The performances of magnesium alloys remain insufficient to further enhance the application potential of ultralight magnesium alloys.In this work,a Mg-8Li-3Y-2Zn alloy was prepared through vacuum melting and subsequent...The performances of magnesium alloys remain insufficient to further enhance the application potential of ultralight magnesium alloys.In this work,a Mg-8Li-3Y-2Zn alloy was prepared through vacuum melting and subsequent heat treatment at 300,450,and 500°C.The material properties of the resulting samples were assessed through microstructural observation,tensile testing,electrical conductivity measurements,and electromagnetic shielding effectiveness(EMI-SE)testing.The influence of the Mg-8Li-3Y-2Zn alloy microstructure on its mechanical and electromagnetic shielding properties in different states was investigated.It was found that the as-cast alloy containsα-Mg,β-Li,Mg_(3)Zn_(3)Y_(2),and Mg_(12)ZnY phases.Following heat treatment at 500℃(HT500),the blockα-Mg phase transformedfine needle-shapes,its tensile strength increased to 263.7 MPa,and its elongation reached 45.3%.The mechanical properties of the alloy were significantly improved by the synergistic effects imparted by the needle-shapedα-Mg phase,solid solution strengthening,and precipitation strengthening.The addition of Y and Zn improved the EMI-SE of Mg-8Li-1Zn alloy,wherein the HT500 sample exhibits the highest SE,maintaining a value of 106.7–76.9 dB in the frequency range of 30–4500 MHz;this performance has rarely been reported for electromagnetically shielded alloys.This effect was mainly attributed to the multiple reflections of electromagnetic waves caused by the severe impedance mismatch of the abundant phase boundaries,which were in turn provided by the dual-phase(α/β)and secondary phases.Furthermore,the presence of nano-precipitation was also believed to enhance the absorption of electromagnetic waves.展开更多
Reinforcing metal matrix composites(MMCs)with nanophases of distinct characteristics is an effective strategy for utilizing their individual advantages and achieving superior properties of the composite.In this study,...Reinforcing metal matrix composites(MMCs)with nanophases of distinct characteristics is an effective strategy for utilizing their individual advantages and achieving superior properties of the composite.In this study,a combination of molecular level mixing(MLM),segment ball milling(SBM),and in-situ solid-phase reaction was employed to fabricate Cu matrix composites(TiC-CNT/Cu)reinforced with TiC decorated CNT(TiC@CNT)and in-situ nanoscale TiC particles.The HRTEM results revealed the epitaxial growth of interfacial TiC on the surface of CNT(i.e.,CNT(0002)//TiC(200),and the formation of a semi-coherent interface between TiC and Cu matrix,which can effectively enhance the interfacial bonding strength and optimize load transfer efficiency of CNT.The independent in-situ TiC nanoparticles got into the grain interior through grain boundary migration,thereby significantly enhancing both strain hardening capacity and strength of the composite by fully utilizing the Orowan strengthening mechanism.Moreover,the enhanced bonding strength of the interface can also effectively suppress crack initiation and propagation,thereby improving the fracture toughness of the composite.The TiC-CNT/Cu composite with 1.2 vol.%CNT exhibited a tensile strength of 372 MPa,achieving a super high strengthening efficiency of 270,while simultaneously maintaining a remarkable ductility of 21.2%.Furthermore,the impact toughness of the TiC-CNT/Cu composite exhibited a significant enhancement of 70.7%compared to that of the CNT/Cu composite,reaching an impressive value of 251 kJ/m^(2),thereby demonstrating exceptional fracture toughness.Fully exploiting the synergistic strengthening effect of different nanophases can be an effective way to improve the comprehensive properties of MMCs.展开更多
Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research...Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research used chemical co-precipitation within an automated experimental device to synthesize RETaO_(4)(RE=Nd,Sm,Gd,Ho,Er)powders.The device automatically monitored and controlled the solutions'pH,improving the chemical co-precipitation efficiency.The crystal structure and microstructure of the RETaO_(4)powders can be controlled by changing the annealing temperature,and the materials undergo an m'-m phase transition.The m'-RETaO_(4)powders exhibit nano-size grains,while m-RETaO_(4)powders evince micron-size grains,altered by the annealing temperatures.A simultaneous thermal analysis es-timates the reversive ferroelastic tetragonal-monoclinic phase transition temperatures.Overall,this research focuses on the synthesis,crystal structures,microstructures,and phase transition of the fabricated RETaO_(4)powders.展开更多
Thermal and mechanical properties of yttrium tantalate(YTaO_(4)),a top coat ceramic of thermal barrier coatings(TBCs)for aeroengines,are enhanced by synthesizing Y_(1-x)Ta_(1-x)M_(2x)O_(4)(M=Ti,Zr,Hf;x=0.06,0.12,0.18,...Thermal and mechanical properties of yttrium tantalate(YTaO_(4)),a top coat ceramic of thermal barrier coatings(TBCs)for aeroengines,are enhanced by synthesizing Y_(1-x)Ta_(1-x)M_(2x)O_(4)(M=Ti,Zr,Hf;x=0.06,0.12,0.18,0.24)medium-entropy ceramics(MECs)using a two-step sintering method.In addition,the thermal conductivity,thermal expansion coefficients(TECs),and fracture toughness of MECs were investigated.An X-ray diffraction study revealed that the Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs were monoclinic,and the Ti,Zr,and Hf doping elements replaced Y and Ta.The variations in atomic weights and ionic radii led to disturbed atomic arrangements and severe lattice distortions,resulting in improving the phonon scattering and reduced thermal conductivity,with Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs(x=0.24)exhibiting the lowest thermal conductivity of 1.23 W·m^(-1)·K^(-1)at 900℃.The introduction of MO_(2) increased the configurational entropy and weakened the ionic bonding energy,obtaining high TECs(10.4×10^(-6)K^(-1)at 1400℃).The reduction in the monoclinic angle β lowered the ferroelastic domain inversion energy barrier.Moreover,microcracks and crack extension toughening endowed Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs(x=0.24)with the highest fracture toughness of(4.1±0.5)MPa·m~(1/2).The simultaneous improvement of the thermal and mechanical properties of the MO_(2)(M=Ti,Zr,Hf)co-doped YTaO_(4) MECs can be extended to other materials.展开更多
Bi_(2)S_(3)is composed of inexpensive and environ-mental friendliness elements,which has received extensive interests and been investigated as a promising mid-tempera-ture thermoelectric material for years.Even pure B...Bi_(2)S_(3)is composed of inexpensive and environ-mental friendliness elements,which has received extensive interests and been investigated as a promising mid-tempera-ture thermoelectric material for years.Even pure Bi_(2)S_(3)pos-sesses a high Seebeck coefficient and low thermal conductivity,its low electrical conductivity leads to a lowfigure of merit(ZT)value.In this work,Bi_(2)S_(3)fabricated by solid-state melting combined with spark plasma sintering can significantly enhance the thermoelectric performance via introducing small amounts of Cu and BiCl_(3).Cu interstitial doping and Cl substitution on S site result in a large increase in electrical conductivity.Additionally,the enhanced phonon scattering is derived from the point defects caused by element doping,the grain boundaries,and the small amount of sec-ondary phase,which leads to the low thermal conductivity.Finally,a high ZT value of 0.7 is obtained at 773 K and reaches a large average ZT of 0.36 in the temperature range from room temperature(RT)to 773 K for the Cu-interstitial-doped and BiCl_(3)-alloyed(Cu_(0.01)Bi_(2)S_(3)+0.175 mol%BiCl_(3))sample.Furthermore,the mechanical properties of the Cu_(0.01)Bi_(2)S_(3)+0.175 mol%BiCl_(3)sample are lower than those of other Bi_(2)S_(3)samples,which stem from the weak chemical bonding strength.展开更多
Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymeriza...Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.展开更多
The group Ⅳ–Ⅵ semiconductor,SnSe,is abundant on the earth and is a promising thermoelectric(TE)material due to its low thermal conductivity.However,the p-type SnSe polycrystals have low electrical conductivities du...The group Ⅳ–Ⅵ semiconductor,SnSe,is abundant on the earth and is a promising thermoelectric(TE)material due to its low thermal conductivity.However,the p-type SnSe polycrystals have low electrical conductivities due to their low carrier concentration,significantly limiting their further applications.This study introduced the argyrodite-type Ag_(9)GaSe_(6) compound into the SnSe matrix to effectively increase the hole carrier concentration,increasing the electrical conductivity.A high electrical conductivity of 50.5 S cm^(−1) was obtained for the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample at 323 K.Due to the increased electrical conductivity,the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample had an average power factor(PFave)value of~410μW m^(-1) K^(-2) in the 323–823 K temperature range,a nearly four times enhancement compared to the undoped SnSe sample.Additionally,the thermal conductivity slightly increased due to the introduction of the Ag_(9)GaSe_(6) compound.However,the electrical transport properties were significantly enhanced,making up for the improvement in thermal conductivity.Consequently,the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample obtained a peak thermoelectric figure of merit ZT value of~1.2 at 823 K and a ZT_(ave) value of 0.58 in the 323–823 K temperature range.The proposed strategy improved the ZT and ZT_(ave) values of SnSe-based TE materials at room temperature and provided a systematic strategy for modifying SnSe-based TE materials.Moreover,the thermoelectric properties of SnSe can be effectively improved by introducing the Ag_(9)GaSe_(6) compound for doping,and waste heat power generation can be effectively carried out in the middle temperature region.展开更多
A novel approach of decorating graphene surface with graphene quantum dots(abbreviated as GQDs@Gr)was presented to achieve superior tribological properties in Gr/Cu composites.The prepared GQDs@Gr hybrid reinforcement...A novel approach of decorating graphene surface with graphene quantum dots(abbreviated as GQDs@Gr)was presented to achieve superior tribological properties in Gr/Cu composites.The prepared GQDs@Gr hybrid reinforcement possessed superior dispersion and had achieved strong interface bonding with Cu matrix.GQDs@Gr/Cu composite showed a good combination of wear resistance and electrical conductivity due to the synergistic effect of GQDs and Gr.Specifically,the coefficient of friction(COF)was reduced to 0.3,the wear rate(WR)was 2.13×10^(-5) mm^(3)·N^(−1)·m^(−1)(only a quarter of pure copper),and maintained the electrical conductivity of 96.5%IACS(international annealed copper standard).As a result,delamination,fracture,and plow furrows on the wear surface of Gr/Cu composite indicate that fatigue and abrasive adhesive wear are the main wear mechanisms.Wear surface lubrication film and strong interface bonding ensure better comprehensive performance of GQDs@Gr/Cu composite.展开更多
The deep potential(DP)is an innovative approach based on deep learning that uses ab initio calculation data derived from density functional theory(DFT),to create high-accuracy potential functions for various materials...The deep potential(DP)is an innovative approach based on deep learning that uses ab initio calculation data derived from density functional theory(DFT),to create high-accuracy potential functions for various materials.Platinum(Pt)is a rare metal with significant potential in energy and catalytic applications,However,there are challenges in accurately capturing its physical properties due to high experimental costs and the limitations of traditional empirical methods.This study employs deep learning methods to construct high-precision potential models for single-element systems of Pt and validates their predictive performance in complex environments.The newly developed DP is highly consistent with DFT results in predicting the stable phases,lattice constants,surface energies,and phonons dispersion relations of Pt,demonstrating outstanding quantum-level accuracy.Additionally,the complex phase transitions and domain formations of Pt are extensively and quantitatively analyzed.Molecular dynamic simulations utilizing the DP approach show that Pt’s face-centered cubic(FCC)structure undergoes a phase transition from solid to liquid at its melting point of 1986 K,this is in close agreement with the experimental value of 2041.5 K.Increased temperature enhances the diffusion of Pt atoms,with a self-diffusion coefficient of 1.17×10-11 m2/s at the melting point,comparable to that of other FCC metals.This result can be utilized for the precise analysis of the fundamental properties of the rare metal Pt at the microscopic scale,and it facilitates the development of binary or multi-component deep potential models that include Pt.展开更多
The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting(SLM)technology exhibits a“bimodal microstructure”,resulting in significant non-uniform deformation during thermal deformation.This stud...The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting(SLM)technology exhibits a“bimodal microstructure”,resulting in significant non-uniform deformation during thermal deformation.This study investigates the flow behavior of SLM-processed AlMgScZr aluminum alloy utilizing the Gleeble-1500D thermal simulation machine.The true stress-strain curves were amended based on the friction theory.Through determining the Zener-Hollomon parameters,the correlation between flow stress,deformation temperature,and strain rate during the high-temperature thermoplastic deformation of SLM-processed AlMgScZr aluminum alloy with a“bimodal microstructure”was established.In addition,the microstructural evolution during thermal deformation was analyzed.The results indicated that the predicted flow stress values obtained from the Arrhenius constitutive equation with coupled correction of thermal deformation parameters closely matched the experimental values.The correlation coefficient and the average absolute relative error of the corrected model were 0.999 and 2.766%,respectively,accurately predicting the thermoplastic deformation behavior of SLM-processed high-strength aluminum alloy with a“bimodal microstructure”.Furthermore,hot processing maps at different strains were established,identifying stable and unstable regions under different deformation conditions.Microstructural observations revealed different thermal deformation mechanisms under various deformation temperatures.Specifically,dynamic recrystallization characteristics dominated the microstructure at lower temperatures(300-360℃),while dynamic recovery was dominant at higher temperatures(390-500℃).展开更多
