Article
Materials Science, Multidisciplinary
S. Chandra, A. Alankar, N. N. Kumar, M. K. Samal, V. M. Chavan
Summary: Atomistic simulations were used to investigate dislocation activity in an FCC Cu bicrystal during plain strain compression, revealing that grain boundaries act as significant barriers to dislocation motion and heterogeneous deformation in crystals leads to differences in grain orientation distributions during deformation stages. The observed local lattice rotation fields were well correlated with geometrically necessary dislocation distributions, providing unique insights into the nanoscale deformation mechanisms. Discussions on the modeling approaches' role in bridging the gap between experiments and simulations were also included.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Gashaw B. Bizana, Luis A. Barrales-Mora
Summary: Classical theories assume a linear correlation between grain boundary curvature and velocity, but recent experimental observations suggest a more complex relationship in polycrystalline materials. Molecular dynamics simulations of nanosized polycrystalline Al annealing were used to determine the velocity and curvature of approximately 12,000 grain boundaries. The study revealed differences in kinetics behavior at the grain and grain-boundary levels, with a clear correlation between grain boundary curvature and migration direction. However, when considering all grain boundaries, the correlation between velocity and curvature was found to be low, indicating the complexity of grain boundary migration. Factors such as grain boundary character, defect distributions, and stress distribution between neighboring grains were found to influence grain boundary migration behavior.
Article
Engineering, Mechanical
Anping Hua, Junhua Zhao
Summary: Studies have found that the change in shear direction can cause a transition from grain boundary migration to sliding in nanocrystalline metals. This transition is caused by the competition between the nucleation energies of disconnection and surface step.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Engineering, Mechanical
Chuanlong Xu, Xiaobao Tian, Wentao Jiang, Qingyuan Wang, Haidong Fan
Summary: This study investigates the migration mechanisms of symmetric tilt grain boundaries (STGBs) in magnesium using molecular dynamic simulations. The results show that the migration mechanisms of grain boundaries are significantly influenced by their structure, with small angle STGBs migrating through twin nucleation and growth, large angle STGBs migrating through the glide of grain boundary dislocations, and medium angle STGBs transforming into twin boundaries through the emission of lattice dislocations/stacking faults.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Nanoscience & Nanotechnology
Huhu Su, Xinzhe Zhou, Shijian Zheng, Hengqiang Ye, Zhiqing Yang
Summary: The formation and evolution of basal-prismatic/prismatic-basal (BP/PB) interfaces in a Mg alloy under cyclic deformation were studied and modeled based on atomic-resolution experimental observations and interfacial defects theory. It was found that BP/PB interfaces could be formed by emission of specific dislocations and twinning disconnections, and could transform into twin boundaries. The experimental results offer insights into the dislocation-assisted mechanisms of formation and evolution of BP/PB interfaces in hexagonal-close-packed materials.
SCRIPTA MATERIALIA
(2022)
Article
Automation & Control Systems
Vardan Hoviki Vardanyan, Barbara S. Linke, Herbert M. Urbassek
Summary: In this study, the deformation of a nano-sized polycrystalline Al bar under the action of vice plates was investigated using molecular dynamics simulation. Fine-grained samples showed deformation mainly caused by grain-boundary processes, while coarse-grained samples exhibited deformation due to both grain-boundary processes and dislocation plasticity. The distortion of the samples was characterized by the motion of the grains' center-of-mass, with grain rotation playing a key role in surface roughening post-loading process. Additionally, grain rearrangements during load release significantly contributed to the final sample distortion.
INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Akarsh Verma, Oliver K. Johnson, Gregory B. Thompson, Ian Chesser, Shigenobu Ogata, Eric R. Homer
Summary: This study examines non-Arrhenius grain boundary migration, referred to as antithermal migration, in an incoherent twin & sigma;3 [111] 60 degrees (11 8 5) nickel grain boundary. Molecular dynamics simulations are used to investigate the effect of various factors on migration, and a classical model for grain boundary migration is employed to analyze the results. The findings reveal that the migration mechanisms of the grain boundaries exhibit low apparent barrier heights and show similarities in behavior across different interatomic potentials.
