MXene nanomaterials are one of the most promising electrode material candidates for supercapacitors owing to their high conductivity,abundant surface functional groups and large surface ***,electrodes based on MXene m...
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MXene nanomaterials are one of the most promising electrode material candidates for supercapacitors owing to their high conductivity,abundant surface functional groups and large surface ***,electrodes based on MXene may result in low ion-accessible surface area and blocked ion transport pathways because of the self-restacking of MXene *** is essential to suppress the self-res tacking of nanosheets and increase the electrochemical active sites in order to optimize the *** this work,bidirectionally aligned MXene hybrid aerogel(A-MHA)assembled with MXene nanosheets and microgels is prepared using a facile bidirectional freeze casting and freeze-drying *** bidirectionally aligned structure together with the three-dimensional structured microgels in the A-MHAs,can improve the ionaccessible surface area and provide more barrier-free channels by exposing more active sites and ensuring electrolyte transport *** A-MHA with MXene microgels content of 40 wt%exhibits a high specific capacitance of 760 F·g^(-1)at 1 A·g^(-1)and a remarkable cyclic performance of 97%after 10,000 cycles at100 mV·s^(-1)in 1 mol·L^(-1)H_(2)SO_(4)electrolyte.A-MHAs show remarkable electrochemical properties and are of potential application in energy storage.
Hot spinning can make the material withstand shear stress, so that the shape of the material has a great change,which is one of the main processing methods of nickel-based alloy plate members. Inconel 625 alloy, which...
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Hot spinning can make the material withstand shear stress, so that the shape of the material has a great change,which is one of the main processing methods of nickel-based alloy plate members. Inconel 625 alloy, which has excellent high temperature mechanical properties and can be used as the main candidate material for aerospace applications, needs further study on its hot spinning deformation behavior and deformation mechanism. In this paper, the effect of feed rate on the microstructure evolution of Inconel 625 superalloy was studied by the electron backscattered diffraction technology. The microstructure with necklace-like structures composed of dynamic recrystallization(DRX) grains was observed after hot spinning. It was found that at the low feed rate, the promotion of DRX degree and grain refinement happened, where the grain size reached the trough of 10.99 μm under a feed rate of 300 mm/min. However, with the further feed rate rising, the degree of DRX was suppressed to a certain extent and grain size increased to 14.26 μm. On balance, the feed rate of 300 mm/min was the most efficient condition for grain refinement. Besides, it was revealed that both discontinuous dynamic recrystallization(DDRX) and continuous dynamic recrystallization(CDRX) occurred during hot spinning. DDRX includes the initial grain boundary nucleation by bulging and the annealing twin boundary assisted nucleation, while the CDRX mechanism is related to the continuous subgrain rotation within the deformed grain. DDRX is the main DRX mechanism.
On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling f...
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On the interface of the Cu-Al composite plate from horizontal continuous casting,the eutectic microstructure layer thickness ac-counts for more than 90%of the total interface thickness,and the deformation in rolling forming plays an important role in the quality of the composite *** eutectic microstructure material on the interface of the Cu-Al composite plate was prepared by changing the cooling rate of ingot solidification and the deformation in hot compression was *** results show that when the deformation temperature is over 300℃,the softening effect of dynamic recrystallization ofα-Al is greater than the hardening effect,and uniform plastic deformation of eutectic microstructure is *** constitutive equation of flow stress in the eutectic microstructure layer was established by Arrhenius hy-perbolic-sine mathematics model,providing a reliable theoretical basis for the deformation of the Cu-Al composite plate.
Reduced graphene oxide(rGO)enhanced B_(4)C ceramics was prepared by SPS sintering,the enhancement effect of rGO on the microstructure and mechanical properties of composites was studied through experiments and numeric...