This study systematically investigated the microstructure,mechanical properties,and corrosion behavior of an extruded Zn-0.2Mg alloy processed by multi-directional forging(MDF)at 100℃.The mean grain size was remarkab...This study systematically investigated the microstructure,mechanical properties,and corrosion behavior of an extruded Zn-0.2Mg alloy processed by multi-directional forging(MDF)at 100℃.The mean grain size was remarkably decreased from 17.2±0.5µm to 1.9±0.3µm,and 84.4%of the microstructure was occupied by grains of below 1µm in size after applying three MDF passes.Electron backscattered difraction examinations revealed that continuous dynamic recrystallization,progressive lattice rotation,and particle-stimulated nucleation mechanisms were recognized as contributing to microstructural evolution.Furthermore,transmission electron microscopy results showed that nanoparticles of Mg/Zn dynamically formed under high strain MDF,while the initial extrusion fber texture was altered to be<0001>parallel to the fnal forging axis.A synergistic efect of grain refnement,texture evolution,second-phase precipitates,and dislocation strengthening resulted in an increased ultimate tensile strength of 232±5 MPa after three MDF passes.However,this was accompanied by a reduction in the elongation(8±2.1%).Additionally,a high corrosion rate of 0.59 mm/year was measured for the experimental alloy fabricated by 3 MDF passes.In agreement with the latter,electrochemical impedance spectroscopy results indicated that the grain refnement improved the passivation kinetics of the oxide layer.展开更多
Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO...Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO)through an in-situ interface reaction strategy,achieving simultaneous improvement in the strength,ductility,and electromagnetic shielding performance of the composite.The magnetic component is generated by the in-situ reaction of Fe_(2)O_(3)nanoparticles encapsulated on RGO with the Mg matrix.The superior strength-ductility synergy originates from layered heterostructure,which actives non-basal dislocations and enables a stable microcrackmultiplication.The heterogeneous layered structure strengthens the multi-level reflection of electromagnetic wave(EMW)inside the composite.The in-situ interfacial reaction introduces abundant of heterogeneous interfaces into the composites,which improves the interfacial polarization loss ability of the composites.The magnetic RGO layer can provide shape anisotropy that breaks the Snoek limit,thus improving the magnetic loss ability of composite in high-frequency electromagnetic fields.The synergistic action of multiple EMW loss mechanisms improves the electromagnetic shielding performance of composite.The current study emphasizes the influence of interface structure on the mechanical and functional properties of composites,and presents a promising approach for the development of structure/functional integrated composites with enhanced properties.展开更多
Over the years,the high magnetic induction of industrial Mn-added electrical steel is assumed to be the enhancement of{100}texture derived from its austenite-ferrite phase transformation during hot rolling(phase trans...Over the years,the high magnetic induction of industrial Mn-added electrical steel is assumed to be the enhancement of{100}texture derived from its austenite-ferrite phase transformation during hot rolling(phase transformation(PT)method).However,it is still undetermined without straightforward experimental evidence.The reason for{100}texture improvement of Mn-added electrical steel is experimentally confirmed due to the recrystallization induced by the austenite-ferrite phase transformation during hot rolling.Moreover,a more promising methodology to further improve{100}texture and formability of hot-rolled electrical steel is promoted by the control of hot rolling deformation condition(shear deformation(SD)method).The results show that the nucleation mechanisms of{100}oriented recrystallized grains are different in the samples by SD and PT methods,which are in-depth shear deformation and austenite-ferrite phase transformation,respectively.In this case,coarse{100}oriented recrystallized grains and low residual stress are obtained in the sample by SD method,which is responsible for its superior{100}texture and formability.In contrast,the sample by PT method forms fine recrystallized grains with random orientations and accumulates severe residual stress.展开更多
Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utiliz...Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utilize the differences in structure and chemical reactivity between them and their metallic counterparts.These differences are too small to greatly improve their purity and reproducibility.Here we report an energy engineering strategy to expand the etching energy barrier difference of SWCNTs with different conductivities.In addition to density functional theory calculations on the energy barrier change,hydrogenation of single-wall carbon nanotubes(SWCNTs)by hydrogen plasma treatment and reversible dehydrogenation by annealing were realized experimentally.The structure-dependent hydrogenation and following selective oxidative etching of SWCNTs were demonstrated.As a result,horizontally aligned s-SWCNT arrays with high purity were obtained.展开更多
A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on t...A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on the microstructure,mechanical properties,and electromagnetic interference(EMI)shielding effectiveness(SE)of the alloy,specifically across three distinct layers within the stir zone(SZ):Top,Middle,and Bottom.The results reveal that the Mg_(12)YZn long-period stacking ordered(LPSO)phase is the predominant structure,undergoing significant grain refinement.The grain size is drastically reduced from 1.5 mm in the as-cast state to 12.6μm,10.0μm,and 7.1μm in the Top,Middle,and Bottom,respectively.This grain refinement and fragmentation of the LPSO phase into nanoscale particles result in a substantial enhancement of mechanical properties.The ultimate tensile strength(UTS)reached 358.2 MPa with an elongation(EL)of 15.1%,reflecting a 344% increase in strength and a 733% improvement in ductility compared to the as-cast material.Simultaneously,the EMI SE was maintained between 70 and 110.4 dB over a broad frequency range(30-4500 MHz).Despite the nanoscale LPSO particles contributing minimally to EMI shielding,the lamellar LPSO structure demonstrated excellent performance through multiple electromagnetic wave reflections within the matrix.These findings underscore the dual benefits of FSP in improving both mechanical strength and electromagnetic shielding effectiveness,positioning this Mg_(98.5)Zn_(0.5)Y alloy for advanced applications in the electronics and telecommunications sectors.展开更多
In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.Th...In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.The annealing at 300℃ for 2 h did not change the grain size significantly;however,a slight growth of Mg_(2)Ca precipitates was observed.When the annealing temperature increased up to 400℃ for 2 h,full recrystallization of the alloy occurred;the grains and precipitates grew noticeably.Those changes were responsible for decreasing the corrosion and the tribocorrosion resistance of the alloy.Due to lowered resistance to the corrosion medium,the cell viability was also reduced.Although MG63 cells on the annealed specimens developed filopodia,cell-to-cell communication was not observed.展开更多