Article
Materials Science, Multidisciplinary
Pauline Simonnin, Daniel K. Schreiber, Blas P. Uberuaga, Kevin M. Rosso
Summary: Grain boundary diffusion and metal mobility in alloys play a crucial role in material performance. Through molecular dynamics simulations, it was found that atomic diffusion within grain boundaries is much faster than in the bulk, exhibiting typical Arrhenius behavior. The diffusion of chromium is faster in the bulk but slower in grain boundaries due to the formation of high cohesive energy clusters. Additionally, the temperature-dependent grain boundary migration is significantly influenced by the alloying element.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Anping Hua, Junhua Zhao, Jian Zhang, Peishi Yu, Ning Wei, Wanlin Guo
Summary: The reversibility of the representative Sigma 11(113) grain boundary migration in copper bicrystals under cyclic shear strongly depends on their grain sizes, with a transition mechanism from fully reversible disconnection-mediated migration to irreversible structural damage. The study also developed a refined disconnection model considering grain size to predict migration behavior and interpret the forming mechanism of disconnection pair grooving (DPG).
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Engineering, Mechanical
Qishan Huang, Qingkun Zhao, Haofei Zhou, Wei Yang
Summary: Grain boundaries play a crucial role in the mechanical behaviors of nanocrystalline materials, and their deformation mechanisms are closely related to grain boundary misorientation. In this study, the relationship between grain boundary misorientation and deformation mechanisms was investigated through large-scale molecular dynamic simulations in face-centered cubic metals. An energetic model was developed to predict the critical grain boundary misorientation at which grain boundary sliding surpasses grain boundary migration.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Chunfeng Du, Yipeng Gao, Min Zha, Cheng Wang, Hailong Jia, Hui-Yuan Wang
Summary: Grain boundary mediated plasticity, such as grain rotation and grain boundary sliding, is crucial in determining the deformation behavior of polycrystals, especially in nanocrystalline metals or plastic deformation at high temperatures. However, the mechanism of deformation-induced grain rotation has not been well understood due to the lack of a theoretical framework. This study introduces a disclination-based description and shows that crystal rotation can be conveniently captured through the characteristic rotational vector of a disclination. The topological defect theory provides a framework for treating grain boundary mediated plasticity as topological reactions between dislocations and disclinations, enabling accurate predictions of grain/subgrain rotation using the reformulated Frank-Bilby equation.
Article
Materials Science, Multidisciplinary
Amirreza Kazemi, Shengfeng Yang
Summary: The influence of dopants on grain boundary migration depends on the character of the grain boundary, with some showing negligible effect and others exhibiting a strengthening effect. The atomic-level mechanisms of grain boundary migration were identified for both pure aluminum and magnesium-doped aluminum alloys.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Tingting Yu
Summary: This study presents atomistic simulations revealing that an increase in driving force may result in slower grain boundary movement and switches in the mode of grain boundary shear coupling migration. Shear coupling behavior is found to effectively alleviate stress and holds potential for stress relaxation and microstructure manipulation in materials.
COMPUTATIONAL MATERIALS SCIENCE
(2024)
Article
Physics, Condensed Matter
Zhangyong Chang, Zhigang Xiao, Zhiqiang Liu, Zhenhua Chen, Long Huang, Yuxia Zhang, Cuiling Hou
Summary: Through molecular dynamics simulations, we investigated the nucleation mechanism of grown-in dislocations during the directional solidification of silicon with carbon impurity. The carbon impurity atoms were found to segregate to crystal boundary groove, leading to the formation of stacking faults and Shockley partial dislocations. These findings are significant for reducing the dislocation density of multicrystalline silicon.
PHYSICA B-CONDENSED MATTER
(2023)
Article
Materials Science, Multidisciplinary
Genchun He, Chao Xu, Chunmei Liu, Huaping Liu
Summary: This study systematically investigated the effect of symmetrical (001) tilt grain boundaries on the hardness of diamond and revealed that the misorientation angle plays a crucial role, with smaller angles leading to hardness enhancement. For misorientation angles smaller than 36.87°, plastic deformations are mainly caused by dislocation propagation, while for larger angles, it is mainly through atomic disordering mode.
