Article
Chemistry, Multidisciplinary
Mingguang Yao, Fangren Shen, Dezhou Guo, Hua Zhang, Chunguang Zhai, Yuchen Shang, Jiajun Dong, Yuanlong Zhao, Zhaodong Liu, Zhipeng Li, Haixin Li, Hongdong Li, Qi An, Bingbing Liu
Summary: Introducing nanostructures into diamonds can synthesize superhard materials, but grain boundary effects become crucial yet complicated in nanopolycrystalline diamond (NPD), making it challenging to tailor nanostructures. This study demonstrates a strengthening strategy for sintered NPD by introducing thin amorphous grain boundary (AGB) using atomistic simulations and experiments. The sintered NPD with thin AGB shows significant hardness and fracture toughness enhancement, exceeding that of single crystal diamonds. This study suggests that grain boundary modulation provides a promising approach for designing high-performance superhard materials.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Zheng Gao, Chongqian Leng, Hongquan Zhao, Xingzhan Wei, Haofei Shi, Zeyun Xiao
Summary: This review provides an overview of the electrical properties of grain boundaries in polycrystalline optoelectronic materials and discusses the factors influencing the electrical behaviors of grain boundaries. It also explores how modifying the electrical behaviors of grain boundaries can enhance the performance of optoelectronic devices.
ADVANCED MATERIALS
(2023)
Article
Physics, Applied
Huicong Chen, Jun Song
Summary: This study presents a comprehensive investigation of solute segregation at twin boundaries in Mg using density functional theory. The preferential segregation sites and energies were identified for 56 solute elements. A two-factor model considering both mechanical and chemical effects was proposed and showed good agreement with the calculations. The results provide insights into the solute segregation behavior and its impact on the strength of twin boundaries, which is important for the development of high-performance Mg alloys.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Engineering, Mechanical
Jinliang Du, Jie Li, Yunli Feng, Ying Li, Fucheng Zhang
Summary: In order to improve the strength and plasticity of structural materials, various strengthening mechanisms are introduced. In this study, a deep learning network structure based on the residual algorithm was optimized using transfer learning data to establish a yield strength prediction model for polycrystalline metallic materials. A medium carbon steel heterostructure design strategy was proposed and successfully applied to prepare medium-carbon heterostructure materials with mixed strengthening mechanisms. The MHSM showed excellent comprehensive mechanical properties.
INTERNATIONAL JOURNAL OF PLASTICITY
(2023)
Article
Materials Science, Ceramics
Yidi Shen, Moon Young Yang, William A. Goddard, Qi An
Summary: The study focuses on using reactive molecular dynamics simulations to investigate the mechanical properties of boron carbide under hypervelocity impact, and found that doping silicon into the grain boundary significantly enhances both shear strength and stress threshold in the material.
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
(2022)
Article
Chemistry, Multidisciplinary
Elida I. de Obaldia, Jesus J. Alcantar-Pena, Frederick P. Wittel, Jean Francois Veyan, Salvador Gallardo-Hernadez, Yury Koudriavtsev, Dainet Berman-Mendoza, Orlando Auciello
Summary: This paper investigates the effect of hydrogen atom insertion into the grain boundaries of polycrystalline diamond films, focusing on the H atom concentration and its impact on the properties. The study suggests a simple model where two dangling bonds per unit cell of C atoms serve as the site of hydrogen incorporation. The experiment results show that the concentration of H atoms at the grain boundaries is consistent regardless of grain size. Conductive atomic force microscopy and ultraviolet photoelectron spectroscopy techniques were used to observe the electrical behavior and metallic properties of the films.
APPLIED SCIENCES-BASEL
(2021)
Article
Materials Science, Multidisciplinary
Dasheng Wei, Qinan Han, Lei Cai, Xuegang Min, Zonghan Xie, Feng Fang
Summary: A study on the production of pure iron wires through a two-step process of torsion and cold drawing showed an increase in Vickers hardness, changing grain structure, and enhanced tensile strength and elongation to failure, resulting in a desirable combination of high strength and ductility.
