The remarkable properties of carbon nanotubes(CNTs)have led to promising applications in the field of electromagnetic inter-ference(EMI)shielding.However,for macroscopic CNT assemblies,such as CNT film,achieving high ...The remarkable properties of carbon nanotubes(CNTs)have led to promising applications in the field of electromagnetic inter-ference(EMI)shielding.However,for macroscopic CNT assemblies,such as CNT film,achieving high electrical and mechanical properties remains challenging,which heavily depends on the tube-tube interac-tions of CNTs.Herein,we develop a novel strategy based on metal-organic decomposition(MOD)to fabricate a flexible silver-carbon nanotube(Ag-CNT)film.The Ag particles are introduced in situ into the CNT film through annealing of MOD,leading to enhanced tube-tube interactions.As a result,the electrical conductivity of Ag-CNT film is up to 6.82×10^(5) S m^(-1),and the EMI shielding effectiveness of Ag-CNT film with a thickness of~7.8μm exceeds 66 dB in the ultra-broad frequency range(3-40 GHz).The tensile strength and Young’s modulus of Ag-CNT film increase from 30.09±3.14 to 76.06±6.20 MPa(~253%)and from 1.12±0.33 to 8.90±0.97 GPa(~795%),respectively.Moreover,the Ag-CNT film exhibits excellent near-field shield-ing performance,which can effectively block wireless transmission.This innovative approach provides an effective route to further apply macroscopic CNT assemblies to future portable and wearable electronic devices.展开更多
Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass...Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical use.The root of these challenges lies in the mechanical instability of the material,which subsequently leads to the structural failure of the electrode.Here,we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles.This composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering method.Notably,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,resulting in an impressive areal capacity of 2.9 mA h cm^(-2)(736 mA h g^(-1)) and a steady cycle life(93% after 100cycles).Such outsta nding performance is paired with features appropriate for large-scale industrial production of silicon batteries,such as active mass loading of at least 3.9 mg cm^(-2),a high-tap density electrode material of 1.68 g cm^(-3)(secondary clusters:1.12 g cm^(-3)),and a production yield of up to 1 kg per day.展开更多
To study the thermal decomposition of Al/Zr H_(2)/PTFE with different Al particle size as well as mechanical strength and impact sensitivity under medium and low strain rates,molding-vacuum sintering was adopted to pr...To study the thermal decomposition of Al/Zr H_(2)/PTFE with different Al particle size as well as mechanical strength and impact sensitivity under medium and low strain rates,molding-vacuum sintering was adopted to prepare four groups of power materials and cylindrical specimens with different Al particle size.The active decomposition temperature of Zr H_(2) was obtained by TG-DSC,and the quasi-static mechanics/reaction characteristics as well as the impact sensitivity of the specimen were studied respectively by quasi-static compression and drop-hammer test.The results show that the yield strength of the material decreased with the increase of the Al particle size,while the compressive strength,failure strain and toughness increased first and then decreased,which reached the maximum values of 116.61 MPa,191%,and 119.9 MJ/m respectively when the Al particle size is 12-14 mm because of particle size grading.The specimens with the highest strength and toughness formed circumferential open cracks and reacted partly when pressed.Those with developmental cracks formed inside did not react.It is considered that fracture of specimens first triggered initial reaction between Al and PTFE to release an amount of heat.Then ZrH_(2) was activated and decomposed,and participated in subsequent reaction to generate Zr C.The impact sensitivity of the specimens decreased with the increase of Al particle size.展开更多
This work aims at designing a set of curing pressure routes to produce laminates with various void contents. The effects of various consolidation pressures resulting in different void contents on mechanical strength o...This work aims at designing a set of curing pressure routes to produce laminates with various void contents. The effects of various consolidation pressures resulting in different void contents on mechanical strength of carbon/epoxy laminates have been examined. Characterization of the voids, in terms of void volume fraction, void distribution, size, and shape, was performed by standard test, ultrasonic inspection and metallographic analysis. The interlaminar shear strength was measured by the short-beam method. An empirical model was used to predict the strength vs porosity. The predicted strengths conform well with the experimental data and voids were found to be uniformly distributed throughout the laminate.展开更多
Thermal insulation is an important indicator to evaluate the construction material in cold region engineering.As we know,adding the industrial waste as lightweight aggregate or creating the pore inside the cement-base...Thermal insulation is an important indicator to evaluate the construction material in cold region engineering.As we know,adding the industrial waste as lightweight aggregate or creating the pore inside the cement-based composite could make the texture loose,and the thermal insulating capacity of the material would be improved with this texture.Using these methods,the industrial by-product and engineering waste could be cycled in an efficient way.Moreover,after service the fragmented cement composites paste could be used as aggregate in the thermal insulating concrete again.While the porous texture is not favorable for the mechanical strength and long-term durability in a cold environment.To balance the above three requirements from two opposite directions,different processing methods were applied to create the thermal insulation concrete/mortar.Firstly,the organic/inorganic lightweight aggregate,including the Expanded Polystyrene(EPS),Expanded Perlite(EP),and Ceramsite(CRMST)particles,were applied to create the Lightweight Aggregate Concrete(LWAC).As the comparative tests,the expanded Superabsorbent Polymer(SAP)hydrogel and Air-Entraining Agent(AEA)were also introduced to create the porous mortar.The above concrete/mortar was tested in the normal state and under the Freeze-Thaw cycle to explore the engineering performance in cold regions.During the experimenting process,the thermal insulation,mechanical strength,and frost resistance of these cement-based composites were investigated,and an optimal thermal insulation concrete/mortar was determined.展开更多
