In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are i...In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are inspired by nature itself.It describes how new AM technologies(e.g.continuous liquid interface production and multiphoton polymerization,etc)and recent developments in more mature AM technologies(e.g.powder bed fusion,stereolithography,and extrusion-based bioprinting(EBB),etc)lead to more precise,efficient,and personalized biomedical components.EBB is a revolutionary topic creating intricate models with remarkable mechanical compatibility of metamaterials,for instance,stress elimination for tissue engineering and regenerative medicine,negative or zero Poisson’s ratio.By exploiting the designs of porous structures(e.g.truss,triply periodic minimal surface,plant/animal-inspired,and functionally graded lattices,etc),AM-made bioactive bone implants,artificial tissues,and organs are made for tissue replacement.The material palette of the AM metamaterials has high diversity nowadays,ranging from alloys and metals(e.g.cobalt-chromium alloys and titanium,etc)to polymers(e.g.biodegradable polycaprolactone and polymethyl methacrylate,etc),which could be even integrated within bioactive ceramics.These advancements are driving the progress of the biomedical field,improving human health and quality of life.展开更多
This paper presents a fully integrated platform that leverages hardware,software,and specially formulated O/W emulsions to provide localized mechanical stimuli for manipulating cellular behaviors.The system comprises ...This paper presents a fully integrated platform that leverages hardware,software,and specially formulated O/W emulsions to provide localized mechanical stimuli for manipulating cellular behaviors.The system comprises a hexapole magnetic tweezer device,position-based current calculation software,and biocompatible micro-robots embedded with magnetic microbeads for vibration-driven force generation.High-permeability materials in the tweezer tips,combined with fast-response current regulators,enable rapid and precise force control,ensuring uniform and continuous mechanical stimuli in the pico-newton range.Closed-loop control algorithms automatically adjust coil currents based on the micro-robot’s position,thereby compensating for potential hysteresis and optimizing system stability.Experimental results demonstrate stable operation at frequencies up to 4 Hz,with a theoretical possibility of extending to 8 Hz under a 2 A current,delivering mean forces around 20 pN at 1 Hz with a 57μm emulsion.Additionally,the platform allows fine-tuning of forces by altering emulsion size or bead concentrations,thereby providing researchers with a versatile approach to study apoptosis,proliferation,and the other mechanotransduction pathways.The biodegradable and cell-friendly emulsion serves as a protective membrane for the magnetic microbeads while effectively mimicking the mechanical properties of living cells.By bridging the gap between precise motion control and continuous vibrational force application,this novel platform offers a promising tool for advancing targeted cellular studies,fostering insights into tissue engineering,and improving cancer therapies.展开更多
The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack form...The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack formation mechanism were revealed.The yield strength and work hardening rate increase significantly with increasing impact strain rate.Deformation twinning and non-basal dislocation slip are the primary deformation mechanisms during testing.Contrary to crack initiation mechanism facilitated by adiabatic shear bands,we find that high-density co-axial nanocrystalline grains form near cracks,which leads to local softening and promotes crack initiation and rapid propagation.Most grains have similar<1^(-)21^(-)0>orientations,with unique misorientation of 24°,32°,62°,78°and 90°between adjacent grains,suggesting that these grains are primarily formed by interface transformation,which exhibits distinct differences from recrystallized grains.Our results shed light upon the dynamic mechanical response and crack formation mechanism in magnesium alloys under impact deformation.展开更多
Introducing Ti_(2)AlC particles into TiAl alloys can effectively improve their strength,but this can also lead to stress concentration at the interface,resulting in the reduction of ductility.Therefore,Mn is adopted t...Introducing Ti_(2)AlC particles into TiAl alloys can effectively improve their strength,but this can also lead to stress concentration at the interface,resulting in the reduction of ductility.Therefore,Mn is adopted to synergistically improve the strength and ductility of the Ti_(2)AlC/TiAl composite through solid solution and interface manipulation.The first-principles calculation shows the Ti-Mn bonds are formed at the Ti_(2)AlC/TiAl interface after Mn doping,characterized primarily by metallic bonds with some covalent bonding.This combination preserves strength while enhancing ductility.Then,Ti_(2)AlC/TiAl-Mn composite is prepared.The Ti_(2)AlC,with an average size of 1.6μm,is uniformly distributed within the TiAl matrix.Mn doping reduces the lamellar colony size and lamellar thickness by 25.1%and 27.4%,respectively.A small quantity of Mn accumulates at the boundaries of the lamellar colonies.The Mn content must be controlled to avoid segregation,which may negatively impact performance.The yield stress,ultimate compressive stress,fracture strain,and product of strength and plasticity of the Ti_(2)AlC/TiAl-Mn composite have been increased by 5.5%,11.5%,10.4%,and 23.0%,respectively,compared to those of the Ti_(2)AlC/TiAl composite.The enhancement in strength is due to the combined effects of grain refinement,solid solution of Mn,and twining strengthening.Grain refinement and twin strengthening also can reduce stress concentration and improve ductility.In addition,at the electronic level,the Ti-Mn bond formed at the interface is contributed to the improvement of ductility.展开更多
To address the insufficient prediction accuracy of multi-state parameters in electro-hydraulic servo material fatigue testing machines under complex loading and nonlinear coupling conditions,this paper proposes a mult...To address the insufficient prediction accuracy of multi-state parameters in electro-hydraulic servo material fatigue testing machines under complex loading and nonlinear coupling conditions,this paper proposes a multivariate sequence-to-sequence prediction model integrating a Long Short-Term Memory(LSTM)encoder,a Gated Recurrent Unit(GRU)decoder,and a multi-head attention mechanism.This approach enhances prediction accuracy and robustness across different control modes and load spectra by leveraging multi-channel inputs and cross-variable feature interactions,thereby capturing both short-term high-frequency dynamics and long-term slow drift characteristics.Experiments using long-term data from real test benches demonstrate that the model achieves a stable MSE below 0.01 on the validation set,with MAE and RMSE of approximately 0.018 and 0.052,respectively,and a coefficient of determination reaching 0.98.This significantly outperforms traditional identification methods and single RNN models.Sensitivity analysis indicates that a prediction stride of 10 achieves an optimal balance between accuracy and computational overhead.Ablation experiments validated the contribution of multi-head attention and decoder architecture to enhancing cross-variable coupling modeling capabilities.This model can be applied to residualdriven early warning in health monitoring,and risk assessment with scheme optimization in test design.It enables near-real-time deployment feasibility,providing a practical data-driven technical pathway for reliability assurance in advanced equipment.展开更多