MATERIALS CHARACTERIZATION
(2021)
Article
Physics, Applied
Han Wang, Julian J. Rimoli, Penghui Cao
Summary: By using atomistic simulations, we investigated a range of nanotwinned materials with different stacking fault energies (SFEs) to understand the limit of twin boundary (TB) strengthening. In contrast to Cu and Al, nanotwinned materials with ultra-low SFEs (Co, NiCoCr, and NiCoCrFeMn) exhibited continuous strengthening down to a twin thickness of 0.63 nm. Our study revealed that even at the nanometer scale, hard dislocation modes persisted while the soft dislocation mode, which caused detwinning in Cu and Al, resulted in phase transformation and lamellar structure formation in Co, NiCoCr, and NiCoCrFeMn. This enhanced understanding of dislocation mechanisms in nanotwinned materials showcases the potential for controlling mechanical behavior and ultimate strength through tunable composition and SFE, particularly in multi-principal element alloys.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Chongze Hu, Douglas L. Medlin, Remi Dingreville
Summary: Twin boundaries play a crucial role in nanocrystalline metals, and an unusual segregation phenomenon at gold-doped platinum twin boundaries is mediated by the presence of disconnections, leading to an unexpected structural transition at the atomic scale induced by faulted disconnections.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Rolf Schaarschuch, Carl-Georg Oertel, Aurimas Pukenas, Shuaian Zhou, Guanghui Cao, Jens Freudenberger, Weimin Gan, Emad Maawad, Robert Chulist, Werner Skrotzki
Summary: The B2-type intermetallic compounds CoZr and Co39Ni11Zr50 exhibit different ductility at low temperatures, which may be related to their metallic character and slip mechanisms, providing insights for finding other ductile intermetallic systems.
Article
Nanoscience & Nanotechnology
Megan J. McCarthy, Timothy J. Rupert
Summary: This study investigates the migration behavior of a faceted Sigma 11 boundary in Cu doped with Ag atoms, revealing that solute atoms segregate to a facet with more free volume and greatly reduce boundary velocity in one migration direction. However, a directionally-dependent motion mechanism can escape solute pinning and speed up migration in the other direction, uncovering a new mechanism of chemically-induced anisotropy in grain boundary mobility.
SCRIPTA MATERIALIA
(2021)
Review
Chemistry, Multidisciplinary
Liu Yang, Yanyan Wang, Xu Wang, Shareen Shafique, Fei Zheng, Like Huang, Xiaohui Liu, Jing Zhang, Yuejin Zhu, Chuanxiao Xiao, Ziyang Hu
Summary: This review focuses on the application of atomic force microscopy (AFM)-based scanning probing techniques in investigating the local properties of polycrystalline photovoltaic materials. By studying the optoelectronic heterogeneities at grain interiors (GIs) and grain boundaries (GBs), it is possible to understand their critical roles in device performance and guide optimization. The potential of these AFM-based techniques in developing next-generation photovoltaics and optoelectronics is also discussed.
Review
Materials Science, Multidisciplinary
Naqash Ali, Liqiang Zhang, Dongming Liu, Hongwei Zhou, Kiran Sanaullah, Chaojie Zhang, Jianhua Chu, Yi Nian, Jinjun Cheng
Summary: High entropy alloys (HEAs) have emerged as a potential candidate for industrial applications due to their excellent mechanical properties at various temperatures. However, the trade-off between strength and ductility in HEAs requires modifications in conventional strengthening mechanisms such as adjusting stacking fault energy and promoting twin formation and phase transformation.
