查看更多>>摘要：Cavitation,corrosion,and fouling are critical factors that significantly impact the performance of power components in large cargo ships.To address these issues,a composite coating called epoxy-modified polyurea(PUE-FD)has been developed with reproducible self-healing properties.The incorporation of functionally reduced graphene oxide(FrGO)with multiple hydrogen bonds in the coating led to a notable increase of 5.6 MPa in the tensile strength of PUE-FD.This enhancement was accompanied by excellent resistance to cavitation,as evidenced by a mere 2.8 mg mass loss after 60 h of continuous cavitation.Fur-thermore,the inclusion of FrGO exhibited an exceptional barrier effect,providing PUE-FD with superior corrosion protection.The|Z|0.01 Hz value of PUE-FD was 9.01 × 109 Ω cm2 after 15 days of immersion in 3.5 wt％NaCl solution.Additionally,the synergistic effect of 2-octyl-4,5-dichloroisothiazolinone(DCOIT)and FrGO resulted in remarkable antifouling performance,with a bacterial removal rate exceeding 99.4％and a microalgae removal rate of up to nearly 100％for PUE-FD.PUE-FD also demonstrated remarkable photothermal self-healing ability,achieving a self-healing efficiency of 89％within just 60 s of near-infrared irradiation.Moreover,the presence of hydrogen bonds in FrGO contributes to the excellent ad-hesion properties of PUE-FD,resulting in adhesion strengths of more than 10 MPa on copper,stainless steel,and aluminum surfaces.This work presents new inspirations for the preparation of multifunctional coatings with anti-cavitation,anticorrosion,antifouling,and self-healing properties.
查看更多>>摘要：The swift advancement of electronics technology has led to a burgeoning interest in multifunctionaliz-ing electromagnetic wave(EMW)absorption materials as a prospective avenue for future development.However,the effective integration of diverse functions within a single material continues to present chal-lenges.This work successfully fabricated a three-dimensional(3D)porous Co6Mo6C2/Mo2C@NC frame-work with carbon microspheres through uncomplicated freeze-drying and high-temperature pyrolysis techniques.The resultant magnetic bimetallic carbide(Co6Mo6C2 and Mo2C)nanoparticles are uniformly and densely embedded within the carbon layer,facilitated jointly by a rigid template(molybdenum salt)and a flexible template(glucose),thus realizing an exceptional dual loss mechanism involving dielectric and magnetic components.The establishment of the 3D porous conductive network enhances EMW ab-sorption through multiple reflections and scattering mechanisms.Impressively,the Co6Mo6C2/Mo2C@NC framework attains remarkable EMW absorption characteristics with ultralightweight(0.1567 g cm-3),ul-trathin matching thickness(1.7 mm),and robust absorption(reflection loss RL value of-65.89 dB).Fur-thermore,it achieves a noteworthy effective absorption bandwidth(EAB,RL ≤-10 dB)spanning 6.4 GHz,ensuring complete absorption of 100％within the X band(8-12 GHz)at a matching thickness of 2 mm.In addition,the Co6Mo6C2/Mo2C@NC framework exhibits pronounced hydrophobicity and magnetic respon-siveness,bestowing upon it appealing attributes including self-cleaning,flame retardancy,and thermal insulation,on par with those observed in commercial products.The radar cross-sectional area(RSC)re-duction value of the Co6Mo6C2/Mo2C@NC framework can reach 35.2 dB m2 by RSC simulation,which can effectively lower the likelihood of detection by radar detectors for the target.This study presents a viable strategy for the advancement of novel lightweight and multifunctional materials that demonstrate exceptional performance in absorbing electromagnetic waves.
查看更多>>摘要：Tailoring high-density annealing twins in laser powder bed fusion(LPBF)-fabricated alloys based on their intrinsic residual stress requires high annealing temperatures and/or long-term annealing,result-ing in the abnormal growth of large recrystallized grains,which is detrimental to mechanical properties.This work proposes a new strategy for achieving a favorable strength-plasticity synergy of the LPBF-fabricated Inconel 718 superalloy by performing a deep cryogenic treatment(DCT)with the subsequent heat treatment(including annealing and double aging)to tailor fine grains with"high-density annealing twins+precipitates"architectures and compares the obtained material with an alloy subjected to a direct heat treatment without a prior DCT.The obtained results reveal that the additional internal stress gen-erated during DCT increases the stored energy and dislocation density,which provide a sufficient driving force for activating high-density annealing twin boundaries(63.2％)with fine grains(31.6 μm)within a short annealing time.The more homogeneous tailored microstructure with the"finer grains+high-density twins+precipitates"architectures decreases the mean free path of slipping dislocations,pro-moting intensive interactions with dislocations and inducing a strong strain hardening effect.The mul-tiple deformation modes of stacking faults coupled with Lomer-Cottrell locks,thin primary deformation twins,and secondary twins activated during tensile loading,sustaining a strong work hardening ability and delaying the plastic instability,which exhibits a high strength(yield strength of 1088 MPa and tensile strength of 1369 MPa)and excellent plasticity(elongation of 30％).This work not only describes a fea-sible method for simultaneously enhancing the strength and plasticity in additively manufactured(AM)alloys but also provides new insights into increasing the fraction of twins at a small grain size to improve the grain boundary-related properties without destroying the AM alloy shape.
查看更多>>摘要：Given the unique nanolaminate structure,the MAX phase ceramics which are composed of alternatively stacked two-dimensional(2D)metal(M)carbides(X)and main group(A)atomic layers have shown promising properties at elevated temperatures.Recently,an excellent self-lubricating performance of a high-entropy(HE)(TiVCrMo)3AlC2 MAX is demonstrated at 800 ℃ in the air.However,the formation mechanism of a self-lubricative tribofilm is still waiting for clarified.In this work,the HE(TiVCrMohAlC2 MAX is synthesized and its oxidation behaviors are systematically evaluated at 800 ℃ in the air.A two-stage parabolic oxidation behavior is detected,which can be mainly ascribed to the volatilization of MoO3 species coupled with the thickening of the compound oxide scale.Meanwhile,the HE com-position results in chemically complex phases including Rutile and vacancy-ordