A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix *** edge-to-e...
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A novel melting infiltration by ultrasonic vibration was investigated and applied to fabricate Ti6Al4V(TC4)lattice structure-reinforced Mg-10Gd-2Y-1Zn-xZr(refer to VW92 hereafter,x=0,0.5 wt%)alloy matrix *** edge-to-edge matching model indicates that the well-matching and possible orientation relationships(ORs)between theα-Mg andα-Ti,[10-10]_(α-Mg)//[11-23]_(α-Ti) in(0002)_(α-Mg)//(10-10)_(α-Ti) possesses the smallest misfit of 0.4%(f_(r)),and thus theα-Mg grains can nucleate on the TC4 lattice *** reaction occurred in the TC4/VW92+0.5 wt%Zr composites,and the reaction product was confirmed to be Al_(2)Zr_(3),AlZr_(2) andα-Ti(Zr)particles formed by continuous solution of *** the interfacial products,the AlZr_(2) phase is a brittle phase with high-volume fraction,which is not conducive to the load *** generally speaking,theα-Ti(Zr)and theα-Mg tend to form a coherent interface,which is beneficial for improving the interfacial bonding strength of composites.
Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution *** report a CuO nanoparticles incorpor...
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Electrocatalytic nitrate reduction reaction (NO_(3)-RR) to ammonia under ambient conditions is expected to be a green process for ammonia synthesis and alleviate water pollution *** report a CuO nanoparticles incorporated on nitrogen-doped porous carbon (CuO@NC) catalyst for NO_(3)-*** of Cu(Ⅱ) is reduced to Cu(Ⅰ) during the NO_(3)-RR process to construct Cu(Ⅰ)-Cu(Ⅱ) pairs,confirmed by in situ X-ray photoelectron spectroscopy (XPS) and Raman *** functional theory (DFT) calculations indicated that the formation of Cu(Ⅰ) could provide a reaction path with smaller energy barrier for NO_(3)-RR,while Cu(Ⅱ) effectively suppressed the competition of hydrogen evolution reaction (HER).As a result,CuO@NC catalyst achieved a Faradaic efficiency of 84.2% at -0.49 V versus reversible hydrogen electrode (RHE),and a NH_(3)yield rate of 17.2 mg h^(-1)mg^(-1)*** -0.79 V ***,higher than the HaberBosch process (<3.4 g h^(-1)g^(-1)cat.).This work may open a new avenue for effective NO_(3)-RR by modulating oxidation states.
In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ***,by combining experiment and phase-field crystal simulation,we found th...
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In Ti-Al laminated composites,cracks nucleate preferentially at the Al_(3)Ti layer,but the inhibitory effect of Al_(3)Ti on crack extension is ***,by combining experiment and phase-field crystal simulation,we found that the micrometer Al_(3)Ti particles in the diffusion layer play the role of crack deflection and passivation,which is attributed to the lattice distortion induced by Al_(3)Ti consumes the energy of the crack in *** addition,it is found that the growth process of Al_(3)Ti is divided into two stages:nucleation stage and growth *** with the growth stage,the Al_(3)Ti grains in the nucleation stage are finer in the growth *** grains show better crack deflection and avoid stress concentration.
The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive ***,screening suitable coating agents to enhance the interfacial ef...
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The interfacial interaction between HMX molecules and coating materials is the key to the safety performance of explosives and has received extensive ***,screening suitable coating agents to enhance the interfacial effect to obtain high-energy and low-sensitivity explosives has long been a major *** this work,HMX-PEI/rGO/g-C_(3)N_(4)(HPrGC)composites were innovatively prepared by a multi-level coating strategy of two-dimensional graphite rGO and g-C_(3)N_(4).The g-C_(3)N_(4) used for desensitization has a richπ-conjugated system and shows outstanding ability in reducing friction *** hierarchical structure of HPrGC formed by electrostatic self-assembly andπ-πstacking can effectively dissipate energy accumulation under heat and mechanical stimulation through structural evolution,thus exhibiting a prominent synergistic desensitization effect on *** results show that rGO/gC_(3)N_(4) coating has no effect on the crystal structure and chemical structure of *** importantly,the perfect combination of g-C_(3)N_(4) and rGO endows HPrGC with enhanced thermal stability and ideal mechanical sensitivity(IS:21 J,FS:216 N).Obviously,the new fabrication of HPrGC enriches the variety of desensitizer materials and helps to deepen the understanding of the interaction between explosives and coatings.
