The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ...The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.展开更多
The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,fle...The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.展开更多
Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pell...Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.展开更多
The microstructure of high Nb-TiAl alloys was optimized by the addition of a small amount of Ta elements to further improve their properties.A series of Ti46Al1.5Cr8Nb-xTa(x=0.2,0.4,0.6,0.8,1.0,at.%)alloys were prepar...The microstructure of high Nb-TiAl alloys was optimized by the addition of a small amount of Ta elements to further improve their properties.A series of Ti46Al1.5Cr8Nb-xTa(x=0.2,0.4,0.6,0.8,1.0,at.%)alloys were prepared by vacuum arc melting.The microstructure,mechanical properties,and related influencing mechanisms were systematically investigated.The results indicate that the solidification microstructure of the Ti46Al1.5Cr8Nb-xTa alloys comprises theγ-TiAl phase,α_(2)-Ti_(3)Al phase,and B2 phase.As the Ta content increases from 0.2 at.%to 1.0 at.%,the content ofα_(2)phase and B2 phase increases,while theγphase content decreases.Among them,the B2 phase shows the most pronounced change,being significantly refined,with its content increasing from 12.49%to 21.91%.In addition,the average size of the lamellar colony decreases from 160.65 to 94.44μm.The addition of the Ta element shifts the solidification path toward lower aluminum concentrations,leading to changes in phase content.The tantalum-induced increase in the B2 phase and enhanced supercooling at the solidification front provide the basis for lamellar colony refinement.Compressive testing at room temperature reveals that the Ti46 Al1.5 Cr8 Nb0.4 Ta alloy exhibits optimal compressive properties,achieving a compressive strength of 2,434 MPa and a compressive strain of 33.1%.The improvement of its properties is attributed to a combination of lamellar colony refinement,solid solution strengthening resulting from the incorporation of Ta element,and a reduction in the c/a of theγphase.展开更多
(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperatu...(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperature properties.This study systematically investigates the mechanical properties of(NbZrHfTi)C high-entropy ceramics by employing first-principles density functional theory,combined with the Debye-Grüneisen model,to explore the variations in their thermophysical properties with temperature(0–2000 K)and pressure(0–30 GPa).Thermodynamically,the calculated mixing enthalpy and Gibbs free energy confirm the feasibility of forming a stable single-phase solid solution in(NbZrHfTi)C.The calculated results of the elastic stiffness constant indicate that the material meets the mechanical stability criteria of the cubic crystal system,further confirming the structural stability.Through evaluation of key mechanical parameters—bulk modulus,shear modulus,Young’s modulus,and Poisson’s ratio—we provide comprehensive insight into the macro-mechanical behaviour of the material and its correlation with the underlying microstructure.Notably,compared to traditional binary carbides and their average properties,(NbZrHfTi)C exhibits higher Vickers hardness(Approximately 28.5 GPa)and fracture toughness(Approximately 3.4 MPa⋅m^(1/2)),which can be primarily attributed to the lattice distortion and solid-solution strengthening mechanism.The study also utilizes the quasi-harmonic approximation method to predict the material’s thermophysical properties,including Debye temperature(initial value around 563 K),thermal expansion coefficient(approximately 8.9×10^(−6) K−1 at 2000 K),and other key parameters such as heat capacity at constant volume.The results show that within the studied pressure and temperature ranges,(NbZrHfTi)C consistently maintains a stable phase structure and good thermomechanical properties.The thermal expansion coefficient increasing with temperature,while heat capacity approaches the Dulong-Petit limit at elevated temperatures.These findings underscore the potential of(NbZrHfTi)C applications in ultra-high temperature thermal protection systems,cutting tool coatings,and nuclear structural materials.展开更多
The composition−property relationship of 18 quaternary high entropy diborides(HEBs)consisting of boron and IVB,VB and VIB transition metals(TM)was investigated using first-principles calculations.A valence electron co...The composition−property relationship of 18 quaternary high entropy diborides(HEBs)consisting of boron and IVB,VB and VIB transition metals(TM)was investigated using first-principles calculations.A valence electron concentration−relative electronegativity(VEC−REN)composite descriptor was developed to effectively predict the mechanical properties of HEBs.The results demonstrate that with a fixed VEC,the rise of the REN makes HEBs harder but more brittle when the electronegativity of doped TM atoms is lower than that of boron atoms.However,HEBs become softer and more ductile as REN increases if the doped TM atoms have higher electronegativity than boron atoms.The VEC−REN composite descriptor can accurately classify and predict the mechanical properties of HEBs with different components,which provides important theoretical guidance for the rapid design and development of novel high-entropy ceramic materials.展开更多
Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of re...Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.展开更多
A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The resu...A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.展开更多
High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as not...High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.展开更多
