Article
Materials Science, Multidisciplinary
Vignesh Vivekanandan, Peng Lin, Grethe Winther, Anter El-Azab
Summary: The continuum dislocation dynamics framework aims to capture the evolution of dislocation density and deformation of crystals under mechanical loading by solving transport equations for dislocations concurrently with crystal mechanics equations, incorporating dislocation reactions to improve predictability. The proposed formulation, which includes virtual dislocations to enforce dislocation line continuity, enables accurate enforcement of divergence free condition in numerical solutions, leading to highly accurate results in comparison with previous approaches.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2021)
Article
Materials Science, Multidisciplinary
Kolja Zoller, Patric Gruber, Michael Ziemann, Alexander Goertz, Peter Gumbsch, Katrin Schulz
Summary: Microwires have gained increasing interest for miniaturizing structural components. Understanding the deformation behavior of microwires is crucial for assessing their applicability and lifespan in specific components. This study analyzes the microstructure evolution of single crystalline gold microwires under torsion, specifically for high-symmetry crystal orientations (100), (110), and (111), using simulation and experimental results. The classification of slip systems can be predicted through theoretical considerations, and it is found that slip system activity, stress relaxation mechanism, and dislocation density depend on specific slip system groups.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Xi Luo, Michael Zaiser
Summary: Continuum dislocation dynamics (CDD) describes the evolution of curved and connected dislocation lines using density-like field variables, including the volume density of loops as an additional field. The curvature field evolution equation contains numerically inconvenient higher-order derivatives of the density fields, as dislocation curvature represents a spatial derivative of the discrete dislocation density tensor. We propose a simple approximation to express curvature in terms of density fields and demonstrate its application to a benchmark problem in Mg polycrystal deformation.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Balduin Katzer, Kolja Zoller, Daniel Weygand, Katrin Schulz
Summary: Plastic deformation of metals involves the formation and evolution of complex dislocation networks, which are crucial for the development of crystal plasticity models. This study demonstrates the transfer of knowledge from discrete dislocation dynamics simulations to continuum-based models through a physically based dislocation network evolution theory. The results show that the evolution of dislocation networks is influenced by crystal orientation and the activity of slip systems.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2022)
Article
Chemistry, Physical
Yanling Schneider, Dennis-Michael Rapp, Yifang Yang, Werner Wasserbaech, Siegfried Schmauder
Summary: This study numerically investigates the tensile deformation behavior of commercial polycrystalline Ag/17vol.%SnO2 composite materials and emphasizes micromechanical deformation behavior.
Article
Materials Science, Multidisciplinary
Maoyuan Jiang, Benoit Devincre
Summary: The influence of grain orientation on long-range internal stress associated with the accumulation of geometrically necessary dislocations (GNDs) during plastic deformation is numerically investigated. It is found that GNDs stored at grain boundaries (GBs) do not systematically generate a backstress within grains. Surprisingly, accumulation of GNDs at certain GB interfaces leads to the emergence of long-range anti-backstress, promoting dislocation dynamics and plastic strain within the grains. This discovery provides guidelines to improve the physical content of current crystal plasticity models.
COMPUTATIONAL MATERIALS SCIENCE
(2022)
Article
Materials Science, Multidisciplinary
Nilgoon Irani, Yaswanth Murugesan, Can Ayas, Lucia Nicola
Summary: Discrete dislocation plasticity is a modeling technique that treats plasticity as the collective motion of dislocations, with the core fields affecting edge dislocation interactions. Simulation results show that the influence of core fields is negligible compared to Volterra fields or external loads.
MECHANICS OF MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Ronan Madec, Luc Portelette, Bruno Michel, Jonathan Amodeo
Summary: The mechanical behavior of UO2 single crystal, especially the unexpected multi-slip observations, has been studied in this research. A multi-scale model based on composite slip is proposed, in which dislocation density can be transferred from primary slip systems to secondary systems under the effect of cross-slip. This approach accurately describes the anisotropic mechanical response of UO2 single crystal, providing new insights into the links between dislocation microstructures and mechanical properties. The composite slip mechanism appears to be a candidate for explaining unexpected plastic behaviors in complex materials with multiple slip modes, suggesting that slip activation may be more complex than in usual constitutive laws.