In this study,a facile method was employed to synthesize strong,yet highly elastic polyurethane-urea(PUU)with typical characteristics and 94% optical transmittance.Graphene platelets(GNPs)were prepared and modified vi...In this study,a facile method was employed to synthesize strong,yet highly elastic polyurethane-urea(PUU)with typical characteristics and 94% optical transmittance.Graphene platelets(GNPs)were prepared and modified via a scalable and eco-friendly mechanochemical approach.The produced GNPs is at 1.6-nm thickness with high electrical conductivity of~950 S/m.The structure-property relations of PUU/GNP nanocomposites were comprehensively investigated through morphology and mechanical properties measurements.The strong interface and high-density hydrogen bonds between modified GNPs(M-GNPs)and PUU significantly enhanced the mechanical properties of the PUU nanocomposite.The PUU composite showed 66.7%and 36.2%increments in tensile and impact strengths,respectively,at 0.2 wt% M-GNPs.The reversible hydrogen bond between M-GNPs and PUU endowed the nanocomposite with self-healing properties achieving 97.8% healing efficiency of the strength after 5 h at 120℃.This study demonstrates the importance of surface modification and provides a simple yet robust approach for preparing high-performance and functional PUU/graphene composites.展开更多
This study proposes a lightweight apple detection method employing cascaded knowledge distillation(KD)to address the critical challenges of excessive parameters and high deployment costs in existing models.We introduc...This study proposes a lightweight apple detection method employing cascaded knowledge distillation(KD)to address the critical challenges of excessive parameters and high deployment costs in existing models.We introduce a Lightweight Feature Pyramid Network(LFPN)integrated with Lightweight Downsampling Convolutions(LDConv)to substantially reduce model complexity without compromising accuracy.A Lightweight Multi-channel Attention(LMCA)mechanism is incorporated between the backbone and neck networks to effectively suppress complex background interference in orchard environments.Furthermore,model size is compressed via Group_Slim channel pruning combined with a cascaded distillation strategy.Experimental results demonstrate that the proposed model achieves a 1%higherAverage Precision(AP)than the baselinewhilemaintaining extreme lightweight advantages(only 800 k parameters).Notably,the two-stage KD version achieves over 20 Frames Per Second(FPS)on Central Processing Unit(CPU)devices,confirming its practical deployability in real-world applications.展开更多
Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that p...Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.展开更多
Aqueous zinc metal batteries(AZMBs)face significant challenges in achieving reversibility and cycling stability,primarily due to hydrogen evolution reactions(HER)and zinc dendrite growth.In this study,by employing car...Aqueous zinc metal batteries(AZMBs)face significant challenges in achieving reversibility and cycling stability,primarily due to hydrogen evolution reactions(HER)and zinc dendrite growth.In this study,by employing carefully designed cells that approximate the structural characteristics of practical batteries,we revisit this widely held view through in-operando X-ray radiography to examine zinc dendrite formation and HER under nearpractical operating conditions.While conventional understanding emphasizes the severity of these processes,our findings suggest that zinc dendrites and HER are noticeably less pronounced in dense,real-operation configurations compared to modified cells,possibly due to a more uniform electric field and the suppression of triple-phase boundaries.This study indicates that other components,such as degradation at the cathode current collector interface and configuration mismatches within the full cell,may also represent important barriers to the practical application of AZMBs,particularly during the early stages of electrodeposition.展开更多
Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)g...Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)great potential for high-quality color displays with a wide color gamut and pure color emission.Although laboratory-scale Pe LEDs have achieved neartheoretical efficiencies,challenges such as achieving uniform large-area films,improving material stability,and enhancing patterning precision remain barriers to commercialization.This review presents a systematic analysis of scalable manufacturing and precision patterning strategies for Pe LEDs,focusing on their applications in large-area lighting and full-color displays.Fabrication methods are categorized into film deposition techniques(spin-coating,blade-coating,and thermal evaporation)and patterning strategies,including top-down(photolithography,laser/e-beam lithography,and nanoimprinting)and bottom-up(patterned crystal growth,inkjet printing,and electrohydrodynamic jet printing)approaches.In this review,we discuss the advantages and limitations of each strategy,highlight current challenges,and outlook possible pathways towards scalable,high-performance Pe LEDs for advanced optoelectronic applications.展开更多
Biofabrication and biomanufacturing are rapidly transforming how materials,therapeutics,and functional biological constructs are produced.These fields integrate developments in sustainable biomaterials,precision fabri...Biofabrication and biomanufacturing are rapidly transforming how materials,therapeutics,and functional biological constructs are produced.These fields integrate developments in sustainable biomaterials,precision fabrication,biological systems,and data-driven engineering to produce scalable,efficient,and environmentally aligned production pathways.This review highlights recent scientific advances led by researchers in Singapore,focusing on three interconnected pillars:sustainable bio derived materials,enabling fabrication and manufacturing technologies,and emerging applications.We first examine the expanding use of biomass-derived feedstocks,including human hair keratin,aquaculture side-streams,and plant-derived polysaccharides,which support circular and resource-conscious material development.We then present advances in biofabrication technologies,including electrospinning,three-dimensional bioprinting,and metal additive manufacturing,that enable improved control over the structure,function,and manufacturability of biomedical and functional constructs.Emerging applications,such as machine learning-assisted additive manufacturing,food biomanufacturing,regenerative cell therapy,microneedles,and bioelectronics,exemplify how biofabrication and biomanufacturing are increasingly interrelated across the health,materials,and technological domains.These research contributions from Singapore exemplify how sustainable feedstocks,digital and automated fabrication platforms,and biologically driven applications are shaping the evolving landscape of biofabrication and biomanufacturing.The convergence of materials science,biological engineering,and advanced manufacturing continues to enable new opportunities for innovation in biomedical,industrial,and societal contexts.展开更多