Quantitative analysis of aluminum-silicon(Al-Si)alloy microstructure is crucial for evaluating and controlling alloy performance.Conventional analysis methods rely on manual segmentation,which is inefficient and subje...Quantitative analysis of aluminum-silicon(Al-Si)alloy microstructure is crucial for evaluating and controlling alloy performance.Conventional analysis methods rely on manual segmentation,which is inefficient and subjective,while fully supervised deep learning approaches require extensive and expensive pixel-level annotated data.Furthermore,existing semi-supervised methods still face challenges in handling the adhesion of adjacent primary silicon particles and effectively utilizing consistency in unlabeled data.To address these issues,this paper proposes a novel semi-supervised framework for Al-Si alloy microstructure image segmentation.First,we introduce a Rotational Uncertainty Correction Strategy(RUCS).This strategy employs multi-angle rotational perturbations andMonte Carlo sampling to assess prediction consistency,generating a pixel-wise confidence weight map.By integrating this map into the loss function,the model dynamically focuses on high-confidence regions,thereby improving generalization ability while reducing manual annotation pressure.Second,we design a Boundary EnhancementModule(BEM)to strengthen boundary feature extraction through erosion difference and multi-scale dilated convolutions.This module guides the model to focus on the boundary regions of adjacent particles,effectively resolving particle adhesion and improving segmentation accuracy.Systematic experiments were conducted on the Aluminum-Silicon Alloy Microstructure Dataset(ASAD).Results indicate that the proposed method performs exceptionally well with scarce labeled data.Specifically,using only 5%labeled data,our method improves the Jaccard index and Adjusted Rand Index(ARI)by 2.84 and 1.57 percentage points,respectively,and reduces the Variation of Information(VI)by 8.65 compared to stateof-the-art semi-supervised models,approaching the performance levels of 10%labeled data.These results demonstrate that the proposed method significantly enhances the accuracy and robustness of quantitative microstructure analysis while reducing annotation costs.展开更多
To exploit the combined strengthening effects of nanotwins and carbon nanotubes(CNTs)in Cu matrix composites,the nanotwins with a width ranging from 3 to 30 nm were incorporated into the CNTs-reinforced Cu matrix comp...To exploit the combined strengthening effects of nanotwins and carbon nanotubes(CNTs)in Cu matrix composites,the nanotwins with a width ranging from 3 to 30 nm were incorporated into the CNTs-reinforced Cu matrix composites using cryogenic rolling and optimizing the initial particle size of the raw Cu powders.The formation of nanotwins in the Cu matrix composite reinforced by only 0.2 wt.%CNTs is accompanied by the increased dislocation density and refined Cu grain size,resulting in much better strength−ductility synergy than the referenced composite without significant nanotwins formation.The analysis of strengthening and toughening mechanisms demonstrates that the strength increment mainly derives from grain refinement strengthening,dislocation strengthening,and nanotwin strengthening.The strength increment from the contribution of the nanotwins accounts for 19.9%of the overall strength increment for the composite.Meanwhile,the retention of good tensile ductility can be reasonably explained by the increased dislocation accommodation ability due to the formed nanotwins and the decreased induced dislocation proliferation.展开更多
Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on ...Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.展开更多
基金supported by the National Natural Sci-ence Foundation of China[No.51564032]Yunnan Provin-cial Department of Education Science Research Fund Project[KKPH202132005]the Analysis and Testing Founda-tion of Kunming University of Science and Technology[2022M20212130086].
文摘The performances of magnesium alloys remain insufficient to further enhance the application potential of ultralight magnesium alloys.In this work,a Mg-8Li-3Y-2Zn alloy was prepared through vacuum melting and subsequent heat treatment at 300,450,and 500°C.The material properties of the resulting samples were assessed through microstructural observation,tensile testing,electrical conductivity measurements,and electromagnetic shielding effectiveness(EMI-SE)testing.The influence of the Mg-8Li-3Y-2Zn alloy microstructure on its mechanical and electromagnetic shielding properties in different states was investigated.It was found that the as-cast alloy containsα-Mg,β-Li,Mg_(3)Zn_(3)Y_(2),and Mg_(12)ZnY phases.Following heat treatment at 500℃(HT500),the blockα-Mg phase transformedfine needle-shapes,its tensile strength increased to 263.7 MPa,and its elongation reached 45.3%.The mechanical properties of the alloy were significantly improved by the synergistic effects imparted by the needle-shapedα-Mg phase,solid solution strengthening,and precipitation strengthening.The addition of Y and Zn improved the EMI-SE of Mg-8Li-1Zn alloy,wherein the HT500 sample exhibits the highest SE,maintaining a value of 106.7–76.9 dB in the frequency range of 30–4500 MHz;this performance has rarely been reported for electromagnetically shielded alloys.This effect was mainly attributed to the multiple reflections of electromagnetic waves caused by the severe impedance mismatch of the abundant phase boundaries,which were in turn provided by the dual-phase(α/β)and secondary phases.Furthermore,the presence of nano-precipitation was also believed to enhance the absorption of electromagnetic waves.
基金financially supported by the National Natural Science Foundation of China(No.52371136)the Yunnan Provincial Science and Technology Department(No.202202AG050004).
文摘Reinforcing metal matrix composites(MMCs)with nanophases of distinct characteristics is an effective strategy for utilizing their individual advantages and achieving superior properties of the composite.In this study,a combination of molecular level mixing(MLM),segment ball milling(SBM),and in-situ solid-phase reaction was employed to fabricate Cu matrix composites(TiC-CNT/Cu)reinforced with TiC decorated CNT(TiC@CNT)and in-situ nanoscale TiC particles.The HRTEM results revealed the epitaxial growth of interfacial TiC on the surface of CNT(i.e.,CNT(0002)//TiC(200),and the formation of a semi-coherent interface between TiC and Cu matrix,which can effectively enhance the interfacial bonding strength and optimize load transfer efficiency of CNT.The independent in-situ TiC nanoparticles got into the grain interior through grain boundary migration,thereby significantly enhancing both strain hardening capacity and strength of the composite by fully utilizing the Orowan strengthening mechanism.Moreover,the enhanced bonding strength of the interface can also effectively suppress crack initiation and propagation,thereby improving the fracture toughness of the composite.The TiC-CNT/Cu composite with 1.2 vol.%CNT exhibited a tensile strength of 372 MPa,achieving a super high strengthening efficiency of 270,while simultaneously maintaining a remarkable ductility of 21.2%.Furthermore,the impact toughness of the TiC-CNT/Cu composite exhibited a significant enhancement of 70.7%compared to that of the CNT/Cu composite,reaching an impressive value of 251 kJ/m^(2),thereby demonstrating exceptional fracture toughness.Fully exploiting the synergistic strengthening effect of different nanophases can be an effective way to improve the comprehensive properties of MMCs.