An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs (phase change materials) produced by vacuum impregnation process between paraffin (PCMs) and fly ash part...An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs (phase change materials) produced by vacuum impregnation process between paraffin (PCMs) and fly ash particles. DSC (differential scanning calorimeter) has been used to determine the thermal properties of latent heat of melting and heat capacity for composite PCMs. Vacuum impregnation pressure of 40 in.Hg, paraffin melting temperature of 90℃, vacuum time and impregnation time of paraffin of 30 min are the optimum condition of composite PCMs productions. The values of latent heat of melting and heat capacity are 74.00 J/g and 15.726 J/g.℃ for composite PCMs that produces by the optimum condition in vacuum impregnation process. Increasing the amount of composite PCMs replacing for cement in mortars causes the compressive strength, flexural strength and tensile strength reduction. Compressive strength, flexural strength and tensile strength of mortar with and without composite PCMs can be increased by the longer time of water curing for mortar specimens. Thermal conductivity (k) of mortar cement is reduced by increasing the amount of composite PCMs which replaced for cement in mortar plate compositions. Composite PCMs have the efficiency for thermal energy insulation when incorporated into the buildings. Therefore, this property of paraffin/fly ash composites PCMs can reduce the energy consumption for temperature control in the buildings.展开更多
Finding a real thermoelectric(TE)material that excels in various aspects of TE performance,mechanical properties,TE power generation,and cooling is challenging for its commercialization.Herein,we report a novel multif...Finding a real thermoelectric(TE)material that excels in various aspects of TE performance,mechanical properties,TE power generation,and cooling is challenging for its commercialization.Herein,we report a novel multifunctional Ge0.78Cd0.06Pb0.1Sb0.06Te material with excellent TE performance and mechanical strength,which is utilized to construct candidate TE power generation and cooling devices near room temperature.Specifically,the effectiveness of band convergence,combined with optimized carrier concentration and electronic quality factor,distinctly boosts the Seebeck coefficient,thus greatly improving the power factor.Advanced electron microscopy observation indicates that complex multi-scale hierarchical structures and strain field distributions lead to ultra-low lattice thermal conductivity,and also effectively enhance mechanical properties.High ZT0.6 at 303 K,average ZTave1.18 from 303 to 553 K,and Vickers hardness of200 Hv in Ge0.78Cd0.06Pb0.1Sb0.06Te are obtained synchronously.Particularly,a 7-pair TE cooling device with a maximumΔT of45.9 K at Th=328 K,and a conversion efficiency of5.2%at Th=553 K is achieved in a single-leg device.The present findings demonstrate a unique approach to developing superior multifunctional GeTe-based alloys,opening up a promising avenue for commercial applications.展开更多
It is hard to get a high-strength La(Fe,Si)_(13)-based hydrides owing to the brittle feature of hydrides.In this work,we fabricated the La_(0.8)Ce_(0.2)Fe_(11.51)Mn_(0.19)Si_(1.3)plates through hot pressing at 1323 K ...It is hard to get a high-strength La(Fe,Si)_(13)-based hydrides owing to the brittle feature of hydrides.In this work,we fabricated the La_(0.8)Ce_(0.2)Fe_(11.51)Mn_(0.19)Si_(1.3)plates through hot pressing at 1323 K for various time.Subsequently,the saturated hydrogenization is achieved at 593 K in H_2 atmosphere of 0.13 MPa for 210 min.The microstructure and magnetocaloric properties were investigated by an X-ray diffractometer,a scanning electron microscope and the Versa-Lab.Under magnetic fields of 0-2 T,the maximal volumetric entropy change is 91.4 mJ/(cm^(3)·K)at 297 K for the hydride plates.The hydride plate simultaneously has excellent mechanical properties with the maximum bending strength of 213 MPa,which suggest that the hot pressing followed by hydrogenation could be an effective route of fabricating La(Fe,Si)_(13)-based hydrides for the potential application in the magnetic refrigerator.展开更多
Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength ...Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.展开更多
The high porosity and interconnectivity of scaffolds are critical for nutrient transmission in bone tis-sue engineering but usually lead to poor mechanical properties.Herein,a novel method that combines acid etching(A...The high porosity and interconnectivity of scaffolds are critical for nutrient transmission in bone tis-sue engineering but usually lead to poor mechanical properties.Herein,a novel method that combines acid etching(AE)with selective laser sintering(SLS)and reaction bonding(RB)of Al particles is pro-posed to realize highly improved porosity,interconnectivity,mechanical strength,and in vitro bioactivity in 3D Al_(2)O_(3) scaffolds.By controlling the oxidation and etching behaviors of Al particles,a tunable hol-low spherical feature can be obtained,which brings about the distinction in compressive response and fracture path.The prevention of microcrack propagation on the in situ formed hollow spheres results in unique near elastic buckling rather than traditional brittle fracture,allowing an unparalleled compressive strength of 3.72±0.17 MPa at a high porosity of 87.7%±0.4%and pore interconnectivity of 94.7%±0.4%.Furthermore,scaffolds with an optimized pore structure and superhydrophilic surface show excellent cell proliferation and adhesion properties.Our findings offer a promising strategy for the coexistence of out-standing mechanical and biological properties,with great potential for tissue engineering applications.展开更多
This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was conso...This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS material.The main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion resistance.Both materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,respectively.The corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SLM one and comparable to the conventional extruded material.The digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM material.On the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.展开更多
Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanica...Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanical properties of matrix materials with different mass ratio of resin and stabilizer(MRRS)were investigated systematically.The influences of MRRS on interface bonding strength of Mo fiber-matrix,wettability and mechanical strength of GPC were discussed,respectively,and the theoretical calculation result of MRRS k was obtained,with the optimal value of k=4.When k=4,tensile strength,tensile strain and fracture stress of the cured resin achieve the maximum values.But for k=7,the corresponding values reach the minimum.With the increase of MRRS k,surface free energy of the cured resin first increases and then decreases,while contact angles between Mo sample and matrix have displayed the opposite trend.Wettability of resin to Mo fiber is the best at k=4.Pulling load of Mo fiber and interface bonding strength appear the maximum at k=4,followed by k=5,k=3 the third,and k=7 the minimum.When k=4,mechanical properties of Mo fiber-reinforced GPC are optimal,which is consistent with the result of theoretical calculation.This study is of great significance to get better component formulas of Mo fiber reinforced GPC and to improve its application in machine tools.展开更多
