The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring *** extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compare...
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The Ti_(p)/ZX60 composites with different Ti_(p) contents were prepared by semi-solid stirring *** extrusion,the microstructure,work hardening and softening behavior of the Ti_(p)/ZX60 composites were analyzed compared with the ZX60(Mg-6Zn-0.2Ca)*** results showed that the addition of Ti_(p) could not only promote the nucleation of dynamic recrystallized(DRXed)grains,but also be propitious to the refinement of DRXed *** increasing Ti_(p) content,the size of DRXed grains decreased accompanied with increasing volume fraction of DRXed *** the Ti_(p) content increased to 15 vol.%,the average size and volume fraction of DRXed grains reached to~0.32μm and 93.2%,***,both the strength and elongation were improved by the addition of Ti_(p).With increasing content of Ti_(p),a substantial increase in the strength was achieved with little change in the ***,the elongation decreased sharply when the Ti_(p) content further increased to 15 vol.%.The addition of Ti_(p) led to an increase in the work hardening rate,which gradually increased with increasing Ti_(p) ***,the softening rate did not demonstrate the same tendency with increasing Ti_(p) *** the conventional ceramic particles,the Ti_(p) can be deformed in coordination with the matrix alloy,which imparted a higher softening rate to the matrix *** though the softening rate improved as the Ti_(p) content increased from 5 to 10 vol.%,it dropped deeply as the Ti_(p) content increased to 15 vol.%owing to the fracture of Ti_(p) during extrusion.
Functional carbonaceous materials with controllable morphology,low apparent density,large surface area,and high porosity starting from natural precursors using environmentally friendly processes are an ap-pealing topi...
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Functional carbonaceous materials with controllable morphology,low apparent density,large surface area,and high porosity starting from natural precursors using environmentally friendly processes are an ap-pealing topic in the electromagnetic wave(EMW)*** this work,renewable pine woods with ordered pore channels are selected to load highly dispersed CoFe alloy nanoparticles formed by in-situ pyrolysis reaction between Fe_(3)O_(4)nanospheres and ZIF-67 *** constructed three-dimensional(3D)porous CWA-CoFe-NC aerogel inherits the characteristics of highly dispersed small CoFe alloy nanopar-ticles,porous carbon aerogel with rectangular honeycomb-like structure,and abundant N ***,CWA-CoFe-NC aerogel achieves an excellent EMW absorption performance with reflection loss(RL)values of−61.6 and−58.2 dB at matching thicknesses of 3.7 and 1.2 mm,*** from the reasonable design of the composite structure and composition,3D porous aerogel also enables great potential for multifunctional ***,good lightweight and mechanical properties are realized in the CWA-CoFe-NC aerogels due to their ordered pore channels and abundant rectangular ***,good flame retardant performance can ensure the serviceability of the target device in high/low-temperature *** addition,CWA-CoFe-NC aerogels show good thermal stability and thermal management *** work provides a novel and effective method for the prepa-ration of lightweight,high-performance,and multifunctional EMW absorbers.
Boron suboxide(B_(6)O)is recognized as a superhard material with a low mass density,high resistance to chemical wear,and excellent wear *** its desirable properties,the limited fracture tough-ness of B_(6)O restricts ...
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Boron suboxide(B_(6)O)is recognized as a superhard material with a low mass density,high resistance to chemical wear,and excellent wear *** its desirable properties,the limited fracture tough-ness of B_(6)O restricts its application in industrial *** study presents the structural and me-chanical characterization of B_(6)O-SiC nanocomposites,which were synthesized via a high-pressure high-temperature sintering process of B_(6)O powders and SiC *** sintering process induced fragmen-tation of SiC whiskers,resulting in the homogenous distribution of SiC fragments within the B_(6)O *** increase in SiC content was observed to decrease the composite’s hardness,while initially reducing then enhancing its *** nanocomposites containing 20 wt%and 30 wt%SiC whiskers exhibited significant improvements in fracture toughness,averaging 6.5 MPa m^(1/2)and 7.0 MPa m^(1/2),respectively-approximately threefold the toughness of polycrystalline B_(6)O-while sustaining high hardness values of 36.3 GPa and 35.6 GPa on *** analyses revealed that the composites’superior me-chanical performance is due to the presence of strong grain boundaries,as well as a high density of nan-otwins and stacking *** findings demonstrate a viable method for producing B_(6)O-based nanocom-posites with enhanced hardness and toughness,potentially expanding their industrial applicability.
