To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting(HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HP...
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To understand the relationship between the process-microstructure-mechanical properties of the high-pressure die-casting(HPDC) AE44 magnesium alloy, 3D reconstruction and 2D characterization were carried out on the HPDC castings produced with different process parameters(low slow-shot speed, fast slow-shot speed, solidification pressure). Microstructural characterization revealed that the formation of shrinkage pores are closely related to ESCs, which were mainly controlled by the low slow-shot speed in shot sleeve(ESCs growth time) and fast slow-shot speed into the die cavity(distribution of ESCs). In addition, solidification pressure can significantly reduce the shrinkage porosity in the center by improving the feeding capacity of liquid metal. Tensile fracture revealed that the tearing ridge is mainly evolved from the slip band of ESCs. The quantity and distribution of ESCs determine the fracture mode of castings. The relationship between mechanical properties of castings and the morphology of ESCs and porosity is also statistically discussed.
Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin *** occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to create twin...
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Twinning is a deformation mechanism that creates three-dimensional(3D)twin domains through the migration of twin *** occurs via the nucleation and glide of twinning disconnections(TDs),which can pile up to create twin facets.A comprehensive under-standing of twin facets associated with 3D twins,including their atomic structures and energies,is crucial for understanding deformation *** this study,we propose a molecular statics/dynamics(MS/MD)approach to determine characteristic twin facets enclosing 3D non-equilibrium/equilibrium{1011}twin domains,which has been much less studied than the counterpart{1012}twin *** stability of different TD pile-up arrangement with varying line senses informs the morphology of 3D non-equilibrium twins,which are bounded by{1010}_(T)||{1013}_(M),{1011}_(T)||{0002}_(M)and{1013}_(T)||{1013}_(M)coherent facets associated with pile-up of edge TDs,and discrete non-edge TDs aligned along CTBs with their line senses parallel to<4513>,<1101>,<5416><2113>or<1012>*** of semi-coherent facets of equilibrium twins is accompanied by rearrangement of TDs around misfit dislocations.3D equilibrium{1011}twins may comprise{1011}_(T)||{0002}_(M),{1457}_(T)||{3419}_(M),{1657}_(T)||{5617}_(M),{1433}_(T)||{3413}_(M),{0110}_(T)||{0111}_(M)and{0221}_(T)||{0221}_(M)semi-coherent facets in<1210>,<4513>,<1101>,<5416>,<2113>and<1012>axes,respectively.
Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a *...
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Artificially controlling the solid-state precipitation in aluminum (Al) alloys is an efficient way to achieve well-performed properties,and the microalloying strategy is the most frequently adopted method for such a *** this paper,recent advances in lengthscale-dependent scandium (Sc) microalloying effects in Al-Cu model alloys are *** coarse-grained Al-Cu alloys,the Sc-aided Cu/Sc/vacancies complexes that act as heterogeneous nuclei and Sc segregation at the θ′-Al_(2)Cu/matrix interface that reduces interfacial energy contribute significantly to θ′*** grain size refinement to the fine/ultrafine-grained scale,the strongly bonded Cu/Sc/vacancies complexes inhibit Cu and vacancy diffusing toward grain boundaries,promoting the desired intragranular θ′*** nanocrystalline scale,the applied high strain producing high-density vacancies results in the formation of a large quantity of (Cu Sc,vacancy)-rich atomic complexes with high thermal stability,outstandingly improving the strength/ductility synergy and preventing the intractable low-temperature *** review recommends the use of microalloying technology to modify the precipitation behaviors toward better combined mechanical properties and thermal stability in Al alloys.
Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity up...
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Anode active materials involving transition metal oxides and sulfides are of great significance for high energy density lithium-ion batteries(LIBs),but the huge volume expansion and inferior electronic conductivity upon cycling critically constrain their further ***,from a new perspective,a highly conductive and stable 3D flexible composite current collector is rationally designed by facilely electrodepositing metallic Ni thin layer onto the carbon cloth(CC/Ni),which endows the supported active materials with exceptional electronic conductivity and structural *** addition,the homogeneously distributed metallic Ni protrusions external CC can strongly bond with the active components,ensuring the structural integrity of electrodes upon *** importantly,the 3D network structure with large specific surface area provides abundant space to alleviate the volume expansion and more active sites for electrochemical ***,taking Ni_(3)S_(2)nanosheet(Ni_(3)S_(2)NS)anode as an example,the prepared Ni_(3)S_(2)NS@CC/Ni electrode shows a high specific capacity of 2.32 mAh/cm^(2)at 1mA/cm^(2)and high capacity retention of 1.68 mAh/cm^(2)at a high rate of 8mA/cm^(2).This study provides a universal approach to obtain highly conductive and stable 3D flexible current collectors towards high performance metal-ion batteries beyond LIBs.
Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP speci...