The microstructures and mechanical properties of Al-8.3Zn-3.3Cu-2.2Mg alloys prepared via hot extrusion and liquid forging methods were investigated.Results show that based on DEFORM simulation analysis,the optimal ho...The microstructures and mechanical properties of Al-8.3Zn-3.3Cu-2.2Mg alloys prepared via hot extrusion and liquid forging methods were investigated.Results show that based on DEFORM simulation analysis,the optimal hot extrusion parameters are determined as ingot initial temperature of 380°C and extrusion speed of 3 mm/s.The hot-extruded aluminum alloy after T6 heat treatment presents superior mechanical properties with yield strength of 519.6 MPa,ultimate tensile strength of 582.1 MPa,and elongation of 11.0%.Compared with the properties of gravity-cast and liquid-forged alloys,the yield strength of hot-extruded alloy increases by 30.8%and 4.9%,and the ultimate tensile strength improves by 43.5%and 10.2%,respectively.The significant improvement in tensile strength of the hot-extruded alloys is attributed to the elimination of casting defects and the refinement of matrix grain and eutectic phases.In addition,the hot-extruded alloy demonstrates superior plasticity compared with the liquid-forged alloy.This is because severe plastic deformation occurs during hot extrusion,which effectively breaks and disperses the eutectic phases,facilitating the dissolution and precipitation of the second phases and inhibiting the microcrack initiation.展开更多
Ag-Cu-In-Ti low-temperature filler was used to braze the diamond and copper,and the effects of brazing temperature and soaking time on the microstructure and mechanical properties of the joints were investigated.In ad...Ag-Cu-In-Ti low-temperature filler was used to braze the diamond and copper,and the effects of brazing temperature and soaking time on the microstructure and mechanical properties of the joints were investigated.In addition,the joint formation mechanism was discussed,and the correlation between joint microstructure and mechanical performance was established.Results show that adding appropriate amount of In into the filler can significantly reduce the filler melting point and enhance the wettability of filler on diamond.When the brazing temperature is 750°C and the soaking time is 10 min,a uniformly dense braze seam with excellent metallurgical bonding can be obtained,and its average joint shear strength reaches 322 MPa.The lower brazing temperature can mitigate the risk of diamond graphitization and also reduce the residual stresses during joining.展开更多
Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusi...Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.展开更多
Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably pro...Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably promotes the refinement of the alloy's grains.Ce and La elements are combined with Si and other elements to form rare earth phases,improving the morphology and distribution of precipitates and mitigating the adverse effects ofβ-Fe phases on the microstructure and mechanical properties of alloy.However,excessive rare earth content poses challenges;it not only leads to a decrease in Mg-Si strengthening phase by binding with Si but also promotes the formation of larger or numerous rare earth phases that may act as initiation points for cracks,thereby impeding the improvement of the structure and performance of alloy.The composite addition of cerium-rich rare earths and Al-Ti-B not only preserves the strength of the alloy but also significantly enhances the plasticity of the 6061 as-cast alloy.At a composite addition ratio of Al-Ti-B:RE=2:1,the newly developed 6061-RE aluminum alloy exhibits increased average elongation by 50%and 45%in its as-cast and homogenized states,respectively,compared to the baseline 6061 alloy,facilitating subsequent deformation processing.After solution treatment at 540℃for 1 h and aging at 180℃for 5 h,the average ultimate tensile strength and yield strength of 6061-RE alloys reach 313.2 and 283.1 MPa,increased by 12.3%and 14.5%compared with those of the original alloy,respectively,and the average elongation is improved by 41%.展开更多
To enhance the mechanical properties of Mo alloys prepared through laser powder bed fusion(LPBF),a hot isostatic pressing(HIP)treatment was used.Results show that following HIP treatment,the porosity decreases from 0....To enhance the mechanical properties of Mo alloys prepared through laser powder bed fusion(LPBF),a hot isostatic pressing(HIP)treatment was used.Results show that following HIP treatment,the porosity decreases from 0.27%to 0.22%,enabling the elements Mo and Ti to diffuse fully and to distribute more uniformly,and to forming a substantial number of low-angle grain boundaries.The tensile strength soars from 286±32 MPa to 598±22 MPa,while the elongation increases from 0.08%±0.02%to 0.18%±0.02%,without notable alterations in grain morphology during the tensile deformation.HIP treatment eliminates the molten pool boundaries,which are the primary source for premature failure in LPBFed Mo alloys.Consequently,HIP treatment emerges as a novel and effective approach for strengthening the mechanical properties of LPBFed Mo alloys,offering a fresh perspective on producing high-performance Mo-based alloys.展开更多
Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uni...Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uniform deformation that occurs at room temperature.Once cracks nucleate,they will rapidly propagate into vertical splitting cracks.Here,we introduce multiple phases including FCC and HCP phases into the NbMoTa RMEA via appropriate addition of carbon.The results show that multiple-phase synergy effectively suppresses non-uniform deformation,thereby delaying the onset of vertical splitting cracks.An optimal combination of compressive strength-plasticity is achieved by the(NbMoTa)_(92.5)C_(7.5) alloy.The significant improvement in room-temperature mechanical properties can be attributed to its hierarchical microstructure:in the mesoscale,the BCC matrix is divided by eutectic structures;while at the microscale,the BCC matrix is further refined by abundant lath-like FCC precipitates.The FCC precip-itates contain high-density stacking faults,acting as a dislocation source under compressive loading.The HCP phase in the eutectic microstructures,in turn,acts as a strong barrier to dislocation movement and simultaneously increases the dislocation storage capacity.These findings open a new route to tailor the microstructure and mechanical properties of RH/MEAs.展开更多