The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential pollution.Utilizing CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this ma...The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential pollution.Utilizing CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural surroundings.This study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal elements.Microscopic examination via scanning electron microscopy(SEM)is employed to elucidate the underlying mechanisms.The results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,respectively.The DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured MS.Furthermore,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,respectively.The electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic relationship.The CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,respectively.The reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,respectively.Overall,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.展开更多
The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechani...The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.展开更多
With high water content(~90 wt%) and significantly improved mechanical strength(~MPa),double network(DN) hydrogels have emerged as promising biomaterials with widespread applications in biomedicine.In recent years,D...With high water content(~90 wt%) and significantly improved mechanical strength(~MPa),double network(DN) hydrogels have emerged as promising biomaterials with widespread applications in biomedicine.In recent years,DN hydrogels with extremely high mechanical strength have achieved great advance,and scientists have designed a series of natural and biomimetic DN hydrogels with novel functions including low friction,low wear,mechanical anisotropy and cell compatibility.These advances have also led to new design of biocompatible DN hydrogels for regeneration of tissues such as cartilage.In this paper,we reviewed the strategies of designing high-strength DN hydrogel and analyzed the factors that affect DN hydrogel properties.We also discussed the challenges and future development of the DN hydrogel in view of its potential as biomaterials for their biomedical applications.展开更多
A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pr...A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pressure drying without solvent exchange,and carbonization.The microstructure and network strength of CAs were tailored by adju sting the catalyst concentration([resorcinol]/[sodium carbonate] in the range of 300-2000),water content([deionized water]/[resorcinol] equals to 17 and 24,respectively),and gelation temperature(Tgel in the range of 30-90℃).Resultantly,the CAs with a wide range of density(0.30-1.13 g/cm3),high specific surface area(465-616 m2/g),high compressive strength(6.5-147.4 MPa)and low thermal conductivity(0.065-0.120 W·m-1 K-1) were obtained in this work.Moreover,the largesized CAs(100×100×20 mm3) can also be prepared by this method since the formed robust skeleton network can resist shrinkage/collapse of pore structure and prevent cracking during drying.The improved mechanical strength and monolithic forming abilities could be mainly attributed to the uniform arrangement of carbon particles and pores,fine particle size,abundant network structure and enhanced particle neck.展开更多
Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with flexibility,easy processability,low cost and especially strong ability to dissolve lithium salts have been regarded as promising alternatives to tradi...Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with flexibility,easy processability,low cost and especially strong ability to dissolve lithium salts have been regarded as promising alternatives to traditional flammable liquid electrolytes in next-generation highsafety and high-energy-density lithium metal batteries.However,the inferior mechanical strength and thermostability of PEO-based SPEs will raise the lithium dendritic penetration issue,further leading to the short circuit in batteries.In this work,aiming at enhancing the interfacial stability against Li dendrites of PEO-based SPEs,poly(mphenylene isophthalamide)(PMIA)is introduced as a reinforcing phase for the rational design of PEO/PMIA composite electrolyte.Impressively,PMIA chain with meta-type benzene-amide linkages significantly improves the mechanical strength(1.60 MPa),thermal stability(260℃)and ability to inhibit the growth of lithium dendrites(>300 h at 0.1 mA·cm^(-2))of SPEs.Meanwhile,allsolid-state LiFePO_(4)‖PEO/PMlA‖Li cell demonstrates superior electrochemical performance in terms of high specific capacity(159.1 mAh·g^(-1)),remarkable capacity retention(82.2%after 200 cycles at 0.5 C)and excellent safety characteristics.No burning or explosion occurs under pressing,bending and cutting conditions.This work opens a new door in developing high-performance PEObased electrolytes for advanced all-solid-state lithium metal batteries.展开更多
The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient perform-ance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are review...The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient perform-ance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and ad-vancement.展开更多
A fundamental step in the production of an industrial catalyst is its crushing strength assessment. Limited literature exists in which the strength reliability of supported catalysts is investigated from production to...A fundamental step in the production of an industrial catalyst is its crushing strength assessment. Limited literature exists in which the strength reliability of supported catalysts is investigated from production to their application in a reactor. In this work, cylindrical supports were prepared by pelletizing high poros- ity γ-alumina powder, and Cu-Znf/γ-Al2O3 catalysts were prepared by impregnation of the pelletized γ-alumina supports with an aqueous solution of copper and zinc nitrates. The support-forming variables, such as binder concentration, compaction pressure, calcination temperature, and drying procedure were investigated. The Weibull method was used to analyze the crushing strength data of the supports, and the fresh and used catalysts before and after the low-temperature water gas shift reaction. Support formation at a 50 wt% binder concentration, 1148 MPa compaction pressure, 500 ℃ calcination temperature, and rapid drying (100 ℃, 8 h) led to the maximum support mechanical reliability. The most reliable catalyst with respect to simultaneous appropriate catalytic performance and mechanical strength was prepared from a support with the lowest mean crushing strength (26.25 MPa). This work illustrates the impor- tance of the Weibull modulus as a useful mechanical reliability index in manufacturing a supported solid catalyst.展开更多