MATERIALS TODAY COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
Chaoqun Dang, Weitong Lin, Fanling Meng, Hongti Zhang, Sufeng Fan, Xiaocui Li, Ke Cao, Haokun Yang, Wenzhao Zhou, Zhengjie Fan, Ji-jung Kai, Yang Lu
Summary: This study introduces a facile strategy to enhance the ductility and yield strength of tungsten microcomponents, demonstrating potential applications in micro/nanoscale mechanical, electronic, and energy systems.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Multidisciplinary
Mingyu Wu, Wenting Lv, Yujuan Zhang, Yu Yang, Zhihang Wang, Kaikai Qiu, Yaxian Shi, Bo Zhao, Changchun Ge
Summary: We systematically studied the solution and aggregation behavior of Potassium (K) in the symmetrical tilt Tungsten (W) grain boundary (GB) Sigma 5(310)/[001] through first-principles simulations. The lowest-energy substitutional sites are the nearest neighbor sites of GB (V1) in the W-GB, instead of the GB sites themselves, which can be understood by the charge redistribution between the K and W atoms. Interestingly, our simulations show that segregation of multiple K atoms in W GB will form a cluster structure around the GB, which is well consistent with previous experimental reports. Electronic analysis reveals that previously trapped K atoms adjust the electronic densities around them to be more suitable for trapping more K atoms. Due to the greater binding energy of K-K over W-W at the GB, incorporation of K atoms leads to a slight increase in the fracture energy of the GB structure.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Review
Materials Science, Multidisciplinary
A. G. Sheinerman
Summary: This review surveys recent experiments, simulations, and theoretical models on plastic deformation and fracture processes in metal-matrix composites reinforced with graphene. The study focuses on strengthening mechanisms, strain hardening, and modeling processes. Various factors such as inclusion dimensions, interface characteristics, and buffer layers are examined, with a critical review of strengthening theories and discussion on contradictory results. Discussed are plastic deformation processes, self-healing, crack generation, and the influence of these processes on mechanical properties. The unique microstructure and strengthening mechanisms contribute to the excellent mechanical properties of metal/graphene composites.
CRITICAL REVIEWS IN SOLID STATE AND MATERIALS SCIENCES
(2022)
Article
Materials Science, Multidisciplinary
A. G. Sheinerman
Summary: A model has been proposed to explain the dependence of the strength of laminated metal/graphene composites on the lateral size of graphene platelets, suggesting that this is influenced by dislocations at metal/graphene interfaces and dislocation pinning by the edges of graphene platelets. It is also found that the specific energies of metal/graphene interfaces and lamella boundaries play a role in determining the strength of these composites, offering a potential way to control their strength by adjusting interface properties.
MECHANICS OF MATERIALS
(2021)
Article
Physics, Applied
A. G. Sheinerman, S. A. Krasnitskii
Summary: A model is proposed to analyze the effects of graphene agglomerates on the porosity, hardness, and fracture toughness of ceramic composites. The model suggests that the formation of pores around graphene agglomerates explains the decrease in hardness and fracture toughness of composites with increasing graphene volume fraction. The results of the model are consistent with experimental data on Al2O3-WC-TiC composites reinforced with graphene sheets.
TECHNICAL PHYSICS LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Elijah Borodin, Andrey P. Jivkov, Alexander G. Sheinerman, Mikhail Yu Gutkin
Summary: Designing new ceramic materials with specific thermo-electrical and mechanical properties is crucial for engineering applications. Recent research has shown that incorporating reduced graphene oxide (rGO) in hard ceramic matrix can enhance electrical conductivity and fracture toughness of nano-structured ceramic composites. The properties of these composites depend on the fraction and distribution of rGO inclusions, and a discrete combinatorial strategy utilizing algebraic topology and modern graph theory can be applied to design nano-structured ceramics with a superior balance between conductivity and fracture resistance.
MATERIALS & DESIGN
(2021)
Article
Mechanics
K. N. Mikaelyan, A. G. Sheinerman
Summary: A model is proposed to explain the plastic deformation in metal-graphene nanocomposites, suggesting that the deformation occurs through the generation of dislocation loops. The model calculates critical stresses for the generation and bypass of secondary dislocation loops, indicating that the addition of graphene can increase the yield strength of metals.
INTERNATIONAL JOURNAL OF SOLIDS AND STRUCTURES
(2022)
Article
Engineering, Mechanical
Xiaotao Li, Alexander G. Sheinerman, Hao Yang, Zhenyu Zhu
Summary: This study models and analyzes the effects of crack bridging, crack-tip dislocation emission, and crack deflection on crack growth in the CrMnFeCoNi high entropy alloy. The findings suggest that nanobridges formed through plastic deformation have a significant inhibiting effect on crack growth, while crack deflection has a great shielding effect on the driving force for crack growth.