基金the Rare and Precious Metals Material Genetic Engineering Project of Yunnan Province(202102AB080019-1)National Key Research and Development Program of China(2022YFB3708600)the National Natural Science Foundation of China(91960103).
文摘Ferroelastic rare earth tantalates(RETaO_(4))are widely researched as the next-generation thermal barrier coatings(TBCs),and RETaO_(4)powders are hugely significant for synthesizing their coatings.The current research used chemical co-precipitation within an automated experimental device to synthesize RETaO_(4)(RE=Nd,Sm,Gd,Ho,Er)powders.The device automatically monitored and controlled the solutions'pH,improving the chemical co-precipitation efficiency.The crystal structure and microstructure of the RETaO_(4)powders can be controlled by changing the annealing temperature,and the materials undergo an m'-m phase transition.The m'-RETaO_(4)powders exhibit nano-size grains,while m-RETaO_(4)powders evince micron-size grains,altered by the annealing temperatures.A simultaneous thermal analysis es-timates the reversive ferroelastic tetragonal-monoclinic phase transition temperatures.Overall,this research focuses on the synthesis,crystal structures,microstructures,and phase transition of the fabricated RETaO_(4)powders.
文摘Thermal and mechanical properties of yttrium tantalate(YTaO_(4)),a top coat ceramic of thermal barrier coatings(TBCs)for aeroengines,are enhanced by synthesizing Y_(1-x)Ta_(1-x)M_(2x)O_(4)(M=Ti,Zr,Hf;x=0.06,0.12,0.18,0.24)medium-entropy ceramics(MECs)using a two-step sintering method.In addition,the thermal conductivity,thermal expansion coefficients(TECs),and fracture toughness of MECs were investigated.An X-ray diffraction study revealed that the Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs were monoclinic,and the Ti,Zr,and Hf doping elements replaced Y and Ta.The variations in atomic weights and ionic radii led to disturbed atomic arrangements and severe lattice distortions,resulting in improving the phonon scattering and reduced thermal conductivity,with Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs(x=0.24)exhibiting the lowest thermal conductivity of 1.23 W·m^(-1)·K^(-1)at 900℃.The introduction of MO_(2) increased the configurational entropy and weakened the ionic bonding energy,obtaining high TECs(10.4×10^(-6)K^(-1)at 1400℃).The reduction in the monoclinic angle β lowered the ferroelastic domain inversion energy barrier.Moreover,microcracks and crack extension toughening endowed Y_(1-x)Ta_(1-x)M_(2x)O_(4) MECs(x=0.24)with the highest fracture toughness of(4.1±0.5)MPa·m~(1/2).The simultaneous improvement of the thermal and mechanical properties of the MO_(2)(M=Ti,Zr,Hf)co-doped YTaO_(4) MECs can be extended to other materials.
基金financially supported by the National Natural Science Foundation of China (No. 11764025)the Academician (Expert) Workstation of Yunnan Province Program (No. 202005AF150010)Yunnan Provincial Natural Science Key Fund (No. 202101AS070015)。
文摘Bi_(2)S_(3)is composed of inexpensive and environ-mental friendliness elements,which has received extensive interests and been investigated as a promising mid-tempera-ture thermoelectric material for years.Even pure Bi_(2)S_(3)pos-sesses a high Seebeck coefficient and low thermal conductivity,its low electrical conductivity leads to a lowfigure of merit(ZT)value.In this work,Bi_(2)S_(3)fabricated by solid-state melting combined with spark plasma sintering can significantly enhance the thermoelectric performance via introducing small amounts of Cu and BiCl_(3).Cu interstitial doping and Cl substitution on S site result in a large increase in electrical conductivity.Additionally,the enhanced phonon scattering is derived from the point defects caused by element doping,the grain boundaries,and the small amount of sec-ondary phase,which leads to the low thermal conductivity.Finally,a high ZT value of 0.7 is obtained at 773 K and reaches a large average ZT of 0.36 in the temperature range from room temperature(RT)to 773 K for the Cu-interstitial-doped and BiCl_(3)-alloyed(Cu_(0.01)Bi_(2)S_(3)+0.175 mol%BiCl_(3))sample.Furthermore,the mechanical properties of the Cu_(0.01)Bi_(2)S_(3)+0.175 mol%BiCl_(3)sample are lower than those of other Bi_(2)S_(3)samples,which stem from the weak chemical bonding strength.
基金financially supported by the National Key R&D Program of China(No.2022YFC2805103)the National Natural Science Foundation of China(Nos.52022031 and 52263001)the Foundation from Qinghai Science and Technology Department(No.2022-ZJ-944Q)。
文摘Incorporation of acetal groups in the backbone is a potent strategy to create polymers that are cleavable or degradable under acidic conditions.We report here an in-depth study on the ring-closing-opening copolymerization of o-phthalaldehyde(OPA)and epoxide using Lewis pair type two-component organocatalysts for producing acetal-functionalized polyether and polyurethane.Notably,triethylborane as the Lewis acid,in comparison with tri(n-butyl)borane,more effectively enhances the polymerization activity by mitigating borane-induced reduction of the aldehyde group into extra initiating(borinic ester)species.Density functional theory(DFT)calculations present comparable energy barriers of OPA-epoxide cross-propagation and epoxide self-propagation,which is consistent with the experimental finding that an alternating-rich copolymer comprising mostly OPA-epoxide units but also epoxide-epoxide linkages is produced.In particular,when epoxide is added in a large excess,the product becomes a polyether containing acetal functionalities in the central part of the backbone and thus being convertible into polyurethane with refined acid degradability.
基金supported by the Outstanding Youth Fund of Yunnan Province(Grant No.202201AV070005)the National Natural Science Foundation of China(Grant No.52162029)+1 种基金the National Key R&D Program of China(Grant No.2022YFF0503804)the Yunnan Science and Technology Program(202401AT070403).