The hot deformation behaviors of sulfur-containing gear steel 20MnCr5 containing three different contents of Nb and B(0,0.021%Nb,and 0.024%Nb-0.0022%B)were *** compression and tenssion tests were carried out by Gleebl...
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The hot deformation behaviors of sulfur-containing gear steel 20MnCr5 containing three different contents of Nb and B(0,0.021%Nb,and 0.024%Nb-0.0022%B)were *** compression and tenssion tests were carried out by Gleeble3800 at the austenite region from 850 to 1150℃and the adverse effects of Nb and B were analyzed by the fracture,microstructure and precipitate *** compression tests showed that the proportions of instable area in hot processing maps of 0.021%Nb and Nb-B steels were higher and the deformability of Nb free steel was *** tensile deformation experiments showed that the reduction areas of Nb free,0.021%Nb and Nb-B steels were 92%-99%,84%-98%and 67%-97%,*** addition of Nb or Nb and B inhibited the dynamic recrystallization during hot deformation,and consequently,more deformed grains were then formed in 0.021%Nb and Nb-B steels thus to obtain the microstructure with worse uniformity and then deteriorate the *** addition,the interaction between inclusions and microalloyed elements was also *** particles of 0.021%Nb and Nb-B steels dynamically precipitated during deformation and precipitated together with MnS thus to worsen the deformability,resulting in the decrease of reduction area.
The common problem of low strength-ductility matching prevails in near-αhigh-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)_(6)Si_(3) nanoprecip...
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The common problem of low strength-ductility matching prevails in near-αhigh-temperature titanium matrix composites(TMCs).In this work,the design strategy of ultrafine grains and dispersed(Ti,Zr)_(6)Si_(3) nanoprecipitates in the microstructure of TiB_(w)/nearα-Ti composites via low-temperature isothermal mul-tidirectional forging(IMDF),is expected to break the trade-offdilemma between strength and *** results show that with the decrease in the temperature of IMDF,the grain scale decreased from 0.98 to 0.59μm,and the location of silicide precipitation shifted from phase boundaries and grain boundaries toα-grain boundaries and intracrystalline *** experiments confirm that the local segregation of Si and the temperature of thermomechanical deformation are the key factors affecting the precipitation behavior of *** the decrease of the deformation temperature,the precipitation mechanism of silicides changes from a single diffusion-controlled precipitation to the coupling of two mechanisms,namely,elemental diffusion and dislocation-assisted nucleation,which facilitates the successive precip-itation of nanometer-sized silicides at the grain boundaries and in the inner *** ultimate ten-sile strength(UTS)and elongation of the composites were substantially increased after IMDF at 950 and 800℃,especially the excellent performance at 800℃,where the strength reached 1320.3 MPa and the elongation was 5.8%.The room and high-temperature strengthening and failure mechanisms of the com-posites are analyzed and discussed,and the yield strength(YS)increments provided by various strength-ening mechanisms at room temperature are quantified,aiming to provide a potential preparation strategy for the synergistic strengthening of near-αTMCs with ultrafine grains and nanoparticles.
Compared to single atom catalysts(SACs),the introduction of dual atom catalysts(DACs)has a significantly positive effect on improving the efficiency in the electrocatalytic nitrogen reduction reaction(NRR)which provid...
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Compared to single atom catalysts(SACs),the introduction of dual atom catalysts(DACs)has a significantly positive effect on improving the efficiency in the electrocatalytic nitrogen reduction reaction(NRR)which provides an environmental alternative to the Haber-Bosch ***,the research on the mechanism and strategy of designing bimetallic combinations for better performance is still in its early ***,based on"blocking and rebalance"mechanism,45 combinations of bimetallic pair dopedα-phosphorus carbide(TM_(A)TM_(B)@PC)are investigated as efficient NRR catalysts through density functional theory and machine learning *** a multi-step screening,the combinations of TiV,TiFe,MnMo,and FeW exhibit highly efficient catalytic performance with significantly lower limiting potentials(-0.17,-0.18,-0.14,and-0.30 V,respectively).Excitingly,the limiting potential for CrMo and CrW combinations is 0 V,which are considered to be extremely suitable for the NRR *** mechanism of"blocking and rebalance"is revealed by the exploration of charge transfer for phosphorus atoms in electron blocking ***,the descriptorφis proposed with machine learning,which provides design strategies and accurate prediction for finding efficient *** work not only offers promising catalysts TM_(A)TM_(B)@PC for NRR process but also provides design strategies by presenting the descriptorφ.
