The novel core−shell SiC@CoCrFeNiMn high-entropy alloy(HEA)matrix composites(SiC@HEA)were successfully prepared via mechanical ball milling and vacuum hot-pressing sintering(VHPS).After sintering,the microstructure wa...The novel core−shell SiC@CoCrFeNiMn high-entropy alloy(HEA)matrix composites(SiC@HEA)were successfully prepared via mechanical ball milling and vacuum hot-pressing sintering(VHPS).After sintering,the microstructure was composed of FCC solid solution,Cr_(23)C_(6) carbide phases,and Mn_(2)SiO_(4) oxy-silicon phase.The relative density,hardness,tensile strength,and elongation of SiC@HEA composites with 1.0 wt.%SiC were 98.5%,HV 358.0,712.3 MPa,and 36.2%,respectively.The core−shell structure had a significant deflecting effect on the cracks.This effect allowed the composites to effectively maintain the excellent plasticity of the matrix.As a result,the core−shell SiC@HEA composites obtained superior strength and plasticity with multiple mechanisms.展开更多
Magnetic carbon-based composites are the most attractive candidates for electromagnetic(EM)absorption because they can terminate the propagation of surplus EM waves in space by interacting with both electric and magne...Magnetic carbon-based composites are the most attractive candidates for electromagnetic(EM)absorption because they can terminate the propagation of surplus EM waves in space by interacting with both electric and magnetic branches.Metal-organic frameworks(MOFs)have demonstrated their great potential as sacrificing precursors of magnetic metals/carbon composites,because they provide a good platform to achieve high dispersion of magnetic nanoparticles in carbon matrix.Nevertheless,the chemical composition and microstructure of these composites are always highly dependent on their precursors and cannot promise an optimal EM state favorable for EM absorption,which more or less discount the superiority of MOFs-derived strategy.It is hence of great importance to develop some accompanied methods that can regulate EM properties of MOFs-derived magnetic carbon-based composites e ectively.This review comprehensively introduces recent advancements on EM absorption enhancement in MOFs-derived magnetic carbon-based composites and some available strategies therein.In addition,some challenges and prospects are also proposed to indicate the pending issues on performance breakthrough and mechanism exploration in the related field.展开更多
This paper presents a de-novo computational design method driven by deep reinforcement learning to achieve reliable predictions and optimum properties for periodic microstructures.With recent developments in 3-D print...This paper presents a de-novo computational design method driven by deep reinforcement learning to achieve reliable predictions and optimum properties for periodic microstructures.With recent developments in 3-D printing,microstructures can have complex geometries and material phases fabricated to achieve targeted mechanical performance.These material property enhancements are promising in improving the mechanical,thermal,and dynamic performance in multiple engineering systems,ranging from energy harvesting applications to spacecraft components.The study investigates a novel and efficient computational framework that integrates deep reinforcement learning algorithms into finite element-based material simulations to quantitatively model and design 3-D printed periodic microstructures.These algorithms focus on improving the mechanical and thermal performance of engineering components by optimizing a microstructural architecture to meet different design requirements.Additionally,the machine learning solutions demonstrated equivalent results to the physics-based simulations while significantly improving the computational time efficiency.The outcomes of the project show promise to the automation of the design and manufacturing of microstructures to enable their fabrication in large quantities with the utilization of the 3-D printing technology.展开更多
A micromechanics analysis on the possibility of designing a two-phase pseudoelastic composite is made for the case where ductile transformable shape mem- ory alloy plastic particles are imbedded coherently in an elast...A micromechanics analysis on the possibility of designing a two-phase pseudoelastic composite is made for the case where ductile transformable shape mem- ory alloy plastic particles are imbedded coherently in an elastic matrix. It is demon- strated that a pseudoelastic stress-strain loop in a macroscopic loading-unloading cy- cle can be obtained by microscopically stress induced forward and reverse martensitic transformations in the SMA particles. The relation between the macroscopic stress- strain response and the material parameters of the constituents of this composite is quantified through the micromechanics calculations, which reveals that the best duc- tility and thus the greatest energy absorption capacity of this novel microstructure can be obtained by the optimum material design.展开更多
Based on a level set model and the homogenization theory, an optimization al- gorithm for ?nding the optimal con?guration of the microstructure with speci?ed properties is proposed, which extends current resea...Based on a level set model and the homogenization theory, an optimization al- gorithm for ?nding the optimal con?guration of the microstructure with speci?ed properties is proposed, which extends current research on the level set method for structure topology opti- mization. The method proposed employs a level set model to implicitly describe the material interfaces of the microstructure and a Hamilton-Jacobi equation to continuously evolve the ma- terial interfaces until an optimal design is achieved. Meanwhile, the moving velocities of level set are obtained by conducting sensitivity analysis and gradient projection. Besides, how to handle the violated constraints is also discussed in the level set method for topological optimization, and a return-mapping algorithm is constructed. Numerical examples show that the method exhibits outstanding ?exibility of handling topological changes and ?delity of material interface represen- tation as compared with other conventional methods in literatures.展开更多