This work investigated the effect of sole yttrium and neodymium alloying on the microstructure formation during severe plastic deformation by equal channel angular pressing(ECAP) and an impact on the mechanical streng...This work investigated the effect of sole yttrium and neodymium alloying on the microstructure formation during severe plastic deformation by equal channel angular pressing(ECAP) and an impact on the mechanical strength and corrosion resistance of binary Mg-3Y and Mg-3Nd alloys.The results are compared with a ternary Mg-4Y-3Nd alloy,which represents a simplified version of the commercially successful WE43 alloy.The extensive study comprises a thorough microstructural analysis performed by scanning and transmission electron microscopy,including electron backscatter diffraction and texture analysis performed by X-ray diffraction.It is shown that the presence of Nd primarily caused precipitation during the processing of the Mg-3Nd alloy,while Y remained dissolved in the magnesium matrix in the Mg-3Y alloy.This difference resulted in a significantly smaller average grain size in the Mg-3Y alloy(~0.77 nm) than in the Mg-3Nd alloy(~1.3 μm) after the final step of the processing and formation of a slightly different texture.Consequently,the composition and the processing affected the mechanical and corrosion properties of the investigated materials,measured by compression deformation tests,microhardness measurement,and electrochemical impedance spectroscopy.This study shows that the ECAP-processed W3 sample exhibits a surprisingly good combination of ultrafine-grain structure,weak crystallographic texture,high strength,and high corrosion resistance compared with the other investigated samples.These attributes make this material very interesting for utilisation in the industry and/or medicine.展开更多
基金The authors gratefully acknowledge financial support from the National Natural Science Foundation of China(52103090)the Natural Science Foundation of Guangdong Province(2022A1515011780)Autonomous deployment project of China National Key Laboratory of Materials for Integrated Circuits(NKLJC-Z2023-B03).
文摘The remarkable properties of carbon nanotubes(CNTs)have led to promising applications in the field of electromagnetic inter-ference(EMI)shielding.However,for macroscopic CNT assemblies,such as CNT film,achieving high electrical and mechanical properties remains challenging,which heavily depends on the tube-tube interac-tions of CNTs.Herein,we develop a novel strategy based on metal-organic decomposition(MOD)to fabricate a flexible silver-carbon nanotube(Ag-CNT)film.The Ag particles are introduced in situ into the CNT film through annealing of MOD,leading to enhanced tube-tube interactions.As a result,the electrical conductivity of Ag-CNT film is up to 6.82×10^(5) S m^(-1),and the EMI shielding effectiveness of Ag-CNT film with a thickness of~7.8μm exceeds 66 dB in the ultra-broad frequency range(3-40 GHz).The tensile strength and Young’s modulus of Ag-CNT film increase from 30.09±3.14 to 76.06±6.20 MPa(~253%)and from 1.12±0.33 to 8.90±0.97 GPa(~795%),respectively.Moreover,the Ag-CNT film exhibits excellent near-field shield-ing performance,which can effectively block wireless transmission.This innovative approach provides an effective route to further apply macroscopic CNT assemblies to future portable and wearable electronic devices.
基金supported by the National Research Foundation, Prime Minister’s Office, Singapore, under its Competitive Research Programme (CRP award number NRF-CRP22-2019-008)Medium-Sized Centre Programme (CA2DM)+1 种基金the Ministry of Education of Singapore, under its Research Centre of Excellence award to the Institute for Functional Intelligent Materials (I-FIM, Project No. EDUNC-33-18-279-V12)by the EDB Singapore, under its Space Technology Development Programme (S2219013-STDP)。
文摘Despite advancements in silicon-based anodes for high-capacity lithium-ion batteries,their widespread commercial adoption is still hindered by significant volume expansion during cycling,especially at high active mass loadings crucial for practical use.The root of these challenges lies in the mechanical instability of the material,which subsequently leads to the structural failure of the electrode.Here,we present a novel synthesis of a composite combining expanded graphite and silicon nanoparticles.This composite features a unique interlayer-bonded graphite structure,achieved through the application of a modified spark plasma sintering method.Notably,this innovative structure not only facilitates efficient ion and electron transport but also provides exceptional mechanical strength(Vickers hardness:up to658 MPa,Young's modulus:11.6 GPa).This strength effectively accommodates silicon expansion,resulting in an impressive areal capacity of 2.9 mA h cm^(-2)(736 mA h g^(-1)) and a steady cycle life(93% after 100cycles).Such outsta nding performance is paired with features appropriate for large-scale industrial production of silicon batteries,such as active mass loading of at least 3.9 mg cm^(-2),a high-tap density electrode material of 1.68 g cm^(-3)(secondary clusters:1.12 g cm^(-3)),and a production yield of up to 1 kg per day.
基金financial support from the National Natural Science Foundation of China(General Program.Grant No.51673213)the National Natural Science Foundation of China(Youth Science Foundation.Grant No.51803235)。
文摘To study the thermal decomposition of Al/Zr H_(2)/PTFE with different Al particle size as well as mechanical strength and impact sensitivity under medium and low strain rates,molding-vacuum sintering was adopted to prepare four groups of power materials and cylindrical specimens with different Al particle size.The active decomposition temperature of Zr H_(2) was obtained by TG-DSC,and the quasi-static mechanics/reaction characteristics as well as the impact sensitivity of the specimen were studied respectively by quasi-static compression and drop-hammer test.The results show that the yield strength of the material decreased with the increase of the Al particle size,while the compressive strength,failure strain and toughness increased first and then decreased,which reached the maximum values of 116.61 MPa,191%,and 119.9 MJ/m respectively when the Al particle size is 12-14 mm because of particle size grading.The specimens with the highest strength and toughness formed circumferential open cracks and reacted partly when pressed.Those with developmental cracks formed inside did not react.It is considered that fracture of specimens first triggered initial reaction between Al and PTFE to release an amount of heat.Then ZrH_(2) was activated and decomposed,and participated in subsequent reaction to generate Zr C.The impact sensitivity of the specimens decreased with the increase of Al particle size.