文摘The group Ⅳ–Ⅵ semiconductor,SnSe,is abundant on the earth and is a promising thermoelectric(TE)material due to its low thermal conductivity.However,the p-type SnSe polycrystals have low electrical conductivities due to their low carrier concentration,significantly limiting their further applications.This study introduced the argyrodite-type Ag_(9)GaSe_(6) compound into the SnSe matrix to effectively increase the hole carrier concentration,increasing the electrical conductivity.A high electrical conductivity of 50.5 S cm^(−1) was obtained for the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample at 323 K.Due to the increased electrical conductivity,the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample had an average power factor(PFave)value of~410μW m^(-1) K^(-2) in the 323–823 K temperature range,a nearly four times enhancement compared to the undoped SnSe sample.Additionally,the thermal conductivity slightly increased due to the introduction of the Ag_(9)GaSe_(6) compound.However,the electrical transport properties were significantly enhanced,making up for the improvement in thermal conductivity.Consequently,the SnSe+0.5 wt%Ag_(9)GaSe_(6) sample obtained a peak thermoelectric figure of merit ZT value of~1.2 at 823 K and a ZT_(ave) value of 0.58 in the 323–823 K temperature range.The proposed strategy improved the ZT and ZT_(ave) values of SnSe-based TE materials at room temperature and provided a systematic strategy for modifying SnSe-based TE materials.Moreover,the thermoelectric properties of SnSe can be effectively improved by introducing the Ag_(9)GaSe_(6) compound for doping,and waste heat power generation can be effectively carried out in the middle temperature region.
基金supported by Yunnan Fundamental Research Projects(No.202401CF070085)Yunnan Engineering Research Projects(No.2023-XMDJ-00617273)+1 种基金Industrial Support Plan Project of Gansu Provincial Education Department(No.2024CYZC-22)the National Natural Science Foundation of China(No.52064032).
文摘A novel approach of decorating graphene surface with graphene quantum dots(abbreviated as GQDs@Gr)was presented to achieve superior tribological properties in Gr/Cu composites.The prepared GQDs@Gr hybrid reinforcement possessed superior dispersion and had achieved strong interface bonding with Cu matrix.GQDs@Gr/Cu composite showed a good combination of wear resistance and electrical conductivity due to the synergistic effect of GQDs and Gr.Specifically,the coefficient of friction(COF)was reduced to 0.3,the wear rate(WR)was 2.13×10^(-5) mm^(3)·N^(−1)·m^(−1)(only a quarter of pure copper),and maintained the electrical conductivity of 96.5%IACS(international annealed copper standard).As a result,delamination,fracture,and plow furrows on the wear surface of Gr/Cu composite indicate that fatigue and abrasive adhesive wear are the main wear mechanisms.Wear surface lubrication film and strong interface bonding ensure better comprehensive performance of GQDs@Gr/Cu composite.
基金supported by the Kunming University of Science and Technology“Double First-Class”Joint Special Project(Grant No.202101BE070001-011)Yunnan Fundamental Research Projects(202201BE070001-008,202201AT070192)+5 种基金National Natural Science Foundation of China(52402077)Shaanxi Province Key R&D Program(2021ZDLGY11-08)Open Project of Shaanxi Laboratory(2021SXsyS01-05)Open Project of Yunnan Precious Metals Laboratory(YPML-2023050240)National Natural Science Foundation of China(Grant No.52462009)Yunnan Fundamental Research Projects(Grant Nos.202201AT070192,202101BE070001-011).
文摘The deep potential(DP)is an innovative approach based on deep learning that uses ab initio calculation data derived from density functional theory(DFT),to create high-accuracy potential functions for various materials.Platinum(Pt)is a rare metal with significant potential in energy and catalytic applications,However,there are challenges in accurately capturing its physical properties due to high experimental costs and the limitations of traditional empirical methods.This study employs deep learning methods to construct high-precision potential models for single-element systems of Pt and validates their predictive performance in complex environments.The newly developed DP is highly consistent with DFT results in predicting the stable phases,lattice constants,surface energies,and phonons dispersion relations of Pt,demonstrating outstanding quantum-level accuracy.Additionally,the complex phase transitions and domain formations of Pt are extensively and quantitatively analyzed.Molecular dynamic simulations utilizing the DP approach show that Pt’s face-centered cubic(FCC)structure undergoes a phase transition from solid to liquid at its melting point of 1986 K,this is in close agreement with the experimental value of 2041.5 K.Increased temperature enhances the diffusion of Pt atoms,with a self-diffusion coefficient of 1.17×10-11 m2/s at the melting point,comparable to that of other FCC metals.This result can be utilized for the precise analysis of the fundamental properties of the rare metal Pt at the microscopic scale,and it facilitates the development of binary or multi-component deep potential models that include Pt.
基金Project(22KJB430023)supported by the Natural Science Foundation for Colleges and Universities of Jiangsu Province,ChinaProject(1172922101)supported by the Youth Science and Technology Innovation Project of Jiangsu University of Science and Technology,China。
文摘The AlMgScZr high-strength aluminum alloy fabricated by selective laser melting(SLM)technology exhibits a“bimodal microstructure”,resulting in significant non-uniform deformation during thermal deformation.This study investigates the flow behavior of SLM-processed AlMgScZr aluminum alloy utilizing the Gleeble-1500D thermal simulation machine.The true stress-strain curves were amended based on the friction theory.Through determining the Zener-Hollomon parameters,the correlation between flow stress,deformation temperature,and strain rate during the high-temperature thermoplastic deformation of SLM-processed AlMgScZr aluminum alloy with a“bimodal microstructure”was established.In addition,the microstructural evolution during thermal deformation was analyzed.The results indicated that the predicted flow stress values obtained from the Arrhenius constitutive equation with coupled correction of thermal deformation parameters closely matched the experimental values.The correlation coefficient and the average absolute relative error of the corrected model were 0.999 and 2.766%,respectively,accurately predicting the thermoplastic deformation behavior of SLM-processed high-strength aluminum alloy with a“bimodal microstructure”.Furthermore,hot processing maps at different strains were established,identifying stable and unstable regions under different deformation conditions.Microstructural observations revealed different thermal deformation mechanisms under various deformation temperatures.Specifically,dynamic recrystallization characteristics dominated the microstructure at lower temperatures(300-360℃),while dynamic recovery was dominant at higher temperatures(390-500℃).