The generation of multiphase porous electrode microstructures with optimum morphological and transport properties is essential in the design of improved electrochemical energy storage devices,such as lithium-ion batte...The generation of multiphase porous electrode microstructures with optimum morphological and transport properties is essential in the design of improved electrochemical energy storage devices,such as lithium-ion batteries.Electrode characteristics directly influence battery performance by acting as the main sites where the electrochemical reactions coupled with transport processes occur.This work presents a generation-optimisation closed-loop algorithm for the design of microstructures with tailored properties.A deep convolutional Generative Adversarial Network is used as a deep kernel and employed to generate synthetic three-phase three-dimensional images of a porous lithium-ion battery cathode material.A Gaussian Process Regression uses the latent space of the generator and serves as a surrogate model to correlate the morphological and transport properties of the synthetic microstructures.This surrogate model is integrated into a deep kernel Bayesian optimisation framework,which optimises cathode properties as a function of the latent space of the generator.A set of objective functions were defined to perform the maximisation of morphological properties(e.g.,volume fraction,specific surface area)and transport properties(relative diffusivity).We demonstrate the ability to perform simultaneous maximisation of correlated properties(specific surface area and relative diffusivity),as well as constrained optimisation of these properties.This is the maximisation of morphological or transport properties constrained by constant values of the volume fraction of the phase of interest.Visualising the optimised latent space reveals its correlation with morphological properties,enabling the fast generation of visually realistic microstructures with customised properties.展开更多
Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Opt...Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Optimization(FPTO)method to achieve smooth topology design.The objective is to optimize the periodic microstructure to maximize the properties of specific materials,such as bulk modulus and shear modulus,or to achieve negative Poisson's ratio.Linear material interpolation is used to eliminate the nonlinear challenges and design dependence caused by material penalty.Furthermore,the three-field density representation technique is applied to augment length scales and solid/void characteristics.Through systematic analysis and numerical simulations,the impacts of various initial designs and optimization parameters on the optimization outcomes are investigated.The results demonstrate that the optimized periodic microstructures exhibit extreme performance with clear boundaries.The identification of appropriate optimization parameters is crucial for enhancing the extreme mechanical properties of material microstructures.It can provide valuable guidance for aerospace component design involving material microstructures and metamaterials.展开更多
Sensitivity analysis and topology optimization of microstructures using strain energy-based method is presented. Compared with homogenization method, the strain energy-based method has advantages of higher computing e...Sensitivity analysis and topology optimization of microstructures using strain energy-based method is presented. Compared with homogenization method, the strain energy-based method has advantages of higher computing efficiency and simplified programming. Both the dual convex programming method and perimeter constraint scheme are used to optimize the 2D and 3D microstructures. Numerical results indicate that the strain energy-based method has the same effectiveness as that of homogenization method for orthotropic materials.展开更多
Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides...Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides distinguish themselves from the mains cathode materials of SIBs owing to their advantages such as high specific capacity,simple synthesis route,and environmental benignity.However,the commercial development of the layered oxides is limited by sluggish kinetics,complex phase transition and poor air stability.Based on the research ideas from macro-to micro-scale,this review systematically summarizes the current optimization strategies of sodium-ion layered oxide cathodes(SLOC)from different dimensions:microstructure design,local chemistry regulation and structural unit construction.In the dimension of microstructure design,the various structures such as the microspheres,nanoplates,nanowires and exposed active facets are prepared to improve the slow kinetics and electrochemical performance.Besides,from the view of local chemistry regulation by chemical element substitution,the intrinsic electron/ion properties of SLOC have been enhanced to strengthen the structural stability.Furthermore,the optimization idea of endeavors to regulate the physical and chemical properties of cathode materials essentially is put forward from the dimension of structural unit construction.The opinions and strategies proposed in this review will provide some inspirations for the design of new SLOC in the future.展开更多
A concept of microstructure design for materials or materials microstructure engineering is proposed. The argument was suggested based on literature review and. some our new research work on second phase strengthening...A concept of microstructure design for materials or materials microstructure engineering is proposed. The argument was suggested based on literature review and. some our new research work on second phase strengthening mechanisms and mechanical property modeling of a particulate reinforced metal matrix composite. Due to development of computer technology, it is possible now for us to establish the relationship between microstructures and properties systematically and quantitatively by analytical and numerical modeling in the research scope of computerization materials. Discussions and examples on intellectual optimization of microstructure are presented on two aspects: grain boundary engineering and optimal geometry of particulate reinforcements in two-phase materials.展开更多
Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction...Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction interfaces.Among the various flexible sensor types,those with microstructure designs are considered promising for strain sensing due to their simple structure,high sensitivity,extensive operational range,rapid response time,and robust stability.This review provides a concise overview of recent advancements in flexible piezoresistive sensors based on microstructure design for enhanced strain sensing performance,including the impact of microstructure on sensing mechanisms,classification of microstructure designs,fabrication methods,and practical applications.Initially,this review delves into the analysis of piezoresistive sensor sensing mechanisms and performance parameters,exploring the relationship between microstructure design and performance enhancement.Subsequently,an in-depth discussion is presented,focusing on the primary themes of microstructure design classification,process selection,performance characteristics,and specific applications.This review employs mathematical modeling and hierarchical analysis to emphasize the directionality of different microstructures on performance enhancement and to highlight the performance advantages and applicable features of various microstructure types.In conclusion,this review examines the multifunctionality of flexible piezoresistive sensors based on microstructure design and addresses the challenges that still need to be overcome and improved,such as achieving a wide range of stretchability,high sensitivity,and robust stability.This review summarizes the research directions for enhancing sensing performance through microstructure design,aiming to assist in the advancement of flexible piezoresistive sensors.展开更多
Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numeri...Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numerical approach.However,the material assumptions for past computational human femur simulations were mainly homogeneous.Thus,this study aimed to design and analyze scaffolds for reconstructing the distal femur defect using a patient-specific finite element modeling technique.A three-dimensional finite element model of the human femur with accurate geometry and material distribution was developed using the finite element method and material mapping technique.An intact femur and a distal femur defect model treated with nine microstructure scaffolds and two solid scaffolds were investigated and compared under a single-leg stance loading.The results showed that the metal solid scaffold design could provide the most stable fixation for reconstructing the distal femur defect.However,the fixation stability was affected by various microstructure designs and pillar diameters.A microstructure scaffold can be designed to satisfy all the biomechanical indexes,opening up future possibilities for more stable reconstructions.A three-dimensional finite element model of the femur with real bone geometry and bone material distribution can be developed,and this patient-specific femur model can be used for studying other femoral fractures or injuries,paving the way for more comprehensive research in the field.Besides,this patient-specific finite element modeling technique can also be applied to developing other human or animal bone models,expanding the scope of biomechanical research.展开更多
Magnesium-air(Mg-air)batteries have emerged as a promising sustainable energy storage technology,offering exceptional theoretical energy density,low cost,and environmental compatibility.Despite these advantages,their ...Magnesium-air(Mg-air)batteries have emerged as a promising sustainable energy storage technology,offering exceptional theoretical energy density,low cost,and environmental compatibility.Despite these advantages,their development remains largely confined to experimental phase.A critical barrier to commercialization is the poor corrosion resistance of the anode resulting in low anodic efficiency.This article presents a comprehensive review of strategies aimed at improving the utilization efficiency of Mg anodes,with a particular focus on addressing corrosion issues from a microstructural standpoint.Firstly,the principle of Mg-air batteries has been outlined and the corrosion behavior has been discussed.The review then delves into a variety of representative anode materials.Special attention is given to innovative material designs that mitigate the challenges typically encountered by Mg-air batteries.Finally,the paper provides an outlook on future research directions,identifying critical technological barriers and highlighting areas that warrant further investigation.By offering a detailed analysis of material structures,this article aims to contribute valuable insights for advancing the development of high-performance Mg-air batteries.展开更多
In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn_(4) and soft Zn phases.Precipitation...In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn_(4) and soft Zn phases.Precipitation and multi-modal grain structure are designed to toughen β-LiZn_(4) while strengthen Zn,resulting in high strength and high ductility for both the phases.Needle-like secondary Zn precipitates form in β-LiZn4,while fine-scale networks of string-like β-LiZn4 precipitates form in Zn with a tri-modal grain structure.As a result,near-eutectic Zn-0.48 Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling,a novel fabrication process to realize the microstructure design.The as-rolled alloy has yield strength(YS) of 246 MPa,the ultimate tensile strength(UTS) of 395 MPa and elongation to failure(EL) of 47 %.Immersion test in simulated body fluid(SBF) for 30 days reveals that Li-rich products form preferentially at initial stage,followed by Zn-rich products with prolonged time.Aqueous insoluble Li_(2) CO_(3) forms a protective passivation film on the alloy surface,which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five.Afterwards,the average corrosion rate increases slightly with decrease of Li2 CO_(3) content,which undulates around the clinical requirements on corrosion resistance(i.e.,20 μm/year) claimed for biodegradable metal stents.展开更多
The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain ...The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain direction onthe microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain directioncan modify microstructure of Ti-25Al-10～12Nb (at. pct) alloy during α_2→O-phase transformation effectively andfull laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along thedirection 30°away from the α_2 phase <1010> in magnitude equivalent to the stress-free transformation strain. Thesimulation also shows that not only the magnitude of applied strain but also the applied strain direction influencesthe O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.展开更多
Pentamode acoustic cloak is promising for underwater sound control due to its solid nature and broadband efficiency,however its realization is only limited to simple cylindrical shape.In this work,we established a set...Pentamode acoustic cloak is promising for underwater sound control due to its solid nature and broadband efficiency,however its realization is only limited to simple cylindrical shape.In this work,we established a set of techniques for the microstructure design of elliptical pentamode acoustic cloak based on truss lattice model,including the inverse design of unit cell and algorithms for latticed cloak assembly.The designed cloak was numerically validated by the well wave concealing performance.The work proves that more general pentamode acoustic wave devices beyond simple cylindrical geometry are theoretically feasible,and sheds light on more practical design for waterborne sound manipulation.展开更多
The influence of La_(2)O_(3)inclusion(0-3 wt%)on the micro structure,phase formation and mechanical properties of zirconia toughed alumina(ZTA)added with 5.0 wt%CeO_(2)was investigated.ZTA CeO_(2)composites were sinte...The influence of La_(2)O_(3)inclusion(0-3 wt%)on the micro structure,phase formation and mechanical properties of zirconia toughed alumina(ZTA)added with 5.0 wt%CeO_(2)was investigated.ZTA CeO_(2)composites were sintered at 1600℃for 4 h.The microstructure,phase formation,density,fracture toughness and hardness properties were characterised through FESEM,Microscopy Image Analysis Software and XRD diffractometer,Archimedes principle and Vickers indentation technique,respectively.The XRD,image processing and FESEM reveal the existence of LaAl_(11)O_(18).The addition of La_(2)O_(3)incites the sintering,microstructure refinement,densification of ZTA-CeO_(2)matrix and phase transformation.Hence,the hardness of ZTA-CeO_(2)ceramics is increased rapidly based on refinement of Al_(2)O_(3)grains,densification of ZTA-CeO_(2)composites and porosity reduction.It is observed that the fracture toughness is enhanced through in situ formation of elongated LaAl_(11)O_(18)grains.The addition of 0.7 wt%La_(2)O_(3)culminated in the achievement of the optimum findings for density(4.41 g/cm^(3)),porosity(0.46%),hardness(1792 HV)and fracture toughness(8.8 MPa·m^(1/2)).Nevertheless,excess La_(2)O_(3)is proven to be detrimental as it displays poor mechanical properties due to the poor compactness of numerous LaAl_(11)O_(18)grains,coarsening of Al_(2)O_(3)grains and decline in density.展开更多
LaCe-based sintered magnets with different microstructural features and distinct rare earth elemental distribution were designed by dual-alloy method.The sample prepared by fine LaCe-containing powder and coarse LaCe-...LaCe-based sintered magnets with different microstructural features and distinct rare earth elemental distribution were designed by dual-alloy method.The sample prepared by fine LaCe-containing powder and coarse LaCe-free powder possesses higher remanence(~13.41 kGs),whereas another sample prepared by fine LaCe-free powder and coarse LaCe-containing powder possesses higher coercivity(~5.67 kOe).Additionally,these samples are with the same nominal compositions and their elemental distribution features are obviously different in matrix grains respectively.Their remanence difference is mainly affected by the saturation magnetization difference caused by the distribution variation of the rare earth elements at the matrix phase.The coercivity difference is affected by the component of the grain boundary phase between the adjacent grains and the distribution variation of the rare earth elements at the matrix phase.These findings may provide a new prospect for the utilization of LaCe mischmetal in 2:14:1-type permanent magnets.展开更多
A series of CoCrFeNb_xNi（x values in molar ratio, x = 0, 0.25, 0.45, 0.5, 0.75, 1.0 and 1.2） high entropy alloys（HEAs） was prepared to investigate the alloying effect of Nb on the microstructures and mechanical pr...A series of CoCrFeNb_xNi（x values in molar ratio, x = 0, 0.25, 0.45, 0.5, 0.75, 1.0 and 1.2） high entropy alloys（HEAs） was prepared to investigate the alloying effect of Nb on the microstructures and mechanical properties. The results indicate that the prepared CoCrFeNb_xNi（x 〉 0） HEAs consist of a simple FCC solid solution phase and a Laves phase. The microstructures of the alloys change from an initial single-phase FCC solid solution structure（x = 0） to a hypoeutectic microstructure（x = 0.25）, then to a full eutectic microstructure（x = 0.45） and finally to a hypereutectic microstructure（0.5 〈 x 〈 1.2）. The compressive test results show that the Nb0.45（x = 0.45） alloy with a full eutectic microstructure possesses the highest compressive fracture strength of 2558 MPa and a fracture strain of 27.9%. The CoCrFeNi alloy exhibits an excellent compressive ductility, which can reach 50% height reduction without fracture. The Nb0.25 alloy with a hypoeutectic structure exhibits a larger plastic strain of 34.8%. With the increase of Nb content, increased hard/brittle Laves phase leads to a decrease of the plasticity and increases of the Vickers hardness and the wear resistance. The wear mass loss, width and depth of wear scar of the Nb1.2（x = 1.2） alloy with a hypereutectic structure are the lowest among all alloy systems, indicating that the wear resistance of the Nb1.2 alloy is the best one.展开更多
Unbalanced properties for both fine-grained gamma and coarse-grained lamellar microstructures typically produced in gamma alloys are described. Efforts for the improvements are reviewed along with some experimental re...Unbalanced properties for both fine-grained gamma and coarse-grained lamellar microstructures typically produced in gamma alloys are described. Efforts for the improvements are reviewed along with some experimental results. Empirical improvements have been made in cast alloys, which have led gamma alloys to a viable materials technology and to the development of various application areas for gas turbine engines as well as automotive engines. Efforts to understand fundamental and applied aspects leading to the improvements are assessed for wrought alloys. Optimization of microstructures through process control,innovative heat treatments, alloy chemistry modification and their combinations have progressed in the endeavor. Similar efforts have just begun for cast alloys where work on fundamental understanding has been lagging. Future directions are suggested for further improvements and predicted for the development of higher temperature/performance alloys.展开更多
基金supported by Key Laboratory of Infrared Imaging Materials and Detectors,Shanghai Institute of Technical Physics,Chinese Academy of Sciences(No.IIMDKFJJ-21-10)China Postdoctoral Science Foundation(No.2018T110993)。
文摘The novel core−shell SiC@CoCrFeNiMn high-entropy alloy(HEA)matrix composites(SiC@HEA)were successfully prepared via mechanical ball milling and vacuum hot-pressing sintering(VHPS).After sintering,the microstructure was composed of FCC solid solution,Cr_(23)C_(6) carbide phases,and Mn_(2)SiO_(4) oxy-silicon phase.The relative density,hardness,tensile strength,and elongation of SiC@HEA composites with 1.0 wt.%SiC were 98.5%,HV 358.0,712.3 MPa,and 36.2%,respectively.The core−shell structure had a significant deflecting effect on the cracks.This effect allowed the composites to effectively maintain the excellent plasticity of the matrix.As a result,the core−shell SiC@HEA composites obtained superior strength and plasticity with multiple mechanisms.