Article
Nuclear Science & Technology
Pandong Lin, Junfeng Nie, Meidan Liu
Summary: A multiscale crystal plasticity finite element model, incorporating molecular dynamics and crystal plasticity theory, is proposed to analyze the mechanical behavior of irradiated BCC metals. The numerical results agree well with experimental data, demonstrating the accuracy and feasibility of the model. The model captures irradiation hardening and provides a theoretical guide for selecting structural materials in nuclear plants.
NUCLEAR MATERIALS AND ENERGY
(2022)
Article
Chemistry, Physical
Alexander E. Doran, So Hirata
Summary: A scalable stochastic algorithm for evaluating fourth-order many-body perturbation (MP4) correction to energy has been proposed. The algorithm involves computer-generated diagrams and algebraic formulas expressed in terms of Green's functions, and is evaluated using Monte Carlo integration accelerated by redundant walker and control variate algorithms. The resulting MC-MP4 method is efficiently parallelized with significantly lower cost dependence compared to deterministic MP4 algorithm. It has been shown to accurately evaluate the energy of various molecules with a statistical uncertainty within a certain range after a large number of Monte Carlo steps.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Nanoscience & Nanotechnology
Qian Yin, Zhixun Wen, Jundong Wang, Yeda Lian, Guangxian Lu, Chengjiang Zhang, Zhufeng Yue
Summary: This study focuses on the stress and strain responses of a second-generation nickel-based superalloy at different temperatures and orientations. Microstructure and dislocation arrangements were observed to analyze the fracture failure modes and dislocation morphologies. A new hardening model and damage evolution law were proposed and successfully fitted the stress-strain response for different conditions.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Nanoscience & Nanotechnology
M. A. Ritzo, R. A. Lebensohn, L. Capolungo, S. R. Agnew
Summary: This study explores the role of dislocation climb in mediating plasticity in a Mg alloy at moderately elevated temperatures. The results reveal that dislocation climb is important over a wide range of temperatures and strain rates, and provides an explanation for various observations.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Daijun Hu, Nicolo Grilli, Wentao Yan
Summary: A temperature dependent continuum dislocation dynamics (CDD) model is developed and fully coupled with a crystal plasticity solver for investigating the formation and stability of dislocation structures in solid solution materials. The dynamics of dislocation structure formation at different positions during laser melting process and the effect of cyclic thermal stress during multi-layer fabrication are revealed using a multiscale modeling approach.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Article
Engineering, Mechanical
F. Bahrami, M. Hammad, M. Fivel, B. Huet, C. D'Haese, L. Ding, B. Nysten, H. Idrissi, J. P. Raskin, T. Pardoen
Summary: Graphene reinforcement has been studied for its impact on the mechanical properties of metals, showing earlier and shorter plastic indentation responses compared to systems without graphene. Atomic force microscopy reveals smoother pile-ups with graphene, while transmission electron microscopy shows more diffuse and homogeneous dislocation activity in the presence of graphene. The collective dislocation mechanisms are dominantly controlled by the strong back stress caused by the graphene barrier.
INTERNATIONAL JOURNAL OF PLASTICITY
(2021)
Article
Engineering, Mechanical
Yinan Cui, Tao Wang, Shichao Luo, Zhangtao Li, Zhijie Li
Summary: Understanding the deformation mechanism of materials at extremely high strain rates is crucial. In this study, a discrete-continuous model coupling three-dimensional discrete dislocation elastodynamics with the finite element method was developed, successfully reproducing the fully-resolved elastodynamic field of non-uniformly moving dislocations and revealing intriguing features of high-speed dislocations. This work provides an exciting opportunity to comprehend the collective behavior of high-speed dislocations under complex shock loading conditions.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Review
Chemistry, Multidisciplinary
Kevin S. Zhang, Ambika Nadkarni, Rajorshi Paul, Adrian M. Martin, Sindy K. Y. Tang
Summary: Microscale surgery has made significant advances in fundamental biology and engineering biological systems, but manual operations are labor-intensive and lack reproducibility. Microfluidics provides a powerful technology to control and manipulate cells and multicellular systems at the micro- and nanoscale with high precision. This review summarizes the physical and chemical mechanisms, design principles, applications, and implementations of microscale surgery in microfluidic systems. Existing challenges and opportunities are highlighted throughout the review.