INTERNATIONAL JOURNAL OF PLASTICITY
(2022)
Article
Materials Science, Multidisciplinary
Xiaotao Li, Alexander G. Sheinerman, Zhenyu Zhu, Feng Zhao
Summary: The tension-compression asymmetry mechanisms of grain boundary sliding were studied through molecular dynamics simulations. The results indicate that compressive stress inhibits grain boundary sliding, while tensile stress promotes it. The pressure-dependent behavior of grain boundary sliding is attributed to the tension-compression asymmetry of local shear events in grain boundaries, similar to shear banding in metallic glasses, as well as a novel strengthening mechanism of compression-induced grain boundary bending that increases the plastic flow stress.
Article
Mechanics
A. G. Sheinerman
Summary: This article proposes a model to describe the combined effects of crack bridging and ceramic/graphene interface strength on the fracture toughness of fully dense ceramic/graphene composites. By considering the situation where ceramic/graphene interfaces are weaker than the matrix grain boundaries, the model calculates the effects of graphene content and interface strength on the fracture toughness of composites using fracture mechanics combined with percolation theory. The calculations reveal the transition from toughening to fracture toughness reduction due to crack percolation over ceramic/graphene interfaces, indicating that high toughness ceramic/graphene composites should have large graphene platelets and/or small grain size.
EUROPEAN JOURNAL OF MECHANICS A-SOLIDS
(2023)
Article
Materials Science, Multidisciplinary
Alexander G. Sheinerman
Summary: A theoretical 2D model is proposed to investigate the effect of grain boundary segregations on fracture toughness in nanocrystalline alloys. The model considers crack curvature, surface roughness, and deflection near the crack tip caused by the segregations. It is found that the fracture toughness can be increased by 30-35% if a moderate proportion of brittle segregations occupy a large fraction of grain boundaries.
Article
Materials Science, Multidisciplinary
A. G. Sheinerman
Summary: This article proposes a model to describe the strengthening of nanocrystalline metallic alloys due to inhomogeneous grain boundary segregations. The model uses spherical dilatational inclusions to simulate such segregations, and considers two modes of plastic deformation: grain boundary sliding and lattice dislocation slip. The calculations show that inhomogeneous segregations only moderately strengthen nanocrystalline alloys with the finest grains, while high strengthening is achieved in alloys with larger grain sizes deformed through lattice dislocation slip.
MATERIALS PHYSICS AND MECHANICS
(2022)
Article
Metallurgy & Metallurgical Engineering
A. G. Sheinerman
Summary: This review summarizes recent experiments, computer simulations, and theoretical modeling on the mechanical properties of metal matrix composites with graphene and carbon nanotubes. It discusses the strengthening mechanisms, simulation results of plastic deformation and strength properties, and the effects of inclusion size, interface characteristics, and nonuniform grain size distribution on the strength and plasticity of these composites.
PHYSICS OF METALS AND METALLOGRAPHY
(2022)
Article
Materials Science, Multidisciplinary
S. V. Bobylev, A. G. Sheinerman
Summary: Theoretical model explores the impact of grain size distribution in the metal matrix of metal-graphene composite on yield strength, highlighting the importance of reducing dispersion in grain size during composite synthesis.
MATERIALS PHYSICS AND MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
A. G. Sheinerman, S. A. Krasnitckii
Summary: The model proposed in this study illustrates the impact of grain boundary relaxation on the annealing-induced hardening in ultrafine-grained metals. The decrease in the number of grain boundary dislocation sources during annealing leads to an increase in strain hardening rate, ultimately resulting in higher ultimate strength of ultrafine-grained solids. The results from the model are consistent with experimental data.
MATERIALS PHYSICS AND MECHANICS
(2021)
Article
Materials Science, Multidisciplinary
A. G. Sheinerman
MATERIALS PHYSICS AND MECHANICS
(2020)
Article
Materials Science, Multidisciplinary
A. G. Sheinerman, M. Yu Gutkin
LETTERS ON MATERIALS
(2020)