The morphology and dimension of W phases play an important role in determining mechanical properties of Mg-RE-Zn(where RE denotes rare earth elements)alloys.In this study,theγ′platelet and W particle occurred in the...The morphology and dimension of W phases play an important role in determining mechanical properties of Mg-RE-Zn(where RE denotes rare earth elements)alloys.In this study,theγ′platelet and W particle occurred in the aged Mg-2Dy-0.5Zn(at.%)alloys were investigated by aberration-corrected scanning transmission electron microscopy.A novel formation mechanism of W phase was proposed,and its effects on the morphology and dimension of W particle,as well as mechanical properties of Mg-2Dy-0.5Zn alloys,were also discussed particularly.Different from other Mg-RE-Zn alloys,the nucleation and growth of W particle in Mg-Dy-Zn alloys mainly depend on the precipitatedγ′platelet.Primarily,a mass of Dy and Zn solute atoms concentrated nearγ′platelet or between two adjacentγ′platelets can meet the composition requirement of W particle nucleation.Next,the smaller interfacial mismatch between W andγ′facilitates the nucleation and growth of W particle.Thirdly,the growth of W particle can be achieved by consuming the surroundingγ′platelets.The nucleation and growth mechanisms make W particles exhibit rectangular or leaf-like and remain at the nanoscale.The coexistence ofγ′platelets and nanoscale W particles,and some better interfacial relationships between phases,lead to a high strength-ductility synergy of alloy.The findings may provide some fundamental guidelines for the microstructure design and optimization of new-type Mg-based alloys.展开更多
Irregular bone scaffolds fabricated using the Voronoi tessellation method resemble the morphology and properties of human cancellous bones.This has become a prominent topic in bone tissue engineering research in recen...Irregular bone scaffolds fabricated using the Voronoi tessellation method resemble the morphology and properties of human cancellous bones.This has become a prominent topic in bone tissue engineering research in recent years.However,studies on the radial-gradient design of irregular bionic scaffolds are limited.Therefore,this study aims to develop a radial-gradient structure similar to that of natural long bones,enhancing the development of bionic bone scaffolds.A novel gradient method was adopted to maintain constant porosity,control the seed site-specific distribution within the irregular porous structure,and vary the strut diameter to generate radial gradients.The irregular scaffolds were compared with four conventional scaffolds(cube,pillar BCC,vintiles,and diamond)in terms of permeability,stress concentration characteristics,and mechanical properties.The results indicate that the radial-gradient irregular porous structure boasts the widest permeability range and superior stress distribution compared to conventional scaffolds.With an elastic modulus ranging from 4.20 GPa to 22.96 GPa and a yield strength between 68.37 MPa and 149.40 MPa,it meets bone implant performance requirements and demonstrates significant application potential.展开更多
In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural prope...In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural properties of schist subjected to four conditions were investigated:freeze-thaw cycles in air(FTA),freeze-thaw cycles in water(FTW),dry-wet cycles(DW),and dry-wet-freeze-thaw cycles(DWFT).Uniaxial compressive strength(UCS),water absorption,ultrasonication,low-field nuclear magnetic resonance,and scanning electron microscopy analyses were conducted.The integrity attenuation characteristics of the longitudinal wave velocity,UCS,and elastic modulus were analyzed.The results showed that liquid water emerged as a critical factor in reducing the brittleness of schist.The attenuation function model accurately described the peak stress and static elastic modulus of schist in various media(R2>0.97).Different media affected the schist deterioration and half-life,with the FTW-immersed samples having a half-life of 28 cycles.Furthermore,the longitudinal wave velocity decreased as the number of cycles increased,with the FTW showing the most significant reduction and having the shortest half-life of 208 cycles.Moreover,the damage variables of compressive strength and elastic modulus increased with the number of cycles.After 40 cycles,the schist exposed to FTW exhibited the highest damage variables and saturated water content.展开更多
基金supported by the National Natural Science Foundation of China (Grant Nos.T2325004 and 52161160330)the National Natural Science Foundation of China (Grants No.12504233)+2 种基金Advanced MaterialsNational Science and Technology Major Project (Grant No.2024ZD0606900)the Talent Hub for “AI+New Materials” Basic Researchthe Key Research and Development Program of Ningbo (Grant No.2025Z088)。
文摘The functional properties of glasses are governed by their formation history and the complex relaxation processes they undergo.However,under extreme conditions,glass behaviors are still elusive.In this study,we employ simulations with varied protocols to evaluate the effectiveness of different descriptors in predicting mechanical properties across both low-and high-pressure regimes.Our findings demonstrate that conventional structural and configurational descriptors fail to correlate with the mechanical response following pressure release,whereas the activation energy descriptor exhibits robust linearity with shear modulus after correcting for pressure effects.Notably,the soft mode parameter emerges as an ideal and computationally efficient alternative for capturing this mechanical behavior.These findings provide critical insights into the influence of pressure on glassy properties,integrating the distinct features of compressed glasses into a unified theoretical framework.
基金supported by the NSFC(12474071)Natural Science Foundation of Shandong Province(ZR2024YQ051)+5 种基金Open Research Fund of State Key Laboratory of Materials for Integrated Circuits(SKLJC-K2024-12)the Shanghai Sailing Program(23YF1402200,23YF1402400)Natural Science Foundation of Jiangsu Province(BK20240424)Taishan Scholar Foundation of Shandong Province(tsqn202408006)Young Talent of Lifting engineering for Science and Technology in Shandong,China(SDAST2024QTB002)the Qilu Young Scholar Program of Shandong University.
文摘The advancement of flexible memristors has significantly promoted the development of wearable electronic for emerging neuromorphic computing applications.Inspired by in-memory computing architecture of human brain,flexible memristors exhibit great application potential in emulating artificial synapses for highefficiency and low power consumption neuromorphic computing.This paper provides comprehensive overview of flexible memristors from perspectives of development history,material system,device structure,mechanical deformation method,device performance analysis,stress simulation during deformation,and neuromorphic computing applications.The recent advances in flexible electronics are summarized,including single device,device array and integration.The challenges and future perspectives of flexible memristor for neuromorphic computing are discussed deeply,paving the way for constructing wearable smart electronics and applications in large-scale neuromorphic computing and high-order intelligent robotics.
基金financial support by the National Key Research and Development Program of China(No.2023YFC2907801)the Hunan Provincial Natural Science Foundation of China(No.2023JJ40760)the Scientific and Technological Project of Yunnan Precious Metals Laboratory,China(No.YPML-2023050276)。
文摘Bentonite is a necessary binder in producing pellets.Its excessive use reduces the iron grade of pellets and increases production costs.Minimizing bentonite dosage is essential for producing high-quality iron ore pellets.Addressing the gap in the application of organically-intercalated modified bentonite in the pelletizing field,this study introduces an innovative modification process for bentonite that employs the synergistic effect of mechanical force and dimethyl sulfoxide to enhance the intercalation of organic compounds within bentonite,thus significantly enhancing its binding performance.The colloid value and swell capacity of modified bentonite(98.5 m L/3g and 55.0 m L/g)were much higher than the original bentonite(90.5 m L/3g and 17.5 m L/g).With the decrease of bentonite dosage from1.5wt%to 1.0wt%,the drop number of green pellets from a height of 0.5 m and the compressive strengths of roasted pellets using the modified bentonite(6.0 times and 2916 N per pellet)were significantly higher than those of the original bentonite(4.0 times and 2739 N per pellet).This study provides a comprehensive analysis of the intercalation modification mechanism of bentonite,offering crucial technical insights for the development of high-performance modified bentonite as iron ore pellet binders.
基金the financial support by the Major Science and Technology Achievement Transformation Project in Heilongjiang Province(No.ZC2023SH0075)the National Natural Science Foundation of China(Nos.52425401,U2441255,52474377,and 52371015)+1 种基金the Young Elite Scientists Sponsorship·Program by CAST(No.2021QNRC001)the Henan Provincial Key Research and Development&Promotion Special Program(No.251111231400)。
文摘The microstructure of high Nb-TiAl alloys was optimized by the addition of a small amount of Ta elements to further improve their properties.A series of Ti46Al1.5Cr8Nb-xTa(x=0.2,0.4,0.6,0.8,1.0,at.%)alloys were prepared by vacuum arc melting.The microstructure,mechanical properties,and related influencing mechanisms were systematically investigated.The results indicate that the solidification microstructure of the Ti46Al1.5Cr8Nb-xTa alloys comprises theγ-TiAl phase,α_(2)-Ti_(3)Al phase,and B2 phase.As the Ta content increases from 0.2 at.%to 1.0 at.%,the content ofα_(2)phase and B2 phase increases,while theγphase content decreases.Among them,the B2 phase shows the most pronounced change,being significantly refined,with its content increasing from 12.49%to 21.91%.In addition,the average size of the lamellar colony decreases from 160.65 to 94.44μm.The addition of the Ta element shifts the solidification path toward lower aluminum concentrations,leading to changes in phase content.The tantalum-induced increase in the B2 phase and enhanced supercooling at the solidification front provide the basis for lamellar colony refinement.Compressive testing at room temperature reveals that the Ti46 Al1.5 Cr8 Nb0.4 Ta alloy exhibits optimal compressive properties,achieving a compressive strength of 2,434 MPa and a compressive strain of 33.1%.The improvement of its properties is attributed to a combination of lamellar colony refinement,solid solution strengthening resulting from the incorporation of Ta element,and a reduction in the c/a of theγphase.
基金supported by the National Natural Science Foundation of China(Nos.92166105 and 52005053)High-Tech Industry Science and Technology Innovation Leading Program of Hunan Province(No.2020GK2085)the Science and Technology Innovation Program of Hunan Province(No.2021RC3096).
文摘(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperature properties.This study systematically investigates the mechanical properties of(NbZrHfTi)C high-entropy ceramics by employing first-principles density functional theory,combined with the Debye-Grüneisen model,to explore the variations in their thermophysical properties with temperature(0–2000 K)and pressure(0–30 GPa).Thermodynamically,the calculated mixing enthalpy and Gibbs free energy confirm the feasibility of forming a stable single-phase solid solution in(NbZrHfTi)C.The calculated results of the elastic stiffness constant indicate that the material meets the mechanical stability criteria of the cubic crystal system,further confirming the structural stability.Through evaluation of key mechanical parameters—bulk modulus,shear modulus,Young’s modulus,and Poisson’s ratio—we provide comprehensive insight into the macro-mechanical behaviour of the material and its correlation with the underlying microstructure.Notably,compared to traditional binary carbides and their average properties,(NbZrHfTi)C exhibits higher Vickers hardness(Approximately 28.5 GPa)and fracture toughness(Approximately 3.4 MPa⋅m^(1/2)),which can be primarily attributed to the lattice distortion and solid-solution strengthening mechanism.The study also utilizes the quasi-harmonic approximation method to predict the material’s thermophysical properties,including Debye temperature(initial value around 563 K),thermal expansion coefficient(approximately 8.9×10^(−6) K−1 at 2000 K),and other key parameters such as heat capacity at constant volume.The results show that within the studied pressure and temperature ranges,(NbZrHfTi)C consistently maintains a stable phase structure and good thermomechanical properties.The thermal expansion coefficient increasing with temperature,while heat capacity approaches the Dulong-Petit limit at elevated temperatures.These findings underscore the potential of(NbZrHfTi)C applications in ultra-high temperature thermal protection systems,cutting tool coatings,and nuclear structural materials.
基金the National Natural Science Foundation of China (Nos. 52071179, 52271033)the Key Program of National Natural Science Foundation of China (No. 51931003)+2 种基金the Natural Science Foundation of Jiangsu Province, China (No. BK20221493)the Jiangsu Province Leading Edge Technology Basic Research Major Project, China (No. BK20222014)the Foundation of “Qinglan Project” for Colleges and Universities in Jiangsu Province, China。
文摘The composition−property relationship of 18 quaternary high entropy diborides(HEBs)consisting of boron and IVB,VB and VIB transition metals(TM)was investigated using first-principles calculations.A valence electron concentration−relative electronegativity(VEC−REN)composite descriptor was developed to effectively predict the mechanical properties of HEBs.The results demonstrate that with a fixed VEC,the rise of the REN makes HEBs harder but more brittle when the electronegativity of doped TM atoms is lower than that of boron atoms.However,HEBs become softer and more ductile as REN increases if the doped TM atoms have higher electronegativity than boron atoms.The VEC−REN composite descriptor can accurately classify and predict the mechanical properties of HEBs with different components,which provides important theoretical guidance for the rapid design and development of novel high-entropy ceramic materials.
基金Funded by Natural Science Foundation of Guangxi(No.2025GXNSFBA069565)Guangxi Science and Technology Program(No.AD25069101)Guangxi Bagui Scholars Fund。
文摘Crushing waste coral concrete into recycled aggregates to create recycled coral aggregate concrete(RCAC)contributes to sustainable construction development on offshore islands and reefs.To investigate the impact of recycled coral aggregate on concrete properties,this study performed a comprehensive analysis of the physical properties of recycled coral aggregate and the basic mechanical properties and microstructure of RCAC.The test results indicate that,compared to coral debris,the crushing index of recycled coral aggregate was reduced by 9.4%,while porosity decreased by 33.5%.Furthermore,RCAC retained the early strength characteristics of coral concrete,with compressive strength and flexural strength exhibiting a notable increase as the water-cement ratio decreased.Under identical conditions,the compressive strength and flexural strength of RCAC were 12.7% and 2.5% higher than coral concrete's,respectively,with porosity correspondingly reduced from 3.13% to 5.11%.This enhancement could be attributed to the new mortar filling the recycled coral aggregate.Scanning electron microscopy(SEM)analysis revealed three distinct interface transition zones within RCAC,with the‘new mortar-old mortar’interface identified as the weakest.The above findings provided a reference for the sustainable use of coral concrete in constructing offshore islands.
基金supported by Guangdong Major Project of Basic and Applied Basic Research, China (No. 2020B0301030006)Fundamental Research Funds for the Central Universities, China (No. SWU-XDJH202313)+1 种基金Chongqing Postdoctoral Science Foundation Funded Project, China (No. 2112012728014435)the Chongqing Postgraduate Research and Innovation Project, China (No. CYS23197)。
文摘A new method was proposed for preparing AZ31/1060 composite plates with a corrugated interface,which involved cold-pressing a corrugated surface on the Al plate and then hot-pressing the assembled Mg/Al plate.The results show that cold-pressing produces intense plastic deformation near the corrugated surface of the Al plate,which promotes dynamic recrystallization of the Al substrate near the interface during the subsequent hot-pressing.In addition,the initial corrugation on the surface of the Al plate also changes the local stress state near the interface during hot pressing,which has a large effect on the texture components of the substrates near the corrugated interface.The construction of the corrugated interface can greatly enhance the shear strength by 2−4 times due to the increased contact area and the strong“mechanical gearing”effect.Moreover,the mechanical properties are largely depended on the orientation relationship between corrugated direction and loading direction.
基金supported by National Natural Science Foundation of China(Grant No.52171032)Hebei Natural Science Foundation(Grant No.E2023501002)Fundamental Research Funds for the Central Universities(Grant No.2024GFYD003)。
文摘High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.
基金Natural Science Foundation of Shandong Province of China(ZR2023QE193)。
文摘The microstructures and mechanical properties of Al-8.3Zn-3.3Cu-2.2Mg alloys prepared via hot extrusion and liquid forging methods were investigated.Results show that based on DEFORM simulation analysis,the optimal hot extrusion parameters are determined as ingot initial temperature of 380°C and extrusion speed of 3 mm/s.The hot-extruded aluminum alloy after T6 heat treatment presents superior mechanical properties with yield strength of 519.6 MPa,ultimate tensile strength of 582.1 MPa,and elongation of 11.0%.Compared with the properties of gravity-cast and liquid-forged alloys,the yield strength of hot-extruded alloy increases by 30.8%and 4.9%,and the ultimate tensile strength improves by 43.5%and 10.2%,respectively.The significant improvement in tensile strength of the hot-extruded alloys is attributed to the elimination of casting defects and the refinement of matrix grain and eutectic phases.In addition,the hot-extruded alloy demonstrates superior plasticity compared with the liquid-forged alloy.This is because severe plastic deformation occurs during hot extrusion,which effectively breaks and disperses the eutectic phases,facilitating the dissolution and precipitation of the second phases and inhibiting the microcrack initiation.
基金National MCF Energy R&D Program(2019YFE03100400)。
文摘Ag-Cu-In-Ti low-temperature filler was used to braze the diamond and copper,and the effects of brazing temperature and soaking time on the microstructure and mechanical properties of the joints were investigated.In addition,the joint formation mechanism was discussed,and the correlation between joint microstructure and mechanical performance was established.Results show that adding appropriate amount of In into the filler can significantly reduce the filler melting point and enhance the wettability of filler on diamond.When the brazing temperature is 750°C and the soaking time is 10 min,a uniformly dense braze seam with excellent metallurgical bonding can be obtained,and its average joint shear strength reaches 322 MPa.The lower brazing temperature can mitigate the risk of diamond graphitization and also reduce the residual stresses during joining.