文摘This work aims at designing a set of curing pressure routes to produce laminates with various void contents. The effects of various consolidation pressures resulting in different void contents on mechanical strength of carbon/epoxy laminates have been examined. Characterization of the voids, in terms of void volume fraction, void distribution, size, and shape, was performed by standard test, ultrasonic inspection and metallographic analysis. The interlaminar shear strength was measured by the short-beam method. An empirical model was used to predict the strength vs porosity. The predicted strengths conform well with the experimental data and voids were found to be uniformly distributed throughout the laminate.
基金The research project was supported by the Natural Science Foundation of China(Grant Nos.51972209,41801033,41801043)Young doctor Foundation of Education Department of Gansu Province(2021QB-039)+1 种基金Basic Research Innovation Group of Gansu Province(20JR5RA478)Industrial Support Program of Higher Education of Gansu Province(2020C−40).
文摘Thermal insulation is an important indicator to evaluate the construction material in cold region engineering.As we know,adding the industrial waste as lightweight aggregate or creating the pore inside the cement-based composite could make the texture loose,and the thermal insulating capacity of the material would be improved with this texture.Using these methods,the industrial by-product and engineering waste could be cycled in an efficient way.Moreover,after service the fragmented cement composites paste could be used as aggregate in the thermal insulating concrete again.While the porous texture is not favorable for the mechanical strength and long-term durability in a cold environment.To balance the above three requirements from two opposite directions,different processing methods were applied to create the thermal insulation concrete/mortar.Firstly,the organic/inorganic lightweight aggregate,including the Expanded Polystyrene(EPS),Expanded Perlite(EP),and Ceramsite(CRMST)particles,were applied to create the Lightweight Aggregate Concrete(LWAC).As the comparative tests,the expanded Superabsorbent Polymer(SAP)hydrogel and Air-Entraining Agent(AEA)were also introduced to create the porous mortar.The above concrete/mortar was tested in the normal state and under the Freeze-Thaw cycle to explore the engineering performance in cold regions.During the experimenting process,the thermal insulation,mechanical strength,and frost resistance of these cement-based composites were investigated,and an optimal thermal insulation concrete/mortar was determined.
文摘An experimental investigation was conducted to study the efficiency of thermal insulation of composite PCMs (phase change materials) produced by vacuum impregnation process between paraffin (PCMs) and fly ash particles. DSC (differential scanning calorimeter) has been used to determine the thermal properties of latent heat of melting and heat capacity for composite PCMs. Vacuum impregnation pressure of 40 in.Hg, paraffin melting temperature of 90℃, vacuum time and impregnation time of paraffin of 30 min are the optimum condition of composite PCMs productions. The values of latent heat of melting and heat capacity are 74.00 J/g and 15.726 J/g.℃ for composite PCMs that produces by the optimum condition in vacuum impregnation process. Increasing the amount of composite PCMs replacing for cement in mortars causes the compressive strength, flexural strength and tensile strength reduction. Compressive strength, flexural strength and tensile strength of mortar with and without composite PCMs can be increased by the longer time of water curing for mortar specimens. Thermal conductivity (k) of mortar cement is reduced by increasing the amount of composite PCMs which replaced for cement in mortar plate compositions. Composite PCMs have the efficiency for thermal energy insulation when incorporated into the buildings. Therefore, this property of paraffin/fly ash composites PCMs can reduce the energy consumption for temperature control in the buildings.
基金support from the National Key Research and Development Program of China(Grant Nos.2018YFA0702100 and 2022YFB3803900)the National Natural Science Foundation of China(Grant No.11874394)+2 种基金the Sichuan University Innovation Research Program of China(Grant No.2020SCUNL112)the University Synergy Innovation Program of Anhui Province(No.GXXT-2020-003)Ruihuan Cheng,Chengliang Xia,and Yue Chen are grateful for the research computing facilities offered by ITS,HKU.
文摘Finding a real thermoelectric(TE)material that excels in various aspects of TE performance,mechanical properties,TE power generation,and cooling is challenging for its commercialization.Herein,we report a novel multifunctional Ge0.78Cd0.06Pb0.1Sb0.06Te material with excellent TE performance and mechanical strength,which is utilized to construct candidate TE power generation and cooling devices near room temperature.Specifically,the effectiveness of band convergence,combined with optimized carrier concentration and electronic quality factor,distinctly boosts the Seebeck coefficient,thus greatly improving the power factor.Advanced electron microscopy observation indicates that complex multi-scale hierarchical structures and strain field distributions lead to ultra-low lattice thermal conductivity,and also effectively enhance mechanical properties.High ZT0.6 at 303 K,average ZTave1.18 from 303 to 553 K,and Vickers hardness of200 Hv in Ge0.78Cd0.06Pb0.1Sb0.06Te are obtained synchronously.Particularly,a 7-pair TE cooling device with a maximumΔT of45.9 K at Th=328 K,and a conversion efficiency of5.2%at Th=553 K is achieved in a single-leg device.The present findings demonstrate a unique approach to developing superior multifunctional GeTe-based alloys,opening up a promising avenue for commercial applications.