基金supported by the financial support from Natural Science Foundation of China(21776053 and 21676065)。
文摘Magnetic carbon-based composites are the most attractive candidates for electromagnetic(EM)absorption because they can terminate the propagation of surplus EM waves in space by interacting with both electric and magnetic branches.Metal-organic frameworks(MOFs)have demonstrated their great potential as sacrificing precursors of magnetic metals/carbon composites,because they provide a good platform to achieve high dispersion of magnetic nanoparticles in carbon matrix.Nevertheless,the chemical composition and microstructure of these composites are always highly dependent on their precursors and cannot promise an optimal EM state favorable for EM absorption,which more or less discount the superiority of MOFs-derived strategy.It is hence of great importance to develop some accompanied methods that can regulate EM properties of MOFs-derived magnetic carbon-based composites e ectively.This review comprehensively introduces recent advancements on EM absorption enhancement in MOFs-derived magnetic carbon-based composites and some available strategies therein.In addition,some challenges and prospects are also proposed to indicate the pending issues on performance breakthrough and mechanism exploration in the related field.
基金funded by the NASA Virginia Space Grant Consortium Grant(Project Title:“Deep Reinforcement Learning for De-Novo Computational Design of Meta-Materials”).
文摘This paper presents a de-novo computational design method driven by deep reinforcement learning to achieve reliable predictions and optimum properties for periodic microstructures.With recent developments in 3-D printing,microstructures can have complex geometries and material phases fabricated to achieve targeted mechanical performance.These material property enhancements are promising in improving the mechanical,thermal,and dynamic performance in multiple engineering systems,ranging from energy harvesting applications to spacecraft components.The study investigates a novel and efficient computational framework that integrates deep reinforcement learning algorithms into finite element-based material simulations to quantitatively model and design 3-D printed periodic microstructures.These algorithms focus on improving the mechanical and thermal performance of engineering components by optimizing a microstructural architecture to meet different design requirements.Additionally,the machine learning solutions demonstrated equivalent results to the physics-based simulations while significantly improving the computational time efficiency.The outcomes of the project show promise to the automation of the design and manufacturing of microstructures to enable their fabrication in large quantities with the utilization of the 3-D printing technology.
文摘A micromechanics analysis on the possibility of designing a two-phase pseudoelastic composite is made for the case where ductile transformable shape mem- ory alloy plastic particles are imbedded coherently in an elastic matrix. It is demon- strated that a pseudoelastic stress-strain loop in a macroscopic loading-unloading cy- cle can be obtained by microscopically stress induced forward and reverse martensitic transformations in the SMA particles. The relation between the macroscopic stress- strain response and the material parameters of the constituents of this composite is quantified through the micromechanics calculations, which reveals that the best duc- tility and thus the greatest energy absorption capacity of this novel microstructure can be obtained by the optimum material design.
基金Project supported by the National Natural Science Foundation of China (Nos. 59805001 and 10332010) and the KeyScience and Technology Research Project of Ministry of Education of China (No. 104060).
文摘Based on a level set model and the homogenization theory, an optimization al- gorithm for ?nding the optimal con?guration of the microstructure with speci?ed properties is proposed, which extends current research on the level set method for structure topology opti- mization. The method proposed employs a level set model to implicitly describe the material interfaces of the microstructure and a Hamilton-Jacobi equation to continuously evolve the ma- terial interfaces until an optimal design is achieved. Meanwhile, the moving velocities of level set are obtained by conducting sensitivity analysis and gradient projection. Besides, how to handle the violated constraints is also discussed in the level set method for topological optimization, and a return-mapping algorithm is constructed. Numerical examples show that the method exhibits outstanding ?exibility of handling topological changes and ?delity of material interface represen- tation as compared with other conventional methods in literatures.
文摘The generation of multiphase porous electrode microstructures with optimum morphological and transport properties is essential in the design of improved electrochemical energy storage devices,such as lithium-ion batteries.Electrode characteristics directly influence battery performance by acting as the main sites where the electrochemical reactions coupled with transport processes occur.This work presents a generation-optimisation closed-loop algorithm for the design of microstructures with tailored properties.A deep convolutional Generative Adversarial Network is used as a deep kernel and employed to generate synthetic three-phase three-dimensional images of a porous lithium-ion battery cathode material.A Gaussian Process Regression uses the latent space of the generator and serves as a surrogate model to correlate the morphological and transport properties of the synthetic microstructures.This surrogate model is integrated into a deep kernel Bayesian optimisation framework,which optimises cathode properties as a function of the latent space of the generator.A set of objective functions were defined to perform the maximisation of morphological properties(e.g.,volume fraction,specific surface area)and transport properties(relative diffusivity).We demonstrate the ability to perform simultaneous maximisation of correlated properties(specific surface area and relative diffusivity),as well as constrained optimisation of these properties.This is the maximisation of morphological or transport properties constrained by constant values of the volume fraction of the phase of interest.Visualising the optimised latent space reveals its correlation with morphological properties,enabling the fast generation of visually realistic microstructures with customised properties.
基金supported by the financial support from the National Natural Science Foundation of China(No.52172356)Hunan Provincial Natural Science Foundation of China(No.2022JJ10012)。
文摘Topology optimization stands as a pivotal technique in realizing periodic microstructure design.A novel approach is proposed,integrating the energy-based homogenization method with the Floating Projection Topology Optimization(FPTO)method to achieve smooth topology design.The objective is to optimize the periodic microstructure to maximize the properties of specific materials,such as bulk modulus and shear modulus,or to achieve negative Poisson's ratio.Linear material interpolation is used to eliminate the nonlinear challenges and design dependence caused by material penalty.Furthermore,the three-field density representation technique is applied to augment length scales and solid/void characteristics.Through systematic analysis and numerical simulations,the impacts of various initial designs and optimization parameters on the optimization outcomes are investigated.The results demonstrate that the optimized periodic microstructures exhibit extreme performance with clear boundaries.The identification of appropriate optimization parameters is crucial for enhancing the extreme mechanical properties of material microstructures.It can provide valuable guidance for aerospace component design involving material microstructures and metamaterials.