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Compressive strengths and elastic moduli of Carbon Fiber Reinforced Polymer(CFRP)composites can be noticeably improved by multiple ultra-thin interlays with non-woven Aramid Pulp(AP)micro/nano-fibers.10-ply CFRP specimens with 0,2,4,6,8 g/m^(2)AP were tested under uniaxial *** flexible AP fibers,filling the resin-rich regions and further constructing the fiber bridging at the ply interfaces,can effectively suppress delamination growth and lead to very good improvements both in the compressive strength and the elastic *** CFRP specimen with an optimum interlay thickness has a distinct shear failure mode instead of the typical delamination cracking along the direction of continuous carbon *** Strengths After Impacts(CAI)of 12.35 J were also measured,up to 90%improvement in CAI has been *** is concluded those ultra-thin interlays of non-woven AP micro/nano-fibers are beneficial to design and manufacture“high strength”CFRP composites.
Single wall carbon nanotube(SWCNT)/Si heterojunction photodetectors have the advantages of high photoresponse ability and simple structure,however,their detection wavelength range are usually lower than 1100 nm,which ...
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Single wall carbon nanotube(SWCNT)/Si heterojunction photodetectors have the advantages of high photoresponse ability and simple structure,however,their detection wavelength range are usually lower than 1100 nm,which limits their application in the infrared *** report a SWCNT/Cu/Si photodetector with both a high photoresponse and a detection range up to the infrared band by depositing a Cu nanoparticles(NPs)layer between a SWCNT film and a n-Si *** was found that the Cu NPs produce strong surface plasmon resonance(SPR)under laser irradiation,which breaks through the limitation of Si band gap and greatly improves the photoresponse of the SWCNT/Cu/Si photodetector in the near infrared *** responsivity(R)of the photodetector in the wavelength range of 1850–1200 nm reached 2.2–14.15 mA/W,which is the highest value in the reported plasmon enhanced n-Si based photodetectors,and about 20,000 times higher than that of a SWCNT/Si *** R value for 1550 nm wavelength used in optical communications reached~8.2 mA/W,which is 64%higher than the previously reported values of commonly used *** attribute the significant increase to the strong SPR and low Schottky barrier of Cu with n-Si,which facilitates the generation and transfer of the carriers.
A systematic experimental study was conducted on the similarities and differences in the reactions between commonly used rare earth elements(REEs)and frequently used refractories in the steelmaking *** results indicat...
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A systematic experimental study was conducted on the similarities and differences in the reactions between commonly used rare earth elements(REEs)and frequently used refractories in the steelmaking *** results indicate that the reaction behaviors of La,Ce,and Y with MgO,Al_(2)O_(3),and MgO·Al_(2)O_(3) crucibles differed *** consumption rates of La,Ce,and Y in the molten steel were in descending order of La>Ce>Y for smelting with all three kinds of *** the REEs reacted with the crucible,the contents of Mg and Al showed a trend of first increasing and then *** laboratory-scale smelting conditions,the reactions related to REEs were dominated by steel-crucible reactions,and the contact area between the unit mass of molten steel and refractory materials mainly determined the consumption rates of ***-and Ce-crucible reactions generated loose and porous reaction interfaces;however,Y-crucible reactions generated a dense Y_(2)O_(3) layer,dramatically suppressing the consumption rate of *** calculation indicated that the reactions between rare earth and different refractory materials were first-order *** crucible materials significantly affected the product type and morphology of the steel-crucible reaction interfaces,thereby influencing the consumption rate of *** reactions between REEs and refractories must be seriously considered,especially for small-scale smelting.
Enhanced piezoelectric response was usually achieved in(Bi_(0.5) Na_(0.5))TiO_(3)(BNT)-based ceramics with sacrifice of depolarization temperature T_(d),seriously limiting their usage range in electromechanical *** th...
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Enhanced piezoelectric response was usually achieved in(Bi_(0.5) Na_(0.5))TiO_(3)(BNT)-based ceramics with sacrifice of depolarization temperature T_(d),seriously limiting their usage range in electromechanical *** this work,we propose to explore piezoelectric anisotropy and domain engineering in compositionµstructure-controlled textured ceramics to resolve this issue.[001]c-textured 0.94(Bi_(0.5) Na_(0.5))TiO_(3)–0.06BaTiO_(3)(0.94BNT-0.06BT)ceramics with Lotgering factor F_(001)-91% were fabricated through homoepitaxial templated grain growth(TGG)via using 0.94BNT-0.06BT microplatelet *** textured samples exhibited more ordered domains with facilitated domain switching behavior,being consistent with saturated high polarization achieved at lower electric *** F_(001) to above 60%enables rapid enhancement of piezoelectric ***,compared to non-textured counterpart,the maximally textured ceramics exhibited-236%enhanced piezoelectric coefficient(d_(33)-302 pC/N)and-280% enhanced piezoelectric voltage coefficient(g_(33)-49.8×10^(−3)Vm/N),together with slightly increased depolarization temperature(T_(d)-106℃).Moreover,those values are approaching or even higher than the single-crystal *** work not only provides important guidelines for design and synthesis of novel textured ceramics with improved comprehensive electrical properties,but also can expand application fields of BNT-based ceramics.
Manipulating the motion of water droplets on surfaces, which is crucial for various applications, such as microfluidics and heat transfer, presents considerable challenges, primarily due to the significant influence o...
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