Mechanical debris is an important product of friction wear, which is also a crucial approach to know the running status of a machine. Many studies have been conducted on mechanical debris in related fields such as tri...Mechanical debris is an important product of friction wear, which is also a crucial approach to know the running status of a machine. Many studies have been conducted on mechanical debris in related fields such as tribology, instrument, and diagnosis. This paper presents a comprehensive review of these studies, which summarizes wear mechanisms（e.g., abrasive wear, fatigue wear, and adhesive wear） and debris features（e.g., concentration（number）, size, morphology, and composition）, analyzes detection methods principles（e.g., offline： spectrograph and ferrograph, and online： optical method, inductive method, resistive-capacitive method, and acoustic method）,reviews developments of online inductive methods, and investigates the progress of debris-based diagnosis. Finally, several notable problems are discussed for further studies.展开更多
Ultra-fine grained （UFG） cylindrical tubes were produced via recently developed tubular channel angular pressing （TCAP） process through different passes from as-cast AZ91 magnesium alloy. The microstructure and me...Ultra-fine grained （UFG） cylindrical tubes were produced via recently developed tubular channel angular pressing （TCAP） process through different passes from as-cast AZ91 magnesium alloy. The microstructure and mechanical properties of processed tube through one to four passes of TCAP process at 200℃ were investigated. Microhardness of the processed tube was increased to 98.5 HV after one pass from an initial value of 67 Hr. An increase in the number of passes from one to higher number of passes has no more effect on the microhardness. Yield and ultimate strengths were increased by 4.3 and 1.4 times compared to those in as-cast condition. Notable increase in the strength was achieved after one pass of TCAP while higher number of passes has no more effect. Microstructural investigation shows notable decrease in the grain size to around 500 nm from the primary value of - 150 μm. Dissolution and distribution of hard MglTAI12 phase in the grain boundaries of dynamically recrystallized UFG AZ91 with a mean grain size of - 500 nm was an interesting issue of TCAP processing at 200 ℃ compared to other severe plastic deformation processes.展开更多
The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between d...The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between depth of overdischarge and mechanical properties is still a significant challenge.Studying the correlation between depth of overdischarge and mechanical properties is of great significance to improving the energy density and the ability to resist abuse of the batteries.In this paper,the mechanical properties of the battery materials during the whole process of overdischarge from discharge to complete failure were studied.The effects of depth of overdischarge on the elastic modulus and hardness of the cathode of the battery,the tensile strength and the thermal shrinkage rate of the separator,and the performance of binder were investigated.The precipitation of Cu dendrites on the separator and cathode after dissolution of anode copper foil is a key factor affecting the performance of battery materials.The Cu dendrites attached to the cathode penetrate the separator,causing irreversible damage to the coating and base film of the separator,which leads to a sharp decline in the tensile strength,thermal shrinkage rate and other properties of the separator.In addition,the Cu dendrites wrapping the cathode active particles reduce the adhesion of the active particles binder.Meanwhile,the active particles are damaged,resulting in a significant decrease in the elastic modulus and hardness of the cathode.展开更多
Ultrafine-grained(UFG) high purity aluminum exhibits a variety of attractive mechanical properties and special deformation behavior. Equal channel angular pressing(ECAP) process can be used to easily and effectively r...Ultrafine-grained(UFG) high purity aluminum exhibits a variety of attractive mechanical properties and special deformation behavior. Equal channel angular pressing(ECAP) process can be used to easily and effectively refine metals. The microstructure and microtexture evolutions and grain boundary characteristics of the high purity aluminum(99.998%) processed by ECAP at room temperature are investigated by means of TEM and EBSD. The results indicate that the shear deformation resistance increases with repeated EACP passes, and equiaxed grains with an average size of 0.9 μm in diameter are formed after five passes. Although the orientations distribution of grains tends to evolve toward random orientations, and microtextures(80°, 35°, 0°),(40°, 75°, 45°) and(0°, 85°, 45°) peak in the sample after five passes. The grain boundaries in UFG aluminum are high-angle geometrically necessary boundaries. It is suggested that the continuous dynamic recrystallization is responsible for the formation of ultrafine grains in high purity aluminum. Microstructure evolution in the high purity aluminum during ECAP is proposed.展开更多
Mechanical metamaterials can be defined as a class of architected materials that exhibit unprecedented mechanical properties derived from designed artificial architectures rather than their constituent materials.While...Mechanical metamaterials can be defined as a class of architected materials that exhibit unprecedented mechanical properties derived from designed artificial architectures rather than their constituent materials.While macroscale and simple layouts can be realized by conventional top-down manufacturing approaches,many of the sophisticated designs at various length scales remain elusive,due to the lack of adequate manufacturing methods.Recent progress in additive manufacturing(AM)has led to the realization of a myriad of novel metamaterial concepts.AM methods capable of fabricating microscale architectures with high resolution,arbitrary complexity,and high feature fidelity have enabled the rapid development of architected meta materials and drastically reduced the design-computation and experimental-validation cycle.This paper first provides a detailed review of various topologies based on the desired mechanical properties,including stiff,strong,and auxetic(negative Poisson’s ratio)metamaterials,followed by a discussion of the AM technologies capable of fabricating these metamaterials.Finally,we discuss current challenges and recommend future directions for AM and mechanical metamaterials.展开更多
The effect of amorphous film on the deformation mechanism and mechanical properties of 6 H-SiC were systematically explored by a combination of both experiments and molecular dynamic(MD)simulations in nanoindentation....The effect of amorphous film on the deformation mechanism and mechanical properties of 6 H-SiC were systematically explored by a combination of both experiments and molecular dynamic(MD)simulations in nanoindentation.The experimental results showed that the plastic deformation of surface-modified6 H-SiC is mainly accommodated by dislocation activities in the subsurface and an amorphous layer with uniform thickness.The MD results indicated that the amorphous layer on the surface of the residual indentation mark consists of both amorphous SiO_(2)and SiC due to direct amorphization.In addition,the amorphous SiO_(2)film undergoes densification and then ruptures with the indentation depth increases.The modulus and hardness increase with increasing the indentation depth at the initial stage but will reach their stable values equivalent to monocrystalline 6 H-SiC.展开更多
Highly porous 316L stainless steel parts were produced by using a powder metallurgy process, which includes the selective laser sintering(SLS) and traditional sintering. Porous 316L stainless steel suitable for medica...Highly porous 316L stainless steel parts were produced by using a powder metallurgy process, which includes the selective laser sintering(SLS) and traditional sintering. Porous 316L stainless steel suitable for medical applications was successfully fabricated in the porosity range of 40%-50% (volume fraction) by controlling the SLS parameters and sintering behaviour. The porosity of the sintered compacts was investigated as a function of the SLS parameters and the furnace cycle. Compressive stress and elastic modulus of the 316L stainless steel material were determined. The compressive strength was found to be ranging from 21 to 32 MPa and corresponding elastic modulus ranging from 26 to 43 GPa. The present parts are promising for biomedical applications since the optimal porosity of implant materials for ingrowths of new-bone tissues is in the range of 20%-59% (volume fraction) and mechanical properties are matching with human bone.展开更多
Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of mate...Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of materials.A smart use of materials leads to reduced fuel consumption and lower operating costs,making them highly desirable for aircraft manufacturers.Furthermore,the customizable properties of lattice structures allow for tailoring to specific design requirements,leading to improved performance and safety for aircraft.These advantages make lattice structures an important focus for research and development in the aviation industry.This paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V,designed for use in an anti-ice system.The truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical properties.Results showed that lattice trusses exhibited high levels of compressive strength,making them suitable for use in applications where mechanical resistance and durability are critical,such as in anti-ice systems.We also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical properties.The study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems,as well as other areas where high strength-to-weight ratios are required.The results of this research contribute to the development of lightweight,efficient,and durable anti-ice systems for use in aviation and other industries.展开更多
Here,a systematic investigation was made on the interphase strengthening effects induced superior me-chanical performances of multiphase high-entropy alloys(HEAs)at micro/nano-scale,compared with sin-gle phase HEAs.A ...Here,a systematic investigation was made on the interphase strengthening effects induced superior me-chanical performances of multiphase high-entropy alloys(HEAs)at micro/nano-scale,compared with sin-gle phase HEAs.A pillar compression test under a scanning electron microscope(SEM)was performed on the individual face centered cubic(FCC),body centered cubic(BCC),and mixed-phases with different di-ameters in a Fe_(24)Co_(25)Ni_(24)Cr_(23)Al_(4)HEA using focused ion beam(FIB)milling and a nanoindenter equipped with a flat punch.The stress-strain response of pillar underneath the indenter was selected to explore the diameter/phase-dependent size effect,the periodically fluctuation of local stress,and strain hardening.It was revealed that the pillars at the interphase exhibited significantly higher strength,compared with the FCC and BCC pillars.An experiment also verified the coincident mechanical size effects independent with the type of phases.The stress responses in the mixed-phase pillars manifested as a distinct transition from the dramatic drop to the minor fluctuation during the post-yield stages with the increasing strain,indicating the propagation of Al-Ni enriched solid solution phase(BCC1)under compression.Except the BCC1 phase,numerous dislocations were observed in the post-deformed pillars,particularly serving as the major source to enhance the strain hardening of BCC pillars.展开更多
基金sponsored by the Science and Technology Program of Hubei Province,China(2022EHB020,2023BBB096)support provided by Centre of the Excellence in Production Research(XPRES)at KTH。
文摘In this review,we propose a comprehensive overview of additive manufacturing(AM)technologies and design possibilities in manufacturing metamaterials for various applications in the biomedical field,of which many are inspired by nature itself.It describes how new AM technologies(e.g.continuous liquid interface production and multiphoton polymerization,etc)and recent developments in more mature AM technologies(e.g.powder bed fusion,stereolithography,and extrusion-based bioprinting(EBB),etc)lead to more precise,efficient,and personalized biomedical components.EBB is a revolutionary topic creating intricate models with remarkable mechanical compatibility of metamaterials,for instance,stress elimination for tissue engineering and regenerative medicine,negative or zero Poisson’s ratio.By exploiting the designs of porous structures(e.g.truss,triply periodic minimal surface,plant/animal-inspired,and functionally graded lattices,etc),AM-made bioactive bone implants,artificial tissues,and organs are made for tissue replacement.The material palette of the AM metamaterials has high diversity nowadays,ranging from alloys and metals(e.g.cobalt-chromium alloys and titanium,etc)to polymers(e.g.biodegradable polycaprolactone and polymethyl methacrylate,etc),which could be even integrated within bioactive ceramics.These advancements are driving the progress of the biomedical field,improving human health and quality of life.
基金part supported by JSPS KAKENHI Grant Number JP23K28396.
文摘This paper presents a fully integrated platform that leverages hardware,software,and specially formulated O/W emulsions to provide localized mechanical stimuli for manipulating cellular behaviors.The system comprises a hexapole magnetic tweezer device,position-based current calculation software,and biocompatible micro-robots embedded with magnetic microbeads for vibration-driven force generation.High-permeability materials in the tweezer tips,combined with fast-response current regulators,enable rapid and precise force control,ensuring uniform and continuous mechanical stimuli in the pico-newton range.Closed-loop control algorithms automatically adjust coil currents based on the micro-robot’s position,thereby compensating for potential hysteresis and optimizing system stability.Experimental results demonstrate stable operation at frequencies up to 4 Hz,with a theoretical possibility of extending to 8 Hz under a 2 A current,delivering mean forces around 20 pN at 1 Hz with a 57μm emulsion.Additionally,the platform allows fine-tuning of forces by altering emulsion size or bead concentrations,thereby providing researchers with a versatile approach to study apoptosis,proliferation,and the other mechanotransduction pathways.The biodegradable and cell-friendly emulsion serves as a protective membrane for the magnetic microbeads while effectively mimicking the mechanical properties of living cells.By bridging the gap between precise motion control and continuous vibrational force application,this novel platform offers a promising tool for advancing targeted cellular studies,fostering insights into tissue engineering,and improving cancer therapies.
基金support from the National Natural Science Foundation of China(Grant Nos.52301137,51974097,52364050)the Natural Science Special Foundation of Guizhou University(No.(2023)20)+1 种基金Guizhou Province Science and Technology Project(Grant Nos.[2023]001,[2019]2163)Guiyang city Science and Technology Project(Grant No.[2023]48-16).
文摘The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack formation mechanism were revealed.The yield strength and work hardening rate increase significantly with increasing impact strain rate.Deformation twinning and non-basal dislocation slip are the primary deformation mechanisms during testing.Contrary to crack initiation mechanism facilitated by adiabatic shear bands,we find that high-density co-axial nanocrystalline grains form near cracks,which leads to local softening and promotes crack initiation and rapid propagation.Most grains have similar<1^(-)21^(-)0>orientations,with unique misorientation of 24°,32°,62°,78°and 90°between adjacent grains,suggesting that these grains are primarily formed by interface transformation,which exhibits distinct differences from recrystallized grains.Our results shed light upon the dynamic mechanical response and crack formation mechanism in magnesium alloys under impact deformation.
基金supported by the National Natural Science Foundation of China(Nos.52371031 and 52574435)the Science and Technology Development Program of Jilin Province,China(No.20250102103JC)+2 种基金the Science and Technology Development Program of Changchun City,China(No.23JQ03)Changbaishan Laboratory,China(No.CBS2025004-03)the Undergraduate Innovation Fund of Jilin University,China(No.S202410183310).
文摘Introducing Ti_(2)AlC particles into TiAl alloys can effectively improve their strength,but this can also lead to stress concentration at the interface,resulting in the reduction of ductility.Therefore,Mn is adopted to synergistically improve the strength and ductility of the Ti_(2)AlC/TiAl composite through solid solution and interface manipulation.The first-principles calculation shows the Ti-Mn bonds are formed at the Ti_(2)AlC/TiAl interface after Mn doping,characterized primarily by metallic bonds with some covalent bonding.This combination preserves strength while enhancing ductility.Then,Ti_(2)AlC/TiAl-Mn composite is prepared.The Ti_(2)AlC,with an average size of 1.6μm,is uniformly distributed within the TiAl matrix.Mn doping reduces the lamellar colony size and lamellar thickness by 25.1%and 27.4%,respectively.A small quantity of Mn accumulates at the boundaries of the lamellar colonies.The Mn content must be controlled to avoid segregation,which may negatively impact performance.The yield stress,ultimate compressive stress,fracture strain,and product of strength and plasticity of the Ti_(2)AlC/TiAl-Mn composite have been increased by 5.5%,11.5%,10.4%,and 23.0%,respectively,compared to those of the Ti_(2)AlC/TiAl composite.The enhancement in strength is due to the combined effects of grain refinement,solid solution of Mn,and twining strengthening.Grain refinement and twin strengthening also can reduce stress concentration and improve ductility.In addition,at the electronic level,the Ti-Mn bond formed at the interface is contributed to the improvement of ductility.
基金supported by Natural Science Foundation of China(NSFC),Grant number 5247052693.
文摘To address the insufficient prediction accuracy of multi-state parameters in electro-hydraulic servo material fatigue testing machines under complex loading and nonlinear coupling conditions,this paper proposes a multivariate sequence-to-sequence prediction model integrating a Long Short-Term Memory(LSTM)encoder,a Gated Recurrent Unit(GRU)decoder,and a multi-head attention mechanism.This approach enhances prediction accuracy and robustness across different control modes and load spectra by leveraging multi-channel inputs and cross-variable feature interactions,thereby capturing both short-term high-frequency dynamics and long-term slow drift characteristics.Experiments using long-term data from real test benches demonstrate that the model achieves a stable MSE below 0.01 on the validation set,with MAE and RMSE of approximately 0.018 and 0.052,respectively,and a coefficient of determination reaching 0.98.This significantly outperforms traditional identification methods and single RNN models.Sensitivity analysis indicates that a prediction stride of 10 achieves an optimal balance between accuracy and computational overhead.Ablation experiments validated the contribution of multi-head attention and decoder architecture to enhancing cross-variable coupling modeling capabilities.This model can be applied to residualdriven early warning in health monitoring,and risk assessment with scheme optimization in test design.It enables near-real-time deployment feasibility,providing a practical data-driven technical pathway for reliability assurance in advanced equipment.
基金The National Natural Science Foundation of China(No.52173077)the Liaoning Provincial Department of Education Series Project(No.LJKZ0187)+1 种基金Natural Science Foundation of Liaoning Province(No.2023-MS-239)Liaoning BaiQianWan Talents Program(No.2021921081)。
文摘In this study,a facile method was employed to synthesize strong,yet highly elastic polyurethane-urea(PUU)with typical characteristics and 94% optical transmittance.Graphene platelets(GNPs)were prepared and modified via a scalable and eco-friendly mechanochemical approach.The produced GNPs is at 1.6-nm thickness with high electrical conductivity of~950 S/m.The structure-property relations of PUU/GNP nanocomposites were comprehensively investigated through morphology and mechanical properties measurements.The strong interface and high-density hydrogen bonds between modified GNPs(M-GNPs)and PUU significantly enhanced the mechanical properties of the PUU nanocomposite.The PUU composite showed 66.7%and 36.2%increments in tensile and impact strengths,respectively,at 0.2 wt% M-GNPs.The reversible hydrogen bond between M-GNPs and PUU endowed the nanocomposite with self-healing properties achieving 97.8% healing efficiency of the strength after 5 h at 120℃.This study demonstrates the importance of surface modification and provides a simple yet robust approach for preparing high-performance and functional PUU/graphene composites.