基金National Natural Science Foundation of China （90405016, 10676028） 973 Program （2006CB601205）+1 种基金 863 Project （2006AA04Z 122） Aeronautical Science Foundation （04B53080, 2006ZA 53006） and 111 Project （B07050）
文摘Sensitivity analysis and topology optimization of microstructures using strain energy-based method is presented. Compared with homogenization method, the strain energy-based method has advantages of higher computing efficiency and simplified programming. Both the dual convex programming method and perimeter constraint scheme are used to optimize the 2D and 3D microstructures. Numerical results indicate that the strain energy-based method has the same effectiveness as that of homogenization method for orthotropic materials.
基金supported by the National Natural Science Foundation of China(51971124,52171217)the State Key Laboratory of Electrical Insulation and Power Equipment,Xi’an Jiaotong University(EIPE22208)+5 种基金the National Postdoctoral Program for Innovative Talents(BX20200222)the China Postdoctoral Science Foundation(2020M682878)Zhejiang Natural Science Foundation(LQ23E020002)Wenzhou Natural Science Foundation(G20220019)Cooperation between industry and education project of Ministry of Education(220601318235513)National Natural Science Foundation of China(52202284)。
文摘Because of the low price and abundant reserves of sodium compared with lithium,the research of sodium-ion batteries(SIBs)in the field of large-scale energy storage has returned to the research spotlight.Layered oxides distinguish themselves from the mains cathode materials of SIBs owing to their advantages such as high specific capacity,simple synthesis route,and environmental benignity.However,the commercial development of the layered oxides is limited by sluggish kinetics,complex phase transition and poor air stability.Based on the research ideas from macro-to micro-scale,this review systematically summarizes the current optimization strategies of sodium-ion layered oxide cathodes(SLOC)from different dimensions:microstructure design,local chemistry regulation and structural unit construction.In the dimension of microstructure design,the various structures such as the microspheres,nanoplates,nanowires and exposed active facets are prepared to improve the slow kinetics and electrochemical performance.Besides,from the view of local chemistry regulation by chemical element substitution,the intrinsic electron/ion properties of SLOC have been enhanced to strengthen the structural stability.Furthermore,the optimization idea of endeavors to regulate the physical and chemical properties of cathode materials essentially is put forward from the dimension of structural unit construction.The opinions and strategies proposed in this review will provide some inspirations for the design of new SLOC in the future.
基金the National Natural Science Foundation of China for the financial support by the grant 50171018 and 59771015, and Education Ministry of China for an outstanding teacher research fund to this study. Some student work
文摘A concept of microstructure design for materials or materials microstructure engineering is proposed. The argument was suggested based on literature review and. some our new research work on second phase strengthening mechanisms and mechanical property modeling of a particulate reinforced metal matrix composite. Due to development of computer technology, it is possible now for us to establish the relationship between microstructures and properties systematically and quantitatively by analytical and numerical modeling in the research scope of computerization materials. Discussions and examples on intellectual optimization of microstructure are presented on two aspects: grain boundary engineering and optimal geometry of particulate reinforcements in two-phase materials.
基金supported by the National Natural Science Foundation of China(No.52204299)the Natural Science Foundation of Hunan Province(Nos.2022JJ40623 and 2022JJ30722)the Start-Up Funds for Outstanding Talents in Central South University(Nos.202045007 and 202044017).
文摘Flexible piezoresistive strain sensors have received significant attention due to their diverse applications in monitoring human activities and health,as well as in robotics,prosthetics,and human–computer interaction interfaces.Among the various flexible sensor types,those with microstructure designs are considered promising for strain sensing due to their simple structure,high sensitivity,extensive operational range,rapid response time,and robust stability.This review provides a concise overview of recent advancements in flexible piezoresistive sensors based on microstructure design for enhanced strain sensing performance,including the impact of microstructure on sensing mechanisms,classification of microstructure designs,fabrication methods,and practical applications.Initially,this review delves into the analysis of piezoresistive sensor sensing mechanisms and performance parameters,exploring the relationship between microstructure design and performance enhancement.Subsequently,an in-depth discussion is presented,focusing on the primary themes of microstructure design classification,process selection,performance characteristics,and specific applications.This review employs mathematical modeling and hierarchical analysis to emphasize the directionality of different microstructures on performance enhancement and to highlight the performance advantages and applicable features of various microstructure types.In conclusion,this review examines the multifunctionality of flexible piezoresistive sensors based on microstructure design and addresses the challenges that still need to be overcome and improved,such as achieving a wide range of stretchability,high sensitivity,and robust stability.This review summarizes the research directions for enhancing sensing performance through microstructure design,aiming to assist in the advancement of flexible piezoresistive sensors.
基金funded by the TaipeiMedical University-National Taiwan University of Science and Technology joint research program under Grant No.TMU-NTUST-109-09.