基金the ISF-SFC Joint Research Program(51961145305(NSFC))the National Natural Science Foundation of China(5217119)+2 种基金the Key Research and Development Program of Shanxi Province(2021KWZ-12)the IMAR(Inner Mongolia Autonomous Region)Natural Science Foundation(2021MS05016)the Northern Rare Earth Project(BFXT-2021-D-0013)。
文摘It is hard to get a high-strength La(Fe,Si)_(13)-based hydrides owing to the brittle feature of hydrides.In this work,we fabricated the La_(0.8)Ce_(0.2)Fe_(11.51)Mn_(0.19)Si_(1.3)plates through hot pressing at 1323 K for various time.Subsequently,the saturated hydrogenization is achieved at 593 K in H_2 atmosphere of 0.13 MPa for 210 min.The microstructure and magnetocaloric properties were investigated by an X-ray diffractometer,a scanning electron microscope and the Versa-Lab.Under magnetic fields of 0-2 T,the maximal volumetric entropy change is 91.4 mJ/(cm^(3)·K)at 297 K for the hydride plates.The hydride plate simultaneously has excellent mechanical properties with the maximum bending strength of 213 MPa,which suggest that the hot pressing followed by hydrogenation could be an effective route of fabricating La(Fe,Si)_(13)-based hydrides for the potential application in the magnetic refrigerator.
基金supported by the Natural Science Foundation of Sichuan Province(Nos.2023YFG0096,2022NSFSC2008 and 2023NSFSC0442).
文摘Poly(m-phthaloyl-m-phenylenediamine)(PMIA)is promising as the separator in lithium-ion batteries(LIBs)for its excellent thermostability,insulation and self-extinguishing properties.However,its low mechanical strength and poor electrolyte affinity limit its application in LIBs.In this work,a new PMIA@polyacrylonitrile-polyvinylidene fluoride hexafluoropropylene-titanium dioxide(PMIA@PAN/PVDFHFP/TiO_(2))composite fibrous separator with a coaxial core-shell structure was developed by combining coaxial electrospinning,hot pressing,and heat treatment techniques.This separator not only inherits the exceptional thermostability of PMIA,showing no evident thermal shrinkage at 220 ℃,but also reveals improved mechanical strength(29.7 MPa)due to the formation of firm connections between fibers with the melted PVDF-HFP.Meanwhile,the massive polar groups in PVDF-HFP play a vital role in improving the electrolyte affinity,which renders the separator a high ionic conductivity of 1.36×10^(-3)s/cm.Therefore,the LIBs with PMIA@PAN/PVDF-HFP/TiO_(2)separators exhibited excellent cycling and rate performance at 25℃,and a high capacity retention rate(76.2%)at 80℃for 200 cycles at 1 C.Besides,the lithium metal symmetric battery assembled by the separator showed a small overpotential,indicating that the separator had a role in inhibiting lithium dendrites.In short,the PMIA@PAN/PVDF-HFP/TiO_(2) separator possesses a wide application prospect in the domain of LIBs.
文摘The high porosity and interconnectivity of scaffolds are critical for nutrient transmission in bone tis-sue engineering but usually lead to poor mechanical properties.Herein,a novel method that combines acid etching(AE)with selective laser sintering(SLS)and reaction bonding(RB)of Al particles is pro-posed to realize highly improved porosity,interconnectivity,mechanical strength,and in vitro bioactivity in 3D Al_(2)O_(3) scaffolds.By controlling the oxidation and etching behaviors of Al particles,a tunable hol-low spherical feature can be obtained,which brings about the distinction in compressive response and fracture path.The prevention of microcrack propagation on the in situ formed hollow spheres results in unique near elastic buckling rather than traditional brittle fracture,allowing an unparalleled compressive strength of 3.72±0.17 MPa at a high porosity of 87.7%±0.4%and pore interconnectivity of 94.7%±0.4%.Furthermore,scaffolds with an optimized pore structure and superhydrophilic surface show excellent cell proliferation and adhesion properties.Our findings offer a promising strategy for the coexistence of out-standing mechanical and biological properties,with great potential for tissue engineering applications.
基金supported by the Czech Science Foundation under project no.22-21122JPartial financial support from the Ministry of Health of the Czech Republic under the grant Nr.20-08-00150+2 种基金partial financial support from the Charles University Grant Agency under project number 389422partial financial support from the Science Grant Agency of the Slovak Republic through project No.1/0153/21faculty specific research project FSI-S-23-8340.
文摘This work explored possibilities of biodegradable magnesium alloy Mg-3Y preparation by two modern powder metallurgy techniques–spark plasma sintering(SPS)and selective laser melting(SLM).The powder material was consolidated by both methods utilising optimised parameters,which led to very low porosity(∼0.3%)in the SLM material and unmeasurably low porosity in the SPS material.The main aim of the study was the thorough microstructure characterisation and interrelation between the microstructure and the functional properties,such as mechanical strength,deformability,and corrosion resistance.Both materials showed comparable strength of∼110 MPa in tension and compression and relatively good deformability of∼9%and∼21%for the SLM and SPS materials,respectively.The corrosion resistance of the SPS material in 0.1 M NaCl solution was superior to the SLM one and comparable to the conventional extruded material.The digital image correlation during loading and the cross-section analysis of the corrosion layers revealed that the residual porosity and large strained grains have the dominant negative effect on the functional properties of the SLM material.On the other hand,one of the primary outcomes of this study is that the SPS consolidation method is very effective in the preparation of the W3 biodegradable alloy,resulting in material with convenient mechanical and degradation properties that might find practical applications.