基金funded by Jilin Provincial Department of Education Project Fund,grant number JJKH20240315KJthe National Natural Science Foundation of China under Grant 52175538.
文摘This study proposes a lightweight apple detection method employing cascaded knowledge distillation(KD)to address the critical challenges of excessive parameters and high deployment costs in existing models.We introduce a Lightweight Feature Pyramid Network(LFPN)integrated with Lightweight Downsampling Convolutions(LDConv)to substantially reduce model complexity without compromising accuracy.A Lightweight Multi-channel Attention(LMCA)mechanism is incorporated between the backbone and neck networks to effectively suppress complex background interference in orchard environments.Furthermore,model size is compressed via Group_Slim channel pruning combined with a cascaded distillation strategy.Experimental results demonstrate that the proposed model achieves a 1%higherAverage Precision(AP)than the baselinewhilemaintaining extreme lightweight advantages(only 800 k parameters).Notably,the two-stage KD version achieves over 20 Frames Per Second(FPS)on Central Processing Unit(CPU)devices,confirming its practical deployability in real-world applications.
基金financially supported by research grants from Innovative Research Group Project of National Natural Science Foundation of China(52021004)the National Key Research and Development Program of China(2022YFB3803300)+1 种基金the National Natural Science Foundation of China(62474026,62205140,12204071)the China Postdoctoral Science Foundation(2022M710532)。
文摘Thermocells are garnering increasing attention as a promising thermoelectric technology for harvesting low-grade heat.However,their performance is often limited by the scarcity of high-performance redox couples that possess both high thermopower and rapid redox kinetics.This work addresses this challenge by leveraging our recently developed copper(Ⅰ/Ⅱ)(Cu^(+)/Cu^(2+))redox couple.We significantly enhance the performance of Cu-based liquid thermocells by integrating a thermosensitive crystallization process with etched carbon cloth electrodes,achieving synergistic improvements in thermodynamic and kinetic performance.The thermosensitive crystallization process establishes a persistent Cu^(2+)concentration gradient,boosting the thermopower from 1.47 to 2.93 mV K^(-1).Moreover,the etched carbon cloth electrodes provide a larger electroactive surface area and demonstrate a higher current density.Consequently,the optimized Cu^(+)/Cu^(2+)system achieved an exceptional normalized power density P_(max)(ΔT)^(-2)of 3.97 mW m^(-2)K^(-2).A thermocell module comprised of 20 cells directly power various electronic devices at a temperature difference of 40 K.This work successfully exhibits potential of Cu^(+)/Cu^(2+)redox couple in thermoelectric conversion and introduces a valuable redox couple for highperformance thermocells.
基金the fundamental Research Funds for the central Universities(x2wjD2240360)for the funding supportMeanwhile,Engineering and Physical Sciences Research Council(EPSRC,EP/V027433/3)+2 种基金UK Research and Innovation(UKRI)under the UK government’s Horizon Europe funding(101077226,EP/Y008707/1)Faraday Institution(EP/S003053/1)Degradation project(FIRG001),Royal Society(IEC\NSFC\233361),QUB Agility Fund and Wright Technology and Research Centre(W-Tech,R5240MEE)Funding from UK aid from the UK Government through the Faraday Institution and the Transforming Energy Access Programme(Grant number FIRG050-Device engineering of Zn-based hybrid micro-flow batteries and by-product H2 collection for Emerging Economies)。
文摘Aqueous zinc metal batteries(AZMBs)face significant challenges in achieving reversibility and cycling stability,primarily due to hydrogen evolution reactions(HER)and zinc dendrite growth.In this study,by employing carefully designed cells that approximate the structural characteristics of practical batteries,we revisit this widely held view through in-operando X-ray radiography to examine zinc dendrite formation and HER under nearpractical operating conditions.While conventional understanding emphasizes the severity of these processes,our findings suggest that zinc dendrites and HER are noticeably less pronounced in dense,real-operation configurations compared to modified cells,possibly due to a more uniform electric field and the suppression of triple-phase boundaries.This study indicates that other components,such as degradation at the cathode current collector interface and configuration mismatches within the full cell,may also represent important barriers to the practical application of AZMBs,particularly during the early stages of electrodeposition.
基金supported by 14th Five-Year Plan Key R&D Plan,Ministry of Science and Technology of the People’s Republic of China,2024YFB3409002National Natural Science Foundation of China,12302142+4 种基金HKUSTHKUST(GZ)Collaborative Research Scheme,G035Yangcheng Scholars Research Project-Leading Talent Training Project,2024312156Guangzhou-HKUST(GZ)Joint Funding Scheme,2023A03J0157Guangzhou Basic and Applied Basic Research Project,2024A04J4765Shenzhen Basic Research Project,JCYJ20220530114417040。
文摘Owing to the exceptional optoelectronic properties,metal halide perovskites have emerged as leading semiconductor materials for next-generation display technologies,providing perovskite light-emitting diodes(Pe LEDs)great potential for high-quality color displays with a wide color gamut and pure color emission.Although laboratory-scale Pe LEDs have achieved neartheoretical efficiencies,challenges such as achieving uniform large-area films,improving material stability,and enhancing patterning precision remain barriers to commercialization.This review presents a systematic analysis of scalable manufacturing and precision patterning strategies for Pe LEDs,focusing on their applications in large-area lighting and full-color displays.Fabrication methods are categorized into film deposition techniques(spin-coating,blade-coating,and thermal evaporation)and patterning strategies,including top-down(photolithography,laser/e-beam lithography,and nanoimprinting)and bottom-up(patterned crystal growth,inkjet printing,and electrohydrodynamic jet printing)approaches.In this review,we discuss the advantages and limitations of each strategy,highlight current challenges,and outlook possible pathways towards scalable,high-performance Pe LEDs for advanced optoelectronic applications.