文摘Reconstruction of a traumatic distal femur defect remains a therapeutic challenge.Bone defect implants have been proposed to substitute the bone defect,and their biomechanical performances can be analyzed via a numerical approach.However,the material assumptions for past computational human femur simulations were mainly homogeneous.Thus,this study aimed to design and analyze scaffolds for reconstructing the distal femur defect using a patient-specific finite element modeling technique.A three-dimensional finite element model of the human femur with accurate geometry and material distribution was developed using the finite element method and material mapping technique.An intact femur and a distal femur defect model treated with nine microstructure scaffolds and two solid scaffolds were investigated and compared under a single-leg stance loading.The results showed that the metal solid scaffold design could provide the most stable fixation for reconstructing the distal femur defect.However,the fixation stability was affected by various microstructure designs and pillar diameters.A microstructure scaffold can be designed to satisfy all the biomechanical indexes,opening up future possibilities for more stable reconstructions.A three-dimensional finite element model of the femur with real bone geometry and bone material distribution can be developed,and this patient-specific femur model can be used for studying other femoral fractures or injuries,paving the way for more comprehensive research in the field.Besides,this patient-specific finite element modeling technique can also be applied to developing other human or animal bone models,expanding the scope of biomechanical research.
基金financially supported by the National Natural Science Foundation of China(52274295)Hebei Province Science and Technology Research and Development Platform Special Innovation Capability Enhancement Plan Project(24464402D)+3 种基金the Fundamental Research Funds for the Central Universities(N2423051,N2423005)the Science and Technology Project of Hebei Education Department(QN2024238)The Basic Research Program Project of Shijiazhuang City for Universities Stationed in Hebei Province(241790937A)2025 Hebei Provincial Post-graduate Student Innovation Ability Training Funding Project(CXZZBS2025202,CXZZSS2025157)。
文摘Magnesium-air(Mg-air)batteries have emerged as a promising sustainable energy storage technology,offering exceptional theoretical energy density,low cost,and environmental compatibility.Despite these advantages,their development remains largely confined to experimental phase.A critical barrier to commercialization is the poor corrosion resistance of the anode resulting in low anodic efficiency.This article presents a comprehensive review of strategies aimed at improving the utilization efficiency of Mg anodes,with a particular focus on addressing corrosion issues from a microstructural standpoint.Firstly,the principle of Mg-air batteries has been outlined and the corrosion behavior has been discussed.The review then delves into a variety of representative anode materials.Special attention is given to innovative material designs that mitigate the challenges typically encountered by Mg-air batteries.Finally,the paper provides an outlook on future research directions,identifying critical technological barriers and highlighting areas that warrant further investigation.By offering a detailed analysis of material structures,this article aims to contribute valuable insights for advancing the development of high-performance Mg-air batteries.
基金financially supported by the National Key R&D Program of China(No.2016YFC1102500)the National Natural Science Foundation of China(No.51871020)the Fundamental Research Funds for the Central Universities(No.FRF-TP-19022A3Z)。
文摘In order to improve mechanical and corrosion properties of biodegradable pure Zn,a knowledge-based microstructure design is performed on Zn-Li alloy system composed of hard β-LiZn_(4) and soft Zn phases.Precipitation and multi-modal grain structure are designed to toughen β-LiZn_(4) while strengthen Zn,resulting in high strength and high ductility for both the phases.Needle-like secondary Zn precipitates form in β-LiZn4,while fine-scale networks of string-like β-LiZn4 precipitates form in Zn with a tri-modal grain structure.As a result,near-eutectic Zn-0.48 Li alloy with an outstanding combination of high strength and high ductility has been fabricated through hot-warm rolling,a novel fabrication process to realize the microstructure design.The as-rolled alloy has yield strength(YS) of 246 MPa,the ultimate tensile strength(UTS) of 395 MPa and elongation to failure(EL) of 47 %.Immersion test in simulated body fluid(SBF) for 30 days reveals that Li-rich products form preferentially at initial stage,followed by Zn-rich products with prolonged time.Aqueous insoluble Li_(2) CO_(3) forms a protective passivation film on the alloy surface,which suppresses the average corrosion rate from 81.2 μm/year at day one down dramatically to 18.2 μm/year at day five.Afterwards,the average corrosion rate increases slightly with decrease of Li2 CO_(3) content,which undulates around the clinical requirements on corrosion resistance(i.e.,20 μm/year) claimed for biodegradable metal stents.
文摘The effects of applied tensile strain on the coherent α_2→O-phase transformation in Ti-Al-Nb alloys are explored bycomputer simulation using a phase-field method. The focus is on the influence of the applied strain direction onthe microstructure and volume fraction of the O-phase precipitates. It is found that altering applied strain directioncan modify microstructure of Ti-25Al-10～12Nb (at. pct) alloy during α_2→O-phase transformation effectively andfull laminate microstructure in the Ti-25Al-10Nb (at. pct) alloy can be realized by an applied strain only along thedirection 30°away from the α_2 phase <1010> in magnitude equivalent to the stress-free transformation strain. Thesimulation also shows that not only the magnitude of applied strain but also the applied strain direction influencesthe O-phase volume fraction and the effect of strain direction on the volume fraction is up to 25%.
基金supported by the National Natural Science Foundation of China(Grant Nos.11972080,11972083 and 11991030)the Innovation Foundation of Maritime Defense Technologies Innovation Center(Grant No.JJ-2021-719-06).