基金supported by the National Science and Technology Major Project,China(No.2019-VI-0004-0118)the National Natural Science Foundation of China(No.51771152)the National Key R&D Program of China(No.2018YFB1106800)。
文摘Microstructure,texture,and mechanical properties of the extruded Mg-2.49Nd-1.82Gd-0.2Zn-0.2Zr alloy were investigated at different extrusion temperatures(260 and 320℃),extrusion ratios(10:1,15:1,and 30:1),and extrusion speeds(3 and 6 mm/s).The experimental results exhibited that the grain sizes after extrusion were much finer than that of the homogenized alloy,and the second phase showed streamline distribution along the extrusion direction(ED).With extrusion temperature increased from 260 to 320℃,the microstructure,texture,and mechanical properties of alloys changed slightly.The dynamic recrystallization(DRX)degree and grain sizes enhanced as the extrusion ratio increased from 10:1 to 30:1,and the strength gradually decreased but elongation(EL)increased.With the extrusion speed increased from 3 to 6 mm/s,the grain sizes and DRX degree increased significantly,and the samples presented the typical<2111>-<1123>rare-earth(RE)textures.The alloy extruded at 260℃ with extrusion ratio of 10:1 and extrusion speed of 3 mm/s showed the tensile yield strength(TYS)of 213 MPa and EL of 30.6%.After quantitatively analyzing the contribution of strengthening mechanisms,it was found that the grain boundary strengthening and dislocation strengthening played major roles among strengthening contributions.These results provide some guidelines for enlarging the industrial application of extruded Mg-RE alloy.
基金Subproject of Inner Mongolia Autonomous Region Key Research and Development and Achievement Transformation Plan Project(2023YFDZ0064,2023KJHZ0020,2022YFDZ0097)Natural Science Foundation of Inner Mongolia Autonomous Region of China(2022QN05040)+1 种基金Basic Research Funds for Directly Affiliated Universities in Inner Mongolia Autonomous Region(JY20220093)Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(NJYT24008)。
文摘Modification of 6061 aluminum alloy was conducted through composite addition of cerium-rich rare earths and Al-Ti-B.Results show that the composite addition of Al-Ti-B and Ce/La element at a specific ratio notably promotes the refinement of the alloy's grains.Ce and La elements are combined with Si and other elements to form rare earth phases,improving the morphology and distribution of precipitates and mitigating the adverse effects ofβ-Fe phases on the microstructure and mechanical properties of alloy.However,excessive rare earth content poses challenges;it not only leads to a decrease in Mg-Si strengthening phase by binding with Si but also promotes the formation of larger or numerous rare earth phases that may act as initiation points for cracks,thereby impeding the improvement of the structure and performance of alloy.The composite addition of cerium-rich rare earths and Al-Ti-B not only preserves the strength of the alloy but also significantly enhances the plasticity of the 6061 as-cast alloy.At a composite addition ratio of Al-Ti-B:RE=2:1,the newly developed 6061-RE aluminum alloy exhibits increased average elongation by 50%and 45%in its as-cast and homogenized states,respectively,compared to the baseline 6061 alloy,facilitating subsequent deformation processing.After solution treatment at 540℃for 1 h and aging at 180℃for 5 h,the average ultimate tensile strength and yield strength of 6061-RE alloys reach 313.2 and 283.1 MPa,increased by 12.3%and 14.5%compared with those of the original alloy,respectively,and the average elongation is improved by 41%.
基金National Natural Science Foundation of China(52105385)Stable Support Plan Program of Shenzhen Natural Science Fund(20220810132537001)+2 种基金Guangdong Basic and Applied Basic Research Foundation(2022A1515010781)Joint Fund of Henan Province Science and Technology R&D Program(225200810002)Fundamental Research Funds of Henan Academy of Sciences(240621041)。
文摘To enhance the mechanical properties of Mo alloys prepared through laser powder bed fusion(LPBF),a hot isostatic pressing(HIP)treatment was used.Results show that following HIP treatment,the porosity decreases from 0.27%to 0.22%,enabling the elements Mo and Ti to diffuse fully and to distribute more uniformly,and to forming a substantial number of low-angle grain boundaries.The tensile strength soars from 286±32 MPa to 598±22 MPa,while the elongation increases from 0.08%±0.02%to 0.18%±0.02%,without notable alterations in grain morphology during the tensile deformation.HIP treatment eliminates the molten pool boundaries,which are the primary source for premature failure in LPBFed Mo alloys.Consequently,HIP treatment emerges as a novel and effective approach for strengthening the mechanical properties of LPBFed Mo alloys,offering a fresh perspective on producing high-performance Mo-based alloys.
基金financial support from the Na-tional Natural Science Foundation of China(No.52231006)National Key Research and Development Program of China(No.2017YFB0702003)the National Natural Science Foundation of China(No.51871217).