文摘Biofabrication and biomanufacturing are rapidly transforming how materials,therapeutics,and functional biological constructs are produced.These fields integrate developments in sustainable biomaterials,precision fabrication,biological systems,and data-driven engineering to produce scalable,efficient,and environmentally aligned production pathways.This review highlights recent scientific advances led by researchers in Singapore,focusing on three interconnected pillars:sustainable bio derived materials,enabling fabrication and manufacturing technologies,and emerging applications.We first examine the expanding use of biomass-derived feedstocks,including human hair keratin,aquaculture side-streams,and plant-derived polysaccharides,which support circular and resource-conscious material development.We then present advances in biofabrication technologies,including electrospinning,three-dimensional bioprinting,and metal additive manufacturing,that enable improved control over the structure,function,and manufacturability of biomedical and functional constructs.Emerging applications,such as machine learning-assisted additive manufacturing,food biomanufacturing,regenerative cell therapy,microneedles,and bioelectronics,exemplify how biofabrication and biomanufacturing are increasingly interrelated across the health,materials,and technological domains.These research contributions from Singapore exemplify how sustainable feedstocks,digital and automated fabrication platforms,and biologically driven applications are shaping the evolving landscape of biofabrication and biomanufacturing.The convergence of materials science,biological engineering,and advanced manufacturing continues to enable new opportunities for innovation in biomedical,industrial,and societal contexts.
基金supported by the National Natural Science Foundation of China(Nos.51620105010 and 51575019)the National Basic Research Program of China(No.2014CB046402)Singapore Energy Innovation Research Programme(Gas Technology Grant No.NRF2014EWT-EIRP003-014)
文摘Mechanical debris is an important product of friction wear, which is also a crucial approach to know the running status of a machine. Many studies have been conducted on mechanical debris in related fields such as tribology, instrument, and diagnosis. This paper presents a comprehensive review of these studies, which summarizes wear mechanisms（e.g., abrasive wear, fatigue wear, and adhesive wear） and debris features（e.g., concentration（number）, size, morphology, and composition）, analyzes detection methods principles（e.g., offline： spectrograph and ferrograph, and online： optical method, inductive method, resistive-capacitive method, and acoustic method）,reviews developments of online inductive methods, and investigates the progress of debris-based diagnosis. Finally, several notable problems are discussed for further studies.
基金financially supported by Iran National Science Foundation(INSF)
文摘Ultra-fine grained （UFG） cylindrical tubes were produced via recently developed tubular channel angular pressing （TCAP） process through different passes from as-cast AZ91 magnesium alloy. The microstructure and mechanical properties of processed tube through one to four passes of TCAP process at 200℃ were investigated. Microhardness of the processed tube was increased to 98.5 HV after one pass from an initial value of 67 Hr. An increase in the number of passes from one to higher number of passes has no more effect on the microhardness. Yield and ultimate strengths were increased by 4.3 and 1.4 times compared to those in as-cast condition. Notable increase in the strength was achieved after one pass of TCAP while higher number of passes has no more effect. Microstructural investigation shows notable decrease in the grain size to around 500 nm from the primary value of - 150 μm. Dissolution and distribution of hard MglTAI12 phase in the grain boundaries of dynamically recrystallized UFG AZ91 with a mean grain size of - 500 nm was an interesting issue of TCAP processing at 200 ℃ compared to other severe plastic deformation processes.
基金supported by the National Natural Science Foundation of China(92266206,52227810)the Jilin Province Science and Technology Development Plan(YDZJ202101ZYTS129)the Fundamental Research Funds for the Central Universities(2022-JCXK-11)。
文摘The degradation of mechanical properties of overdischarge battery materials manifests as a significant effect on the energy density,safety,and cycle life of the batteries.However,establishing the correlation between depth of overdischarge and mechanical properties is still a significant challenge.Studying the correlation between depth of overdischarge and mechanical properties is of great significance to improving the energy density and the ability to resist abuse of the batteries.In this paper,the mechanical properties of the battery materials during the whole process of overdischarge from discharge to complete failure were studied.The effects of depth of overdischarge on the elastic modulus and hardness of the cathode of the battery,the tensile strength and the thermal shrinkage rate of the separator,and the performance of binder were investigated.The precipitation of Cu dendrites on the separator and cathode after dissolution of anode copper foil is a key factor affecting the performance of battery materials.The Cu dendrites attached to the cathode penetrate the separator,causing irreversible damage to the coating and base film of the separator,which leads to a sharp decline in the tensile strength,thermal shrinkage rate and other properties of the separator.In addition,the Cu dendrites wrapping the cathode active particles reduce the adhesion of the active particles binder.Meanwhile,the active particles are damaged,resulting in a significant decrease in the elastic modulus and hardness of the cathode.
基金Project(12JJ2028)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(201308430093)supported by the China Scholarship CouncilProjects(201012200006,2013zzts185,2012zzts066)supported by the Freedom Explore Program of Central South University,China
文摘Ultrafine-grained(UFG) high purity aluminum exhibits a variety of attractive mechanical properties and special deformation behavior. Equal channel angular pressing(ECAP) process can be used to easily and effectively refine metals. The microstructure and microtexture evolutions and grain boundary characteristics of the high purity aluminum(99.998%) processed by ECAP at room temperature are investigated by means of TEM and EBSD. The results indicate that the shear deformation resistance increases with repeated EACP passes, and equiaxed grains with an average size of 0.9 μm in diameter are formed after five passes. Although the orientations distribution of grains tends to evolve toward random orientations, and microtextures(80°, 35°, 0°),(40°, 75°, 45°) and(0°, 85°, 45°) peak in the sample after five passes. The grain boundaries in UFG aluminum are high-angle geometrically necessary boundaries. It is suggested that the continuous dynamic recrystallization is responsible for the formation of ultrafine grains in high purity aluminum. Microstructure evolution in the high purity aluminum during ECAP is proposed.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(2021B0301030001)project supported by the Space Utilization System of China Manned Space Engineering(KJZ-YY-WCL03)+6 种基金National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact(6142902210109)National Key Research and Development Program of China(2018YFB0905600 and 2017YFB0310400)National Natural Science Foundation of China(51472188 and 51521001)Natural Research Funds of Hubei Province(2016CFB583)Natural Research Funds of Shenzhen,Fundamental Research Funds for the Central Universities China,State Key Laboratory of Advanced Electromagnetic Engineering and Technology(Huazhong University of Science and Technology)the Science and Technology Project of the Global Energy Interconnection Research Institute Co.,Ltd.(SGGR0000WLJS1801080)the 111 Project(B13035)。
文摘Mechanical metamaterials can be defined as a class of architected materials that exhibit unprecedented mechanical properties derived from designed artificial architectures rather than their constituent materials.While macroscale and simple layouts can be realized by conventional top-down manufacturing approaches,many of the sophisticated designs at various length scales remain elusive,due to the lack of adequate manufacturing methods.Recent progress in additive manufacturing(AM)has led to the realization of a myriad of novel metamaterial concepts.AM methods capable of fabricating microscale architectures with high resolution,arbitrary complexity,and high feature fidelity have enabled the rapid development of architected meta materials and drastically reduced the design-computation and experimental-validation cycle.This paper first provides a detailed review of various topologies based on the desired mechanical properties,including stiff,strong,and auxetic(negative Poisson’s ratio)metamaterials,followed by a discussion of the AM technologies capable of fabricating these metamaterials.Finally,we discuss current challenges and recommend future directions for AM and mechanical metamaterials.