文摘Pentamode acoustic cloak is promising for underwater sound control due to its solid nature and broadband efficiency,however its realization is only limited to simple cylindrical shape.In this work,we established a set of techniques for the microstructure design of elliptical pentamode acoustic cloak based on truss lattice model,including the inverse design of unit cell and algorithms for latticed cloak assembly.The designed cloak was numerically validated by the well wave concealing performance.The work proves that more general pentamode acoustic wave devices beyond simple cylindrical geometry are theoretically feasible,and sheds light on more practical design for waterborne sound manipulation.
基金financially supported by research university grantUniversiti Sains Malaysia RUI 1001/PBAHAN/811212teaching fellow scheme USM.9/25 Jld.ⅩⅢ。
文摘The influence of La_(2)O_(3)inclusion(0-3 wt%)on the micro structure,phase formation and mechanical properties of zirconia toughed alumina(ZTA)added with 5.0 wt%CeO_(2)was investigated.ZTA CeO_(2)composites were sintered at 1600℃for 4 h.The microstructure,phase formation,density,fracture toughness and hardness properties were characterised through FESEM,Microscopy Image Analysis Software and XRD diffractometer,Archimedes principle and Vickers indentation technique,respectively.The XRD,image processing and FESEM reveal the existence of LaAl_(11)O_(18).The addition of La_(2)O_(3)incites the sintering,microstructure refinement,densification of ZTA-CeO_(2)matrix and phase transformation.Hence,the hardness of ZTA-CeO_(2)ceramics is increased rapidly based on refinement of Al_(2)O_(3)grains,densification of ZTA-CeO_(2)composites and porosity reduction.It is observed that the fracture toughness is enhanced through in situ formation of elongated LaAl_(11)O_(18)grains.The addition of 0.7 wt%La_(2)O_(3)culminated in the achievement of the optimum findings for density(4.41 g/cm^(3)),porosity(0.46%),hardness(1792 HV)and fracture toughness(8.8 MPa·m^(1/2)).Nevertheless,excess La_(2)O_(3)is proven to be detrimental as it displays poor mechanical properties due to the poor compactness of numerous LaAl_(11)O_(18)grains,coarsening of Al_(2)O_(3)grains and decline in density.
基金Project supported by Plan of National Key Research and Development(2016YFB0700903)Major projects of Haishu District of Ningbo(201803A005)。
文摘LaCe-based sintered magnets with different microstructural features and distinct rare earth elemental distribution were designed by dual-alloy method.The sample prepared by fine LaCe-containing powder and coarse LaCe-free powder possesses higher remanence(~13.41 kGs),whereas another sample prepared by fine LaCe-free powder and coarse LaCe-containing powder possesses higher coercivity(~5.67 kOe).Additionally,these samples are with the same nominal compositions and their elemental distribution features are obviously different in matrix grains respectively.Their remanence difference is mainly affected by the saturation magnetization difference caused by the distribution variation of the rare earth elements at the matrix phase.The coercivity difference is affected by the component of the grain boundary phase between the adjacent grains and the distribution variation of the rare earth elements at the matrix phase.These findings may provide a new prospect for the utilization of LaCe mischmetal in 2:14:1-type permanent magnets.
基金supported by the National Natural Science Foundation of China (Nos. 51134013, and 51471044)funds for the central universities, key laboratory of basic research projects of Liaoning Province Department of Education (No. LZ2014007)the Natural Science Foundation of Liaoning Province (No. 2014028013)
文摘A series of CoCrFeNb_xNi（x values in molar ratio, x = 0, 0.25, 0.45, 0.5, 0.75, 1.0 and 1.2） high entropy alloys（HEAs） was prepared to investigate the alloying effect of Nb on the microstructures and mechanical properties. The results indicate that the prepared CoCrFeNb_xNi（x 〉 0） HEAs consist of a simple FCC solid solution phase and a Laves phase. The microstructures of the alloys change from an initial single-phase FCC solid solution structure（x = 0） to a hypoeutectic microstructure（x = 0.25）, then to a full eutectic microstructure（x = 0.45） and finally to a hypereutectic microstructure（0.5 〈 x 〈 1.2）. The compressive test results show that the Nb0.45（x = 0.45） alloy with a full eutectic microstructure possesses the highest compressive fracture strength of 2558 MPa and a fracture strain of 27.9%. The CoCrFeNi alloy exhibits an excellent compressive ductility, which can reach 50% height reduction without fracture. The Nb0.25 alloy with a hypoeutectic structure exhibits a larger plastic strain of 34.8%. With the increase of Nb content, increased hard/brittle Laves phase leads to a decrease of the plasticity and increases of the Vickers hardness and the wear resistance. The wear mass loss, width and depth of wear scar of the Nb1.2（x = 1.2） alloy with a hypereutectic structure are the lowest among all alloy systems, indicating that the wear resistance of the Nb1.2 alloy is the best one.
文摘Unbalanced properties for both fine-grained gamma and coarse-grained lamellar microstructures typically produced in gamma alloys are described. Efforts for the improvements are reviewed along with some experimental results. Empirical improvements have been made in cast alloys, which have led gamma alloys to a viable materials technology and to the development of various application areas for gas turbine engines as well as automotive engines. Efforts to understand fundamental and applied aspects leading to the improvements are assessed for wrought alloys. Optimization of microstructures through process control,innovative heat treatments, alloy chemistry modification and their combinations have progressed in the endeavor. Similar efforts have just begun for cast alloys where work on fundamental understanding has been lagging. Future directions are suggested for further improvements and predicted for the development of higher temperature/performance alloys.