文摘This study systematically investigated the microstructure,mechanical properties,and corrosion behavior of an extruded Zn-0.2Mg alloy processed by multi-directional forging(MDF)at 100℃.The mean grain size was remarkably decreased from 17.2±0.5µm to 1.9±0.3µm,and 84.4%of the microstructure was occupied by grains of below 1µm in size after applying three MDF passes.Electron backscattered difraction examinations revealed that continuous dynamic recrystallization,progressive lattice rotation,and particle-stimulated nucleation mechanisms were recognized as contributing to microstructural evolution.Furthermore,transmission electron microscopy results showed that nanoparticles of Mg/Zn dynamically formed under high strain MDF,while the initial extrusion fber texture was altered to be<0001>parallel to the fnal forging axis.A synergistic efect of grain refnement,texture evolution,second-phase precipitates,and dislocation strengthening resulted in an increased ultimate tensile strength of 232±5 MPa after three MDF passes.However,this was accompanied by a reduction in the elongation(8±2.1%).Additionally,a high corrosion rate of 0.59 mm/year was measured for the experimental alloy fabricated by 3 MDF passes.In agreement with the latter,electrochemical impedance spectroscopy results indicated that the grain refnement improved the passivation kinetics of the oxide layer.
基金supported by Yunnan Major Scientific and Technological Projects(grant No 202202AG050004,202202AG050011)the National Natural Science Foundation of China(grant No 52061021)Yunnan Industrial Technology Innovation Talent Project.
文摘Many properties of Mg matrix composites are mutually incompatible,and even completely repel each other.Here,we constructed a magnetic layered component in Mg matrix composite reinforced with reduced graphene oxide(RGO)through an in-situ interface reaction strategy,achieving simultaneous improvement in the strength,ductility,and electromagnetic shielding performance of the composite.The magnetic component is generated by the in-situ reaction of Fe_(2)O_(3)nanoparticles encapsulated on RGO with the Mg matrix.The superior strength-ductility synergy originates from layered heterostructure,which actives non-basal dislocations and enables a stable microcrackmultiplication.The heterogeneous layered structure strengthens the multi-level reflection of electromagnetic wave(EMW)inside the composite.The in-situ interfacial reaction introduces abundant of heterogeneous interfaces into the composites,which improves the interfacial polarization loss ability of the composites.The magnetic RGO layer can provide shape anisotropy that breaks the Snoek limit,thus improving the magnetic loss ability of composite in high-frequency electromagnetic fields.The synergistic action of multiple EMW loss mechanisms improves the electromagnetic shielding performance of composite.The current study emphasizes the influence of interface structure on the mechanical and functional properties of composites,and presents a promising approach for the development of structure/functional integrated composites with enhanced properties.
基金supports from the National Natural Science Foundation of China(NSFC)(Nos.51901091 and 52374316)the Yunnan Science and Technology Program(Nos.202401AT070403 and 202305AF150014).
文摘Over the years,the high magnetic induction of industrial Mn-added electrical steel is assumed to be the enhancement of{100}texture derived from its austenite-ferrite phase transformation during hot rolling(phase transformation(PT)method).However,it is still undetermined without straightforward experimental evidence.The reason for{100}texture improvement of Mn-added electrical steel is experimentally confirmed due to the recrystallization induced by the austenite-ferrite phase transformation during hot rolling.Moreover,a more promising methodology to further improve{100}texture and formability of hot-rolled electrical steel is promoted by the control of hot rolling deformation condition(shear deformation(SD)method).The results show that the nucleation mechanisms of{100}oriented recrystallized grains are different in the samples by SD and PT methods,which are in-depth shear deformation and austenite-ferrite phase transformation,respectively.In this case,coarse{100}oriented recrystallized grains and low residual stress are obtained in the sample by SD method,which is responsible for its superior{100}texture and formability.In contrast,the sample by PT method forms fine recrystallized grains with random orientations and accumulates severe residual stress.
基金supported by the National Natural Science Foundation of China(Nos.52130209,51927803,52188101,52372054,and 22003074)the National Key R&D Program of China(No.2022YFA1203302)+2 种基金Guangdong Provincial Key Laboratory Program of the Guangdong Science and Technology Department(No.2021B1212040001)the Youth Innovation Promotion Association CAS(No.2022366)Shenzhen Science and Technology Program(No.JCYJ20240813154813018).
文摘Horizontally aligned semiconducting single-wall carbon nanotube(s-SWCNT)arrays are ideal candidates for next-generation integrated circuits.However,the mainstream synthesis methods for obtaining s-SWCNTs mainly utilize the differences in structure and chemical reactivity between them and their metallic counterparts.These differences are too small to greatly improve their purity and reproducibility.Here we report an energy engineering strategy to expand the etching energy barrier difference of SWCNTs with different conductivities.In addition to density functional theory calculations on the energy barrier change,hydrogenation of single-wall carbon nanotubes(SWCNTs)by hydrogen plasma treatment and reversible dehydrogenation by annealing were realized experimentally.The structure-dependent hydrogenation and following selective oxidative etching of SWCNTs were demonstrated.As a result,horizontally aligned s-SWCNT arrays with high purity were obtained.
基金supported by Yunnan Major Scientific and Technological Projects(Grant No 202202AG050011)the Sichuan Science and Technology Program(No.2023YFG0218)+2 种基金Guizhou Provincial Department of Education Open Recruitment and Leadership Scientific and Technological Attack Project(Guizhou Education Technology[2024]No 003)Anshu University 2024 Annual School-Level Scientific Research Project(asxybsjj202413)Guizhou Provincial Basic Research Program(Natural Science)(No.QKHJC[2024]Youth 214).
文摘A novel Mg_(98.5)Zn_(0.5)Y alloy sheet with ultrafine grains and exceptional electromagnetic shielding performance has been fabricated using friction stir processing(FSP).This study investigates the impact of FSP on the microstructure,mechanical properties,and electromagnetic interference(EMI)shielding effectiveness(SE)of the alloy,specifically across three distinct layers within the stir zone(SZ):Top,Middle,and Bottom.The results reveal that the Mg_(12)YZn long-period stacking ordered(LPSO)phase is the predominant structure,undergoing significant grain refinement.The grain size is drastically reduced from 1.5 mm in the as-cast state to 12.6μm,10.0μm,and 7.1μm in the Top,Middle,and Bottom,respectively.This grain refinement and fragmentation of the LPSO phase into nanoscale particles result in a substantial enhancement of mechanical properties.The ultimate tensile strength(UTS)reached 358.2 MPa with an elongation(EL)of 15.1%,reflecting a 344% increase in strength and a 733% improvement in ductility compared to the as-cast material.Simultaneously,the EMI SE was maintained between 70 and 110.4 dB over a broad frequency range(30-4500 MHz).Despite the nanoscale LPSO particles contributing minimally to EMI shielding,the lamellar LPSO structure demonstrated excellent performance through multiple electromagnetic wave reflections within the matrix.These findings underscore the dual benefits of FSP in improving both mechanical strength and electromagnetic shielding effectiveness,positioning this Mg_(98.5)Zn_(0.5)Y alloy for advanced applications in the electronics and telecommunications sectors.