文摘Refractory high/medium-entropy alloys(RH/MEAs)are known for their outstanding performance at el-evated temperatures;however,they usually exhibit poor room-temperature plasticity,which can be at-tributed to the non-uniform deformation that occurs at room temperature.Once cracks nucleate,they will rapidly propagate into vertical splitting cracks.Here,we introduce multiple phases including FCC and HCP phases into the NbMoTa RMEA via appropriate addition of carbon.The results show that multiple-phase synergy effectively suppresses non-uniform deformation,thereby delaying the onset of vertical splitting cracks.An optimal combination of compressive strength-plasticity is achieved by the(NbMoTa)_(92.5)C_(7.5) alloy.The significant improvement in room-temperature mechanical properties can be attributed to its hierarchical microstructure:in the mesoscale,the BCC matrix is divided by eutectic structures;while at the microscale,the BCC matrix is further refined by abundant lath-like FCC precipitates.The FCC precip-itates contain high-density stacking faults,acting as a dislocation source under compressive loading.The HCP phase in the eutectic microstructures,in turn,acts as a strong barrier to dislocation movement and simultaneously increases the dislocation storage capacity.These findings open a new route to tailor the microstructure and mechanical properties of RH/MEAs.
基金supported by Natural Science Foundation of Liaoning Province of China under Grant No.2020-MS-085。
文摘The morphology and dimension of W phases play an important role in determining mechanical properties of Mg-RE-Zn(where RE denotes rare earth elements)alloys.In this study,theγ′platelet and W particle occurred in the aged Mg-2Dy-0.5Zn(at.%)alloys were investigated by aberration-corrected scanning transmission electron microscopy.A novel formation mechanism of W phase was proposed,and its effects on the morphology and dimension of W particle,as well as mechanical properties of Mg-2Dy-0.5Zn alloys,were also discussed particularly.Different from other Mg-RE-Zn alloys,the nucleation and growth of W particle in Mg-Dy-Zn alloys mainly depend on the precipitatedγ′platelet.Primarily,a mass of Dy and Zn solute atoms concentrated nearγ′platelet or between two adjacentγ′platelets can meet the composition requirement of W particle nucleation.Next,the smaller interfacial mismatch between W andγ′facilitates the nucleation and growth of W particle.Thirdly,the growth of W particle can be achieved by consuming the surroundingγ′platelets.The nucleation and growth mechanisms make W particles exhibit rectangular or leaf-like and remain at the nanoscale.The coexistence ofγ′platelets and nanoscale W particles,and some better interfacial relationships between phases,lead to a high strength-ductility synergy of alloy.The findings may provide some fundamental guidelines for the microstructure design and optimization of new-type Mg-based alloys.
基金the National Natural Science Foundation of China(No.52165026)。
文摘Irregular bone scaffolds fabricated using the Voronoi tessellation method resemble the morphology and properties of human cancellous bones.This has become a prominent topic in bone tissue engineering research in recent years.However,studies on the radial-gradient design of irregular bionic scaffolds are limited.Therefore,this study aims to develop a radial-gradient structure similar to that of natural long bones,enhancing the development of bionic bone scaffolds.A novel gradient method was adopted to maintain constant porosity,control the seed site-specific distribution within the irregular porous structure,and vary the strut diameter to generate radial gradients.The irregular scaffolds were compared with four conventional scaffolds(cube,pillar BCC,vintiles,and diamond)in terms of permeability,stress concentration characteristics,and mechanical properties.The results indicate that the radial-gradient irregular porous structure boasts the widest permeability range and superior stress distribution compared to conventional scaffolds.With an elastic modulus ranging from 4.20 GPa to 22.96 GPa and a yield strength between 68.37 MPa and 149.40 MPa,it meets bone implant performance requirements and demonstrates significant application potential.
基金supported by the National Natural Science Foundation of China(Nos.42171108 and 42101136)Sichuan Science and Technology Program(Nos.2024NSFSC2007 and2025YFHZ0273)Natural Science Starting Project of SWPU(No.2024QHZ029)。
文摘In cold regions,slope rocks are inevitably impacted by freeze-thaw,dry-wet cycles and their alternating actions,leading to strength weakening and pore degradation.In this study,the mechanical and microstructural properties of schist subjected to four conditions were investigated:freeze-thaw cycles in air(FTA),freeze-thaw cycles in water(FTW),dry-wet cycles(DW),and dry-wet-freeze-thaw cycles(DWFT).Uniaxial compressive strength(UCS),water absorption,ultrasonication,low-field nuclear magnetic resonance,and scanning electron microscopy analyses were conducted.The integrity attenuation characteristics of the longitudinal wave velocity,UCS,and elastic modulus were analyzed.The results showed that liquid water emerged as a critical factor in reducing the brittleness of schist.The attenuation function model accurately described the peak stress and static elastic modulus of schist in various media(R2>0.97).Different media affected the schist deterioration and half-life,with the FTW-immersed samples having a half-life of 28 cycles.Furthermore,the longitudinal wave velocity decreased as the number of cycles increased,with the FTW showing the most significant reduction and having the shortest half-life of 208 cycles.Moreover,the damage variables of compressive strength and elastic modulus increased with the number of cycles.After 40 cycles,the schist exposed to FTW exhibited the highest damage variables and saturated water content.