基金financially supported by the Guangdong Specific Discipline Project(No.2020ZDZX2006)Shenzhen Key Laboratory of Cross-scale Manufacturing Mechanics Project(No.ZDSYS20200810171201007)undertaken with the assistance of the resources provided at the NCI National Facility systems through the National Computational Merit Allocation Scheme supported by the Australian Government。
文摘The effect of amorphous film on the deformation mechanism and mechanical properties of 6 H-SiC were systematically explored by a combination of both experiments and molecular dynamic(MD)simulations in nanoindentation.The experimental results showed that the plastic deformation of surface-modified6 H-SiC is mainly accommodated by dislocation activities in the subsurface and an amorphous layer with uniform thickness.The MD results indicated that the amorphous layer on the surface of the residual indentation mark consists of both amorphous SiO_(2)and SiC due to direct amorphization.In addition,the amorphous SiO_(2)film undergoes densification and then ruptures with the indentation depth increases.The modulus and hardness increase with increasing the indentation depth at the initial stage but will reach their stable values equivalent to monocrystalline 6 H-SiC.
文摘Highly porous 316L stainless steel parts were produced by using a powder metallurgy process, which includes the selective laser sintering(SLS) and traditional sintering. Porous 316L stainless steel suitable for medical applications was successfully fabricated in the porosity range of 40%-50% (volume fraction) by controlling the SLS parameters and sintering behaviour. The porosity of the sintered compacts was investigated as a function of the SLS parameters and the furnace cycle. Compressive stress and elastic modulus of the 316L stainless steel material were determined. The compressive strength was found to be ranging from 21 to 32 MPa and corresponding elastic modulus ranging from 26 to 43 GPa. The present parts are promising for biomedical applications since the optimal porosity of implant materials for ingrowths of new-bone tissues is in the range of 20%-59% (volume fraction) and mechanical properties are matching with human bone.
文摘Lattice structures are three-dimensional structures composed of repeated geometrical shapes with multiple interconnected nodes,providing high strength-to-weight ratios,customizable properties,and efficient use of materials.A smart use of materials leads to reduced fuel consumption and lower operating costs,making them highly desirable for aircraft manufacturers.Furthermore,the customizable properties of lattice structures allow for tailoring to specific design requirements,leading to improved performance and safety for aircraft.These advantages make lattice structures an important focus for research and development in the aviation industry.This paper presents an experimental evaluation of the mechanical compression properties of lattice trusses made with Ti6Al4V,designed for use in an anti-ice system.The truss structures were manufactured using additive manufacturing techniques and tested under compressive loads to determine mechanical properties.Results showed that lattice trusses exhibited high levels of compressive strength,making them suitable for use in applications where mechanical resistance and durability are critical,such as in anti-ice systems.We also highlight the potential of additive manufacturing techniques for the fabrication of lattice trusses with tailored mechanical properties.The study provides valuable insights into the mechanical behavior of Ti6Al4V lattice trusses and their potential applications in anti-ice systems,as well as other areas where high strength-to-weight ratios are required.The results of this research contribute to the development of lightweight,efficient,and durable anti-ice systems for use in aviation and other industries.
基金supported by the National Natu-ral Science Foundation of China(51875241)National Key R&D Program of China(2018YFF010124)+1 种基金Jilin Province Key R&D Plan Project(20190302078GX,YDZJ202101ZYTS129)Graduate In-novation Fund of Jilin University(101832020CX098).
文摘Here,a systematic investigation was made on the interphase strengthening effects induced superior me-chanical performances of multiphase high-entropy alloys(HEAs)at micro/nano-scale,compared with sin-gle phase HEAs.A pillar compression test under a scanning electron microscope(SEM)was performed on the individual face centered cubic(FCC),body centered cubic(BCC),and mixed-phases with different di-ameters in a Fe_(24)Co_(25)Ni_(24)Cr_(23)Al_(4)HEA using focused ion beam(FIB)milling and a nanoindenter equipped with a flat punch.The stress-strain response of pillar underneath the indenter was selected to explore the diameter/phase-dependent size effect,the periodically fluctuation of local stress,and strain hardening.It was revealed that the pillars at the interphase exhibited significantly higher strength,compared with the FCC and BCC pillars.An experiment also verified the coincident mechanical size effects independent with the type of phases.The stress responses in the mixed-phase pillars manifested as a distinct transition from the dramatic drop to the minor fluctuation during the post-yield stages with the increasing strain,indicating the propagation of Al-Ni enriched solid solution phase(BCC1)under compression.Except the BCC1 phase,numerous dislocations were observed in the post-deformed pillars,particularly serving as the major source to enhance the strain hardening of BCC pillars.