基金funded by the National Centre for Research and Development in Poland, project V4-JAPAN/2/15 “Development of Advanced Magnesium Alloys for Multifunctional Applications in Extreme Environments,” under statutory work at the Faculty of Material Science and Engineering Warsaw University of Technology in Polandthe International Visegrad Fund (project no. JP39421, V4Japan Joint Research Program)+3 种基金the support of the International Visegrad Fund (project V4Japan Joint Research Program, Ref. JP3936)the National Research, Development and Innovation Office (contract no. 2019-2.1.7-ERA-NET-2021-00030)Support by the Ministry of Education, Youth and Sports of the Czech Republic in the framework of Visegrad Group (V4)-Japan Joint Research Program-Advanced Materials under grant no. 8F21011 is gratefully acknowledged by K.M., D.D., and A.Fthe support from the Department of Metal and Corrosion Engineering, University of Chemical Technology, Prague, Czech Republic, while performing the tribocorrosion measurements
文摘In this study,the effect of annealing on the microstructure and following corrosion and biological properties of Mg-1.0Ca-0.5Zn-0.1Y-0.03Mn(at.%)alloy prepared by rapid solidified powder metallurgy was investigated.The annealing at 300℃ for 2 h did not change the grain size significantly;however,a slight growth of Mg_(2)Ca precipitates was observed.When the annealing temperature increased up to 400℃ for 2 h,full recrystallization of the alloy occurred;the grains and precipitates grew noticeably.Those changes were responsible for decreasing the corrosion and the tribocorrosion resistance of the alloy.Due to lowered resistance to the corrosion medium,the cell viability was also reduced.Although MG63 cells on the annealed specimens developed filopodia,cell-to-cell communication was not observed.
基金funded by the National Natural Science Foundation of China (52061020).
文摘Quantitative analysis of aluminum-silicon(Al-Si)alloy microstructure is crucial for evaluating and controlling alloy performance.Conventional analysis methods rely on manual segmentation,which is inefficient and subjective,while fully supervised deep learning approaches require extensive and expensive pixel-level annotated data.Furthermore,existing semi-supervised methods still face challenges in handling the adhesion of adjacent primary silicon particles and effectively utilizing consistency in unlabeled data.To address these issues,this paper proposes a novel semi-supervised framework for Al-Si alloy microstructure image segmentation.First,we introduce a Rotational Uncertainty Correction Strategy(RUCS).This strategy employs multi-angle rotational perturbations andMonte Carlo sampling to assess prediction consistency,generating a pixel-wise confidence weight map.By integrating this map into the loss function,the model dynamically focuses on high-confidence regions,thereby improving generalization ability while reducing manual annotation pressure.Second,we design a Boundary EnhancementModule(BEM)to strengthen boundary feature extraction through erosion difference and multi-scale dilated convolutions.This module guides the model to focus on the boundary regions of adjacent particles,effectively resolving particle adhesion and improving segmentation accuracy.Systematic experiments were conducted on the Aluminum-Silicon Alloy Microstructure Dataset(ASAD).Results indicate that the proposed method performs exceptionally well with scarce labeled data.Specifically,using only 5%labeled data,our method improves the Jaccard index and Adjusted Rand Index(ARI)by 2.84 and 1.57 percentage points,respectively,and reduces the Variation of Information(VI)by 8.65 compared to stateof-the-art semi-supervised models,approaching the performance levels of 10%labeled data.These results demonstrate that the proposed method significantly enhances the accuracy and robustness of quantitative microstructure analysis while reducing annotation costs.
基金financially supported by the Fundamental Research Funds for the Central Universities,China(No.21624408)the Guangdong Basic and Applied Basic Research Foundation,China(Nos.2023A1515012850,2024A1515010416)+2 种基金Guangzhou Science and Technology Planning Project,China(No.2024A04J9966)the National Natural Science Foundation of China(Nos.52271132,52004101)the Key Laboratory of Advanced Materials of Yunnan Province,China(No.2024KF02)。
文摘To exploit the combined strengthening effects of nanotwins and carbon nanotubes(CNTs)in Cu matrix composites,the nanotwins with a width ranging from 3 to 30 nm were incorporated into the CNTs-reinforced Cu matrix composites using cryogenic rolling and optimizing the initial particle size of the raw Cu powders.The formation of nanotwins in the Cu matrix composite reinforced by only 0.2 wt.%CNTs is accompanied by the increased dislocation density and refined Cu grain size,resulting in much better strength−ductility synergy than the referenced composite without significant nanotwins formation.The analysis of strengthening and toughening mechanisms demonstrates that the strength increment mainly derives from grain refinement strengthening,dislocation strengthening,and nanotwin strengthening.The strength increment from the contribution of the nanotwins accounts for 19.9%of the overall strength increment for the composite.Meanwhile,the retention of good tensile ductility can be reasonably explained by the increased dislocation accommodation ability due to the formed nanotwins and the decreased induced dislocation proliferation.
基金supported by the Foundation of Yunnan Province(Nos.202301AU070021,202201BE070001-027)the Test Foundation of KUST(No.2022T20210208).
文摘Halide perovskite materials have received considerable attention for solar cells,LEDs,lasers etc.owing to their controllable physicochemical properties and structural advantages.However,little research has focused on energy storage and conversion applications,such as use as anodes in lithium-ion batteries.In this paper,all-inorganic lead-free halide perovskite Cs_(3)Bi_(2)Cl_(9)powders were synthesized by the grinding method,and the lattice was successfully adjusted via introducing Mn^(2+).The characterization results show that Mn-ion substitution can cause local lattice distortion to restructure the lattice,which will cause a mixed arrangement of[BiCl_(6)]octahedra to improve the performance of the anode material.This new material can provide a feasible solution for solving the problem of low specific capacity anode materials caused by unstable crystal structures,and also indicates that such perovskites with unique crystal structures and lattice tunability have broad application prospects in lithium-ion batteries.