Article
Chemistry, Physical
Haitao D. Deng, Hongbo Zhao, Norman Jin, Lauren Hughes, Benjamin H. Savitzky, Colin Ophus, Dimitrios Fraggedakis, Andras Borbely, Young-Sang Yu, Eder G. Lomeli, Rui Yan, Jueyi Liu, David A. Shapiro, Wei Cai, Martin Z. Bazant, Andrew M. Minor, William C. Chueh
Summary: This study developed a generalizable, physically constrained image-learning framework to learn the chemo-mechanical constitutive law from correlative microscopy images at the nanoscale. By applying this framework to LiXFePO4 battery positive electrode material, the researchers discovered the composition-eigenstrain relation and validated Vegard's law at the nanoscale. The study also visualized the residual strain field and identified heterogeneities arising from misfit dislocations.
Article
Chemistry, Physical
Allen P. Liu, Eric A. Appel, Paul D. Ashby, Brendon M. Baker, Elisa Franco, Luo Gu, Karmella Haynes, Neel S. Joshi, April M. Kloxin, Paul H. J. Kouwer, Jeetain Mittal, Leonardo Morsut, Vincent Noireaux, Sapun Parekh, Rebecca Schulman, Sindy K. Y. Tang, Megan T. Valentine, Sebastian L. Vega, Wilfried Weber, Nicholas Stephanopoulos, Ovijit Chaudhuri
Summary: Recent advancements in synthetic biology and biomaterials have provided exciting tools for creating new materials and extending the application of synthetic biology. Despite their transformative potential, these fields have mostly progressed separately. This Perspective reviews recent key advances and presents a roadmap for collaboration between the two communities, emphasizing the near-term applications in developing hierarchically structured biomaterials.
Article
Engineering, Manufacturing
Ottman A. Tertuliano, Philip J. DePond, David Doan, Manyalibo J. Matthews, X. Wendy Gu, Wei Cai, Adrian J. Lew
Summary: Laser powder bed fusion (LPBF) of pure copper for thermal and electrical applications is limited by low near-infrared absorptivity and high thermal diffusivity. This study investigates the effect of nanoparticle additives on absorptivity and melting behavior during LPBF. Using an in situ calorimetry system, decorated copper substrates with three nanoparticle systems (CuS, TiB2, multilayer graphene flakes) demonstrated enhanced absorptivity compared to pure copper. Graphene nanoflakes resulted in the highest improved absorption due to their stability at high laser scanning powers. The work also showed an improvement in relative density of the copper-graphene powder prints compared to as-purchased copper powder prints.
ADDITIVE MANUFACTURING
(2022)
Article
Materials Science, Multidisciplinary
Rasool Ahmad, Wei Cai
Summary: This article proposes a Boltzmann generator framework based on the normalizing flow model to generate equilibrium atomic configurations and determine free energy. The loss function is constructed from a statistical mechanical perspective, and the training is carried out in an unsupervised manner. The results show that the normalizing flow method is in good agreement with traditional free energy methods.
MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING
(2022)
Article
Physics, Multidisciplinary
Maurice de Koning, Wei Cai, Claudio Cazorla, Jordi Boronat
Summary: The mass transport properties along dislocation cores in hcp 4He are studied using a fully correlated quantum simulation approach and the PIGS method. The results show that the defective 4He systems have a negligible Bose-Einstein condensate fraction, indicating the absence of intrinsic superfluidity in dislocation cores. This challenges the interpretation of the mass-flux-experiment observations and calls for further experimental investigation.
PHYSICAL REVIEW LETTERS
(2023)
Article
Chemistry, Physical
Oleg A. Kuznetsov, Shaswat Mohanty, Elena Pigos, Gugang Chen, Wei Cai, Avetik R. Harutyunyan
Summary: This study develops self-standing composite electrodes for Li-ion batteries without electrochemically inactive metal current collectors, additives, and binders, increasing energy density and enabling online self-monitoring through the intrinsic piezoresistance of the single-wall carbon nanotube (SWNT) network. The proposed solution-free battery fabrication technology eliminates environmentally harmful components, enabling simple mechanical separation for recycling.