基金Fouded by the National Natural Science Foundation of China(No.51175308)the National Science and Technology Major Project of China(No.2012ZX04010032)。
文摘Because inferior mechanical strength of granite polymer composite(GPC)has become the main drawback limiting its application and popularization,Mo fibers were added into(GPC)to improve its mechanical strength.Mechanical properties of matrix materials with different mass ratio of resin and stabilizer(MRRS)were investigated systematically.The influences of MRRS on interface bonding strength of Mo fiber-matrix,wettability and mechanical strength of GPC were discussed,respectively,and the theoretical calculation result of MRRS k was obtained,with the optimal value of k=4.When k=4,tensile strength,tensile strain and fracture stress of the cured resin achieve the maximum values.But for k=7,the corresponding values reach the minimum.With the increase of MRRS k,surface free energy of the cured resin first increases and then decreases,while contact angles between Mo sample and matrix have displayed the opposite trend.Wettability of resin to Mo fiber is the best at k=4.Pulling load of Mo fiber and interface bonding strength appear the maximum at k=4,followed by k=5,k=3 the third,and k=7 the minimum.When k=4,mechanical properties of Mo fiber-reinforced GPC are optimal,which is consistent with the result of theoretical calculation.This study is of great significance to get better component formulas of Mo fiber reinforced GPC and to improve its application in machine tools.
基金supported by Hebei Province Higher Education Science and Technology Research Project(No.ZC2024031).
文摘The presence of toxic elements in manganese slag(MSG)poses a threat to the environment due to potential pollution.Utilizing CO_(2) curing on MS offers a promising approach to immobilize toxic substances within this material,thereby mitigating their release into the natural surroundings.This study investigates the impact of CO_(2) cured MS on various rheological parameters,including slump flow,plastic viscosity(η),and yield shear stress(τ).Additionally,it assesses flexural and compressive strengths(f_(t) and f_(cu)),drying shrinkage rates(DSR),durability indicators(chloride ion migration coefficient(CMC),carbonization depth(CD)),and the leaching behavior of heavy metal elements.Microscopic examination via scanning electron microscopy(SEM)is employed to elucidate the underlying mechanisms.The results indicate that CO_(2) curing significantly enhances the slump flow of ultra-high performance concrete(UHPC)by up to 51.2%.Moreover,it reduces UHPC’sηandτby rates ranging from 0%to 52.7%and 0%to 40.2%,respectively.The DSR exhibits a linear increase corresponding to the mass ratio of CO_(2) cured MS.Furthermore,CO_(2) curing enhances both f_(t) and f_(cu) of UHPC by up to 28.7%and 17.6%,respectively.The electrical resistance is also improved,showing an increase of up to 53.7%.The relationship between mechanical strengths and electrical resistance follows a cubic relationship.The CO_(2) cured MS demonstrates a notable decrease in the CMC and CD by rates ranging from 0%to 52.6%and 0%to 26.1%,respectively.The reductions of leached chromium(Cr)and manganese(Mn)are up to 576.3%and 1312.7%,respectively.Overall,CO_(2) curing also enhances the compactness of UHPC,thereby demonstrating its potential to improve both mechanical and durability properties.
文摘The mining process involves drilling and excavation, resulting in the production of waste rock and tailings. The waste materials are then removed and stored in designated areas. This study aims to evaluate the mechanical strength and the environmental and economic impact of using Coltan Mining Waste (CMW) as a substitute for aggregates in concrete and mortar production. To achieve this, the CMW needs to be characterised. The Dreux Gorisse method was primarily used to produce concrete with a strength of 20 MPa at 28 days. The mortars, on the other hand, were formulated according to the NF P 18-452 standard. The environmental impact of using CMW as substitutes for natural aggregates in the production of concrete and mortar was analysed using SimaPro software. The results showed that mortars and concrete made with CMW have comparable compressive strengths to the reference mortar and concrete;reduce the negative impact on ecosystem quality, human health, resources, and climate change. It has also been shown that the substitution of aggregates by CMW reduces the cost of concrete and mortar as a function of the distance from the aggregate footprint.
基金supported by the National Natural Science Foundation of China (Grant Nos. 51073127,51173144 )the Higher School Specialized Research Fund for the Doctoral Program FundingIssue (Grant No. 20100201110040 )+1 种基金the Operation Expenses for Universities’ Basic Scientific Research of Central Authorities (Grant No. 0109-08140018 )the New Research Support Project (Grant No. 08141001) from Xi’an Jiaotong University,P. R. China
文摘With high water content(~90 wt%) and significantly improved mechanical strength(~MPa),double network(DN) hydrogels have emerged as promising biomaterials with widespread applications in biomedicine.In recent years,DN hydrogels with extremely high mechanical strength have achieved great advance,and scientists have designed a series of natural and biomimetic DN hydrogels with novel functions including low friction,low wear,mechanical anisotropy and cell compatibility.These advances have also led to new design of biocompatible DN hydrogels for regeneration of tissues such as cartilage.In this paper,we reviewed the strategies of designing high-strength DN hydrogel and analyzed the factors that affect DN hydrogel properties.We also discussed the challenges and future development of the DN hydrogel in view of its potential as biomaterials for their biomedical applications.
基金supported by the Major Program of Aerospace Advanced Manufacturing Technology Research Foundation of NSFC and CASC, China Grant No. U1537204National Natural Science Foundation of China Grant No. 51802313 and 51902315+2 种基金National Science and Technology Major Project (2017-VI-0020-0093)Research Fund of Youth Innovation Promotion Association of CAS, China Grant No. 2014171National Key R&D Program of China Grant No. 2018YFF01013600。
文摘A simple,fast and cost-effective method for monolithic carbon aerogels(CAs) preparation was proposed through sol-gel polycondensation of resorcinol with fo rmaldehyde in a basic aqueous solution followed by ambient pressure drying without solvent exchange,and carbonization.The microstructure and network strength of CAs were tailored by adju sting the catalyst concentration([resorcinol]/[sodium carbonate] in the range of 300-2000),water content([deionized water]/[resorcinol] equals to 17 and 24,respectively),and gelation temperature(Tgel in the range of 30-90℃).Resultantly,the CAs with a wide range of density(0.30-1.13 g/cm3),high specific surface area(465-616 m2/g),high compressive strength(6.5-147.4 MPa)and low thermal conductivity(0.065-0.120 W·m-1 K-1) were obtained in this work.Moreover,the largesized CAs(100×100×20 mm3) can also be prepared by this method since the formed robust skeleton network can resist shrinkage/collapse of pore structure and prevent cracking during drying.The improved mechanical strength and monolithic forming abilities could be mainly attributed to the uniform arrangement of carbon particles and pores,fine particle size,abundant network structure and enhanced particle neck.
