrographs using 3D phase-field simulations and artificial intelligence. The simulations are validated to reproduce microstructural features and then used to generate simulated micrographs for training a regression model. The model is then applied to experimental micrographs to retrieve hidden 3D features. This approach is applicable to metallic materials, minerals or ceramics that can be quantitatively treated by phase-field simulations.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2023)
Article
Metallurgy & Metallurgical Engineering
Oguz Gulbay, Marc Ackermann, Alexander Gramlich, Ali Riza Durmaz, Ingo Steinbach, Ulrich Krupp
Summary: This study investigates the high-cycle-fatigue (HCF) behavior of carbide-bearing bainite (CBB) and carbide-free bainite (CFB) fabricated at different transformation temperatures. The fatigue limit of each material is determined via staircase method using a 1 kHz resonant testing machine. A new load increase test is proposed as an efficient alternative to estimate the fatigue limit in HCF regimes. The assessment of the fatigue behavior is accompanied by data-driven microstructural analyses via state-of-the-art computer vision tools. The analyses reveal that the finer carbide distribution, obtained at lower transformation temperature, enhances the overall performance of CBB. Electron backscatter diffraction (EBSD) measurements illustrate the transformation of retained austenite (RA) to martensite during deformation in CFB. The finer film-like and stable RAs, promoted by reduction in transformation temperature, enhance the HCF properties by absorbing energy required for fatigue crack propagation through improved transformation-induced plasticity. However, blocky unstable RA and/or martensite-austenite (MA) islands at prior austenite grain boundaries deteriorate the HCF properties of high-temperature CFB. Furthermore, unindexed regions in EBSD maps are effectively used to differentiate the MA islands of CFB, as validated by scanning electron microscopy (SEM) images and deep learning-based MA island segmentation.
STEEL RESEARCH INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Mohammad Reza Azadi Tinat, Murali Uddagiri, Ingo Steinbach, Inmaculada Lopez-Galilea
Summary: Computational Fluid Dynamics (CFD) simulations coupled with a Discrete Element Method (DEM) solver were used to study the dynamic behavior of the melt pool and heat transfer during the laser melting process of a nickel-based superalloy. The effects of powder inhomogeneities on the powder layer distribution were included in the CFD model. Key process parameters such as laser power, scanning speed, powder size, and powder shape were investigated for their effects on the size and homogeneity of the melt pool.
Article
Physics, Applied
L. Huo, R. Schiedung, H. Li, G. Wang, Y. Hong, A. Gruenebohm, I Steinbach
Summary: There is a need to optimize the microstructure of magnetic materials used in wind turbines and electric motors, which depends on the microstructure evolution during sintering or heat treatment. Most simulation packages do not allow for simultaneous modeling of both the structural and magnetic degrees of freedom. Therefore, we extend an open-source software project to implement the necessary micromagnetic equations and apply it to field-assisted grain growth in Sm2Co17 polycrystal films.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Multidisciplinary
Murali Uddagiri, Pankaj Antala, Oleg Shchyglo, Ingo Steinbach
Summary: A scientific benchmark test is conducted for a multi-phase-field model with double-obstacle potential by performing three-dimensional simulations of dendritic growth under directional solidification. The study explores the effects of key numerical parameters on the dendrite tip operating state, discusses uncertainties in the choice of effective interface mobility, and adapts a sharp phase-field model to achieve better convergence with reduced computational cost.
Article
Materials Science, Multidisciplinary
Julia Kundin, Ingo Steinbach, Katrin Abrahams, Sergiy V. Divinski
Summary: The newly proposed pair-exchange diffusion model for multicomponent diffusion in random alloy is analyzed in detail in this study. The model defines differences of chemical potential gradients of two elements as driving forces for interdiffusion and pair-mobilities as proportionality coefficients. It is demonstrated that a consistent definition of interdiffusion coefficients requires the fulfillment of the Gibbs-Duhem relation by the applied thermodynamic Gibbs energy description. This model is also applied to High Entropy Alloys.
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.