ENERGY STORAGE MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Sh. Akhondzadeh, Minju Kang, Ryan B. Sills, K. T. Ramesh, Wei Cai
Summary: A long-standing challenge in computational materials science is to establish a quantitative connection between macroscopic properties of plastic deformation and microscopic mechanisms of dislocations in crystalline materials. This study provides direct comparisons between stress-strain curves obtained from miniaturized bar experiments and those from discrete dislocation dynamics (DDD) simulations. The DDD simulations show good agreement with experimental results, but the required dislocation mobility values are significantly lower than expected. Cross-slip of screw dislocations is also found to be necessary to capture the experimental stress-strain behavior.
Article
Materials Science, Multidisciplinary
Rasool Ahmad, Mingliang Liu, Michael Ortiz, Tapan Mukerji, Wei Cai
Summary: This study focuses on calculating the homogenized elastic properties of rocks using 3D micro-CT scanned images. To solve the problem of large micro-CT images, a hierarchical homogenization method is proposed, where the image is divided into smaller subimages. The subimages are individually homogenized and then assembled to find the final homogenized elastic constant. The error in the homogenized constant follows a power law scaling with respect to the subimage size, and this scaling is used for better approximation of large heterogeneous microstructures.
JOURNAL OF THE MECHANICS AND PHYSICS OF SOLIDS
(2023)
Editorial Material
Chemistry, Physical
Vasily Bulatov, Wei Cai
Summary: The in situ electron microscopy study provides important insights into the enhanced dislocation mobility in iron and contributes to the ongoing debate on hydrogen embrittlement mechanisms.
Article
Geochemistry & Geophysics
Mingliang Liu, Rasool Ahmad, Wei Cai, Tapan Mukerji
Summary: Digital rock physics combines tomographic imaging techniques with numerical simulations to estimate effective rock properties. To address the computational challenge of large sample sizes, a hierarchical homogenization method with a data-driven surrogate model based on convolutional neural networks is proposed. The method reduces computational time and memory demand compared to conventional algorithms.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Multidisciplinary Sciences
Yifan Wang, Wei Cai
Summary: This study reveals the microscopic mechanisms of cross-slip of screw dislocations in crystalline solids using molecular dynamics simulation and identifies the influence of anharmonic effects. This finding contributes to a better understanding of stress-driven thermally activated processes in solids.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Materials Science, Multidisciplinary
Siying Peng, Yanming Wang, Michael Braun, Yikai Yin, Andrew C. Meng, Wanliang Tan, Balreen Saini, Kayla Severson, Ann F. Marshall, Katherine Sytwu, John D. Baniecki, Jennifer Dionne, Wei Cai, Paul C. McIntyre
Summary: Halide ion phase separation in CsPbIxBr3-x perovskite single crystals driven by light is investigated using in situ scanning transmission electron microscopy and cathodoluminescence at cryogenic temperatures. The observations and phase field modeling reveal a spinodal decomposition mechanism with non-linear growth of composition fluctuation and characteristic length scale over time. These findings provide microscopic insights for further engineering mixed-halide perovskites, allowing for stability improvements and intentional programming of halide ion composition, leading to a wide range of applications.
Article
Materials Science, Multidisciplinary
Jianan Chen, Chang Liu, Yifan Wang, Wangwang Ding, Qiying Tao, Gang Chen, Wei Cai, Mingli Qin, Xuanhui Qu
Summary: The study presents a method to overcome the strength-ductility trade-off by incorporating nanoscale deformable precipitates. An alloy with copiously and semi-coherently dispersed nanoscale zirconia precipitates was successfully designed and fabricated. The alloy exhibited exceptional tensile properties, achieving a record of strength and ductility combination for alloys fabricated by additive manufacturing.
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
(2024)
Article
Biochemical Research Methods
Nicolas Castano, Sungu Kim, Adrian M. Martin, Stephen J. Galli, Kari C. Nadeau, Sindy K. Y. Tang
Summary: In this study, an integrated basophil isolation device (i-BID) was developed using microfluidics for rapid and high-purity separation of basophils from 100 μL of whole blood. The device includes a magnetic separation module that effectively captures non-basophils while preventing clogging. The i-BID achieved an average purity of 93.9% +/- 3.6% and a recovery rate of 95.6% +/- 3.4%, without causing degradation or unintentional activation of basophils. This research has important implications for basophil-based diagnostics in allergic disorders and other diseases.