MATERIALS & DESIGN
(2021)
Article
Materials Science, Multidisciplinary
Christian Haase, Markus Kuehbach, Luis A. Barrales-Mora, Su Leen Wong, Franz Roters, Dmitri A. Molodov, Guenter Gottstein
Article
Materials Science, Multidisciplinary
C. Miessen, M. Liesenjohann, L. A. Barrales-Mora, L. S. Shvindlerman, G. Gottstein
Article
Materials Science, Multidisciplinary
I. Basu, K. G. Pradeep, C. Miessen, L. A. Barrales-Mora, T. Al-Samman
Article
Materials Science, Multidisciplinary
M. Kuehbach, G. Gottstein, L. A. Barrales-Mora
Article
Nanoscience & Nanotechnology
Christian Haase, Tobias Ingendahl, Onur Guevenc, Markus Bambach, Wolfgang Bleck, Dmitri A. Molodov, Luis A. Barrales-Mora
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2016)
Article
Materials Science, Multidisciplinary
C. Miessen, N. Velinov, G. Gottstein, L. A. Barrales-Mora
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2017)
Article
Materials Science, Multidisciplinary
Mehran Afshar, Fengxin Mao, Haichun Jiang, Volker Mohles, Michael Schick, Klaus Hack, Sandra Korte-Kerzel, Luis A. Barrales-Mora
COMPUTATIONAL MATERIALS SCIENCE
(2019)
Article
Materials Science, Multidisciplinary
Christian Haase, Luis Antonio Barrales-Mora
Article
Materials Science, Multidisciplinary
Gashaw B. Bizana, Luis A. Barrales-Mora
Summary: The grain growth in nanosized polycrystalline Al was investigated using molecular dynamics. The study analyzed the volumetric growth rate of grains based on their size, topology, and mean curvature. It was discovered that grains with approximately 15 faces have zero mean curvature, and their volume remains unchanged. Additionally, the integral mean curvature of grains was found to be correlated with the difference in face numbers between grains and their neighbors. The study also observed discrepancies between theoretical predictions and measured growth rates, especially for grains with significant size differences and high face number differences.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Metallurgy & Metallurgical Engineering
Fengxin Mao, Moritz Weidt, Peter Staron, Sebastian Busch, Andreas Stark, Luis Barrales-Mora
Summary: In this study, the age-hardening behavior of two commercial Al-Si-Cu-Mg alloys was investigated using experimental and simulation methods. The characteristics of precipitates were summarized and a prediction model was developed.
INTERNATIONAL JOURNAL OF MATERIALS RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Surya N. Kumaran, Sudeep K. Sahoo, Christian Haase, Luis A. Barrales-Mora, Laszlo S. Toth
Summary: The evolution of microstructure, texture, and mechanical properties of an induction melted non-equiatomic high entropy alloy subjected to severe plastic deformation was investigated. Experimental analyses revealed the deformation of coarse-grained structure into nanocrystalline structure, the presence of nano-twins, and a significant increase in strength. Simulations reproduced the observed texture and estimated the fraction of twinning.
Article
Materials Science, Multidisciplinary
Jann-Erik Brandenburg, Luis A. Barrales-Mora, Sadahiro Tsurekawa, Dmitri A. Molodov
Summary: The migration behavior of grain boundaries with misorientations close to the & sigma;3 CSL orientation relationship in high purity Al bicrystals was investigated. It was found that the ability of some boundaries to move under capillary driving force depends on the initial boundary inclination. The measured migration activation enthalpy for one specific boundary was found to be the lowest among previous experiments in Al bicrystals of the same purity.
Article
Materials Science, Multidisciplinary
Gashaw B. Bizana, Luis A. Barrales-Mora
Summary: Classical theories assume a linear correlation between grain boundary curvature and velocity, but recent experimental observations suggest a more complex relationship in polycrystalline materials. Molecular dynamics simulations of nanosized polycrystalline Al annealing were used to determine the velocity and curvature of approximately 12,000 grain boundaries. The study revealed differences in kinetics behavior at the grain and grain-boundary levels, with a clear correlation between grain boundary curvature and migration direction. However, when considering all grain boundaries, the correlation between velocity and curvature was found to be low, indicating the complexity of grain boundary migration. Factors such as grain boundary character, defect distributions, and stress distribution between neighboring grains were found to influence grain boundary migration behavior.
Proceedings Paper
Materials Science, Multidisciplinary
D. A. Molodov, L. A. Barrales-Mora, J. E. Brandenburg
36TH RISO INTERNATIONAL SYMPOSIUM ON MATERIALS SCIENCE
(2015)
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.