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Reduced graphene oxide(rGO)enhanced B_(4)C ceramics was prepared by SPS sintering,the enhancement effect of rGO on the microstructure and mechanical properties of composites was studied through experiments and numerical *** results show that the composite with 2wt%rGO has the best comprehensive mechanical *** with pure boron carbide,vickers hardness and bending strength are increased by 4.8%and 21.96%,*** fracture toughness is improved by 25.71%.The microstructure observation shows that the improvement of mechanical properties is mainly attributed to the pullout and bridge mechanism of rGO and the crack *** on the cohesive force finite element method,the dynamic crack growth process of composites was *** energy dissipation of B_(4)C/rGO multiphase ceramics during crack propagation was calculated and compared with that of pure boron carbide *** results show that the fracture energy dissipation can be effectively increased by adding graphene.
The thermal reduction of graphene oxide(GO)was performed by a tube furnace at different temperatures,and its structure evolution was investigated in *** results showed that the oxygen-containing functional groups on t...
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The thermal reduction of graphene oxide(GO)was performed by a tube furnace at different temperatures,and its structure evolution was investigated in *** results showed that the oxygen-containing functional groups on the carbon plane surface of GO gradually decomposed as the temperature increase,and the reduced graphene oxide(rGO)powder was obtained at 800℃.Then,rGO powder was sintered under 30 MPa at 1800℃using spark plasma sintering(SPS)and hot-pressing(HP)to evaluate its structural stability at high *** defect densities of rGO were reduced after high-temperature *** edge flatness and sp^(2) hybrid carbon plane structure were reconstructed *** results demonstrate that the lamellar structure of rGO maintains the structural integrity during high-temperature sintering without obvious deterioration,which provides experimental and theoretical supports for GO reinforced ceramics.
To address the relatively mediocre mechanical properties of single-phase multi-component carbide ceramics,a phase transition from a single phase to multiple phases was proposed to achieve superior mechanical propertie...
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To address the relatively mediocre mechanical properties of single-phase multi-component carbide ceramics,a phase transition from a single phase to multiple phases was proposed to achieve superior mechanical properties.A series of(TiZrV_(x)Nb)C_(0.8) ceramics with different V contents were fabricated by spark plasma sintering(SPS).The influence of the V content on the phase composition,microstructural evolution,and mechanical properties was investigated in *** transition behavior from a single phase to multiple phases is discovered and *** formation of the Zr-rich phase and Zr-poor phase can be attributed to the increase in lattice distortion and mixed enthalpy caused by the addition of V.A nanometer lamellar structure with a semi-coherent interface obtained via in situ decomposition is reported for the first time in multi-component carbide *** semi-coherent interfaces with high dislocation density and strain concentration effectively improve the mechanical properties,grain refinement,and multi-phase *** optimal comprehensive mechanical properties of the Vickers hardness(26.3 GPa),flexural strength(369 MPa),and fracture toughness(3.1 MPa·m^(1/2))were achieved for the sample with 20 mol%V.
Similar to other metallic materials,duplex stainless steel dramatically loses its advantage of high ductility as they are ***,we produce a gradient nanograined dual-phase structure in the 2101 duplex stainless steel,t...
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Similar to other metallic materials,duplex stainless steel dramatically loses its advantage of high ductility as they are ***,we produce a gradient nanograined dual-phase structure in the 2101 duplex stainless steel,thus facilitating a superior strength-ductility synergy:a yield strength of 1009.5 MPa being two times higher than that of the as-received sample,a total elongation of 23.4%and a uniform elongation of 5.9%.This novel structure is produced through a processing route of ultrasonic severe surface rolling and annealing,which realizes a superposition of gradient nanostructure and lamellar dual-phase structure with austenite and *** the tension deformation of gradi-ent nanograined dual-phase structured duplex stainless steel,a significant accumulation of geometrically necessary dislocations *** dislocations are formed to accommodate the deformation incompat-ibility caused by the layer-by-layer difference in strength and hardness of individual phase domains,as well as the inherent difference in properties between the austenite and ferrite *** results in a stronger hetero-deformation induced strengthening and hardening significantly contributing to superior mechanical *** study provides a new avenue to develop advanced steels with high strength and ductility.