Cleanliness control of advanced steels is of vital importance for quality control of the *** order to understand and control the inclusion removal during refining process in molten steel,its motion behaviors at the mu...
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Cleanliness control of advanced steels is of vital importance for quality control of the *** order to understand and control the inclusion removal during refining process in molten steel,its motion behaviors at the multiple steel/gas/slag interfaces have attracted the attention much of metallurgical *** recent development of the agglomeration of non-metallic inclusions at the steel/Ar and steel/slag interfaces has been summarized,and both the experimental as well as theoretical works have been *** terms of in situ observation of high-temperature interfacial phenomena in the molten steel,researchers utilized high-temperature confocal laser scanning microscopy to observe the movement of more types of inclusions at the interface,i.e.,the investigated inclusion is no longer limited to Al_(2)O_(3)-based inclusions but moves forward to rare earth oxides,MgO-based oxides,*** terms of theoretical models,especially the model of inclusions at the steel/slag interface,the recent development has overcome the limitations of the assumptions of Kralchevsky-Paunov model and verified the possible errors caused by the model assumptions by combining the water model and the physical *** but not least,the future work in this topic has been suggested,which could be in combination of thermal physical properties of steels and slag,as well as utilize the artificial intelligence-based methodology to implement a comprehensive inclusion motion behaviors during a comprehensive metallurgical process.
The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced ...
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The A_(2)B_(2)O_(7)-type rare earth zirconate compounds have been considered as promising candidates for thermal barrier coating(TBC) materials because of their low sintering rate,improved phase stability,and reduced thermal conductivity in contrast with the currently used yttria-partially stabilized zirconia (YSZ) in high operating temperature *** review summarizes the recent progress on rare earth zirconates for TBCs that insulate high-temperature gas from hot-section components in gas *** on the first principles,molecular dynamics,and new data-driven calculation approaches,doping and high-entropy strategies have now been adopted in advanced TBC materials *** this paper,the solid-state heat transfer mechanism of TBCs is explained from two aspects,including heat conduction over the full operating temperature range and thermal radiation at medium and high *** paper also provides new insights into design considerations of adaptive TBC materials,and the challenges and potential breakthroughs are further highlighted for extreme environmental *** for improving thermophysical performance are proposed in two approaches:defect engineering and material compositing.
In recent years, sodium-ion batteries(SIBs) have received renewed attention due to the continued rise in lithium prices. SIBs are promising to replace lithium-ion batteries under various application scenarios, such as...
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In recent years, sodium-ion batteries(SIBs) have received renewed attention due to the continued rise in lithium prices. SIBs are promising to replace lithium-ion batteries under various application scenarios, such as large-scale energy storage systems and low-speed electric vehicles. As the core of SIBs, electrode materials are the key factor demining the electrochemical performance. Key drawback, including cycle stability, air stability and energy density, are refraining the development of SIBs off-industrialization. For a systematic understanding on the development of SIBs, in this review, we summarized the progress of SIBs from the industrialization viewpoint,including the fabrication methods suitable for large scale production of electrode materials of SIBs, and the optimization strategies to improve electrochemical performance. Finally, we proposed promising directions for future development of electrode materials for SIBs toward industrialization.
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.
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.
Cr2AlC,a representative MAX phase,gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation ***,the lack of the phase formation mecha...
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Cr2AlC,a representative MAX phase,gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation ***,the lack of the phase formation mechanism has become the key bottleneck to the practical applications for Cr2AlC synthesis with high purity at low *** this work,we fabricated the amorphous Cr-Al-C coating by a hybrid magnetron sputtering/cathodic arc deposition technique,in which the in-situ heating transmission electron microscopy(TEM)was conducted in a temperature range of 25-650 ℃ to address the real-time phase transformation for Cr2AlC *** results demonstrated that increas-ing the temperature from 25 to 370 ℃ led to the structural transformation from amorphous Cr-Al-C to the crystalline Cr2Al ***,the high-purity Cr2AlC MAX phase was distinctly formed at 500 ℃,accompanied by the diminished amorphous *** the further increase of temperature to 650 ℃,the decomposition of Cr2AlC to Cr7C3 impurities was *** phase evolution was also evidenced by the Ab-initio molecular dynamics calculations,where the bond energy of Cr-Cr,Cr-Al,and Cr-C played the key role in the formed crystalline stability during the heating *** observa-tions not only provide fundamental insight into the phase formation mechanism for high-purity Cr2AlC coatings but also offer a promising strategy to manipulate the advanced MAX phase materials with high tolerance to high-temperature oxidation and heavy ion radiations.
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