The memory effect in a single-crystal spin glass (Cu0.92Mn0.08) has been measured using 1 Hz ac susceptibility techniques over a temperature range of 0.4–0.7Tg, and a model of the memory effect has been developed. A ...
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The memory effect in a single-crystal spin glass (Cu0.92Mn0.08) has been measured using 1 Hz ac susceptibility techniques over a temperature range of 0.4–0.7Tg, and a model of the memory effect has been developed. A double-waiting-time protocol is carried out where the spin glass is first allowed to age at a temperature below Tg, followed by a second aging at a lower temperature, Tw2, after it has fully rejuvenated. The model is based on calculating typical coincident growth of correlated regions at the two temperatures. It accounts for the absolute magnitude of the memory effect as a function of both waiting times and temperatures. The data can be explained by the memory loss being a function of the relative change in the correlated volume at the first waiting temperature because of the growth in the correlations at the second waiting temperature.
The electromigration reliability on Sn–10Bi solder joints is investigated and the performance is tried to be improved with trace Zn addition in solder by depressing the growth of interfacial intermetallic compounds(I...
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The electromigration reliability on Sn–10Bi solder joints is investigated and the performance is tried to be improved with trace Zn addition in solder by depressing the growth of interfacial intermetallic compounds(IMCs)under *** electromigration test was realized on Cu/solder/Cu linear specimens at a current density of 1.0×10^(4) A/cm^(2) with different stressing *** was found that Bi atoms in Cu/Sn-10Bi/Cu solder joint were driven towards anode side under current driving force and then accumulated at anode interface with current stressing time *** thickness and growth rate of Cu_(6)Sn_(5) IMCs at anode interface were obviously larger than those at cathode side due to polarity *** addition of 0.2 wt.%Zn inhibited the migration of Bi atoms during the electromigration process,and the composition of interfacial IMCs was transformed into Cu_(6)(Sn,Zn)_(5),which played as a diffusion barrier to effectively reduce the asymmetric growth of IMCs and the consumption of Cu substrate during electromigation.
Lithium metal batteries(LMBs)have been extensively investigated during the past decades because of their ultrahigh energy *** the increasing demand for energy density,however,the safety issue of LMBs has become a sign...
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Lithium metal batteries(LMBs)have been extensively investigated during the past decades because of their ultrahigh energy *** the increasing demand for energy density,however,the safety issue of LMBs has become a significant *** particular,localized areas of increased temperature(namely,hotspots)may be induced and even exacerbated within LMBs by uneven current distribution,internal short circuits,or inadequate heat dissipation,which significantly sacrifices battery safety and cycle ***,we report the rational design and fabrication of a fast thermal responsive separator capable of inhibiting the growth of lithium dendrites and mitigating thermal propagation,thereby reducing the risk of thermal *** as-achieved separator comprises both an electrospun membrane using a phase change material with superior thermal-storage ability and a thermally conductive modification layer of hexagonal boron nitride nanosheets with a fast heat-transfer *** is demonstrated that such a unique integration of heat conduction and heat storage enables the functional separator with attractive abilities to mitigate hotspots and inhibit the growth of lithium dendrites upon the cycling of ***,pouch cells with the thermal-responsive separator,as well as numerical simulations,verify much enhanced safety and cycle life of *** work may offer a new conceptual design of intelligent separators that acts as a functional unit encapsulated within a single cell to boost in-situ thermal management,which will help to develop high-safety and energy-dense LMBs.
The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condi...
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The welding arc,as a carrier for the conversion of electrical energy to thermal energy,has a direct impact on the quality of welding by its properties and *** the tungsten inert gas(TIG)welding process under the condition of Ar-He alternating gas supply,the arc is alternately converted between Ar arc and He arc with an alternating gas supply cycle,which has obvious arc change *** FLUENT software was used to numerically simulate the characteristics of the TIG arc under the condition of alternating gas supply,and the arc temperature field,arc pressure,electric potential and current density distribution under the condition of alternating gas supply were *** with the real-time data of arc pressure measured by the water-cooled copper plate with holes,it is proved that the TIG arc has obvious dynamic characteristics under the condition of Ar-He alternating gas *** unique dynamic TIG arc acts on the 5A06 aluminum alloy weld,causing the molten pool to stir,resulting in uniform microstructure and grain refinement at the weld,and thereby improving the mechanical properties of the welded joint.
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