In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving *** them,acrylamide(AM)and 3-acrylamidopheny...
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In this study,the hydrogel network was reinforced by covalent-like hydrogen bonding,and the strong binding ability of boron-nitrogen coordination served as the main driving *** them,acrylamide(AM)and 3-acrylamidophenylboronic acid(AAPBA)were the main body,and the numerous hydroxyl groups in the trehalose(Treh)molecule and other polymer groups formed strong hydrogen bonding interactions to improve the mechanical properties of the PAM/PAAPBA/Treh(PAAT)hydrogel and ensured the simplicity of the synthesis *** hydrogel possessed high strain at break(1239%),stress(64.7 kPa),low hysteresis(100%to 500%strain,corresponding to dissipation energy from 1.37 to 7.80 kJ/m^(3)),and outstanding cycling stability(retained more than 90%of maximum stress after 200 ten-sile cycles).By integrating carbon nanotubes(CNTs)into PAAT hydrogel(PAATC),the PAATC hydrogel with excellent strain response performance was successfully *** PAATC conductive hydro-gel exhibited high sensitivity(gauge factor(GF)=10.58 and sensitivity(S)=0.304 kPa^(-1)),wide strain response range(0.5%-1000%),fast response time(450 ms),and short recovery time(350 ms),excellent fatigue resistance,and strain response ***,the PAATC-based triboelectric nanogener-ator(TENG)displayed outstanding energy harvesting performance,which shows its potential for appli-cation in self-powered electronic devices.
Magnesium and its alloys have attracting rising attention as one of biodegradable metallic ***,the rapid corrosion and severe localized corrosion still hinder their extensive applications in *** this study,micro-alloy...
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Magnesium and its alloys have attracting rising attention as one of biodegradable metallic ***,the rapid corrosion and severe localized corrosion still hinder their extensive applications in *** this study,micro-alloying of Ca(≤0.1 wt%)into Mg0.5Zn0.2Ge alloy developed in our previous work was explored to further enhance the corrosion resistance and alleviate the localized corrosion of the *** results reveal that the addition of Ca leads to the transformation of the cathodic Mg_(2)Ge phase in Mg0.5Zn0.2Ca alloy into anodic MgCaGe phase in Ca-containing alloys,thereby changing the galvanic couples in alloys during *** preferential dissolution of MgCaGe phase promotes the participation of Ca and Ge into the formation of corrosion products,resulting in the enrichment of Ca and Ge in the outmost of corrosion product layer,which stabilizes and passivates the corrosion product layer on Mg alloy ***,the enrichment of Zn at the corrosion interface seems to further hinder the corrosion of Mg *** of these factors confer a slower and more uniform corrosion on Mg0.5Zn0.2GexCa(x<0.1 wt%)alloy,which provides favorable candidates for the further processing to gain suitable biodegradable Mg alloys.
Developing metal-organic framework(MOF)materials with the moisture-resistant feature is highly desirable for CO_(2)capture from highly humid flue *** this work,a new core-shell MOF@MOF composite using Mg-MOF-74 with h...
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Developing metal-organic framework(MOF)materials with the moisture-resistant feature is highly desirable for CO_(2)capture from highly humid flue *** this work,a new core-shell MOF@MOF composite using Mg-MOF-74 with high CO_(2)capture capacity as a functional core and hydrophobic zeolitic imidazolate framework-8(ZIF-8)as a protective shell is fabricated by the epitaxial growth *** results show that the CO_(2)adsorption performance of the core-shell structured Mg-MOF-74@ZIF-8 composites from water-containing flue gas is enhanced along with their improved *** dynamic breakthrough results show that the Mg-MOF-74@ZIF-8 with three assembled layers(Mg-MOF-74@ZIF-8-3)can capture 3.56 mmol-g^(-1)CO_(2)from wet CO_(2)/N_(2)(VCO_(2):V_(N_(2))=15:85)mixtures,which outperforms Mg-MOF-74(0.37 mmol·g^(-1))and most of the reported physisorbents.
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