基金financially supported by the Natural Science Foundation of Zhejiang Province(Nos.LY21E020005,2022C01173 and LD22E020006)China Postdoctoral Science Foundation(Nos.2020M671785 and 2020T130597)+1 种基金the National Natural Science Foundation of China(Nos.U20A20253,51777194,21972127 and 21905249)Zhejiang Provincial Special Support Program for High-level Talents(No.2020R51004)。
文摘Polyethylene oxide(PEO)-based solid polymer electrolytes(SPEs)with flexibility,easy processability,low cost and especially strong ability to dissolve lithium salts have been regarded as promising alternatives to traditional flammable liquid electrolytes in next-generation highsafety and high-energy-density lithium metal batteries.However,the inferior mechanical strength and thermostability of PEO-based SPEs will raise the lithium dendritic penetration issue,further leading to the short circuit in batteries.In this work,aiming at enhancing the interfacial stability against Li dendrites of PEO-based SPEs,poly(mphenylene isophthalamide)(PMIA)is introduced as a reinforcing phase for the rational design of PEO/PMIA composite electrolyte.Impressively,PMIA chain with meta-type benzene-amide linkages significantly improves the mechanical strength(1.60 MPa),thermal stability(260℃)and ability to inhibit the growth of lithium dendrites(>300 h at 0.1 mA·cm^(-2))of SPEs.Meanwhile,allsolid-state LiFePO_(4)‖PEO/PMlA‖Li cell demonstrates superior electrochemical performance in terms of high specific capacity(159.1 mAh·g^(-1)),remarkable capacity retention(82.2%after 200 cycles at 0.5 C)and excellent safety characteristics.No burning or explosion occurs under pressing,bending and cutting conditions.This work opens a new door in developing high-performance PEObased electrolytes for advanced all-solid-state lithium metal batteries.
文摘The mechanical strength of solid catalysts is one of the key parameters for reliable and efficient perform-ance of a fixed bed reactor. Some recent developments and their basic mechanics within this context are reviewed. The main concepts discussed are brittle fracture which leads to the mechanical failure of the catalyst pellets, measurement and statistical properties of the catalyst strength data, and mechanical reliability of the catalyst pellets and their packed bed. The scientific basis for the issues on the catalyst mechanical properties calls yet for further elucidation and ad-vancement.
文摘A fundamental step in the production of an industrial catalyst is its crushing strength assessment. Limited literature exists in which the strength reliability of supported catalysts is investigated from production to their application in a reactor. In this work, cylindrical supports were prepared by pelletizing high poros- ity γ-alumina powder, and Cu-Znf/γ-Al2O3 catalysts were prepared by impregnation of the pelletized γ-alumina supports with an aqueous solution of copper and zinc nitrates. The support-forming variables, such as binder concentration, compaction pressure, calcination temperature, and drying procedure were investigated. The Weibull method was used to analyze the crushing strength data of the supports, and the fresh and used catalysts before and after the low-temperature water gas shift reaction. Support formation at a 50 wt% binder concentration, 1148 MPa compaction pressure, 500 ℃ calcination temperature, and rapid drying (100 ℃, 8 h) led to the maximum support mechanical reliability. The most reliable catalyst with respect to simultaneous appropriate catalytic performance and mechanical strength was prepared from a support with the lowest mean crushing strength (26.25 MPa). This work illustrates the impor- tance of the Weibull modulus as a useful mechanical reliability index in manufacturing a supported solid catalyst.
基金supported by Czech Science Foundation under project no. 22-21122 JPartial financial support from the Ministry of Health of the Czech Republic under the grant Nr.20-08-0015A+1 种基金partial financial support from the Charles University Grant Agency under project numbers 389422 and 1172120, respectivelypartial financial support from the Ministry of Transport and Construction of the Slovak Republic,OPII,grant No. ITMS:313011AFG4, co-financed by ERDF。
文摘This work investigated the effect of sole yttrium and neodymium alloying on the microstructure formation during severe plastic deformation by equal channel angular pressing(ECAP) and an impact on the mechanical strength and corrosion resistance of binary Mg-3Y and Mg-3Nd alloys.The results are compared with a ternary Mg-4Y-3Nd alloy,which represents a simplified version of the commercially successful WE43 alloy.The extensive study comprises a thorough microstructural analysis performed by scanning and transmission electron microscopy,including electron backscatter diffraction and texture analysis performed by X-ray diffraction.It is shown that the presence of Nd primarily caused precipitation during the processing of the Mg-3Nd alloy,while Y remained dissolved in the magnesium matrix in the Mg-3Y alloy.This difference resulted in a significantly smaller average grain size in the Mg-3Y alloy(~0.77 nm) than in the Mg-3Nd alloy(~1.3 μm) after the final step of the processing and formation of a slightly different texture.Consequently,the composition and the processing affected the mechanical and corrosion properties of the investigated materials,measured by compression deformation tests,microhardness measurement,and electrochemical impedance spectroscopy.This study shows that the ECAP-processed W3 sample exhibits a surprisingly good combination of ultrafine-grain structure,weak crystallographic texture,high strength,and high corrosion resistance compared with the other investigated samples.These attributes make this material very interesting for utilisation in the industry and/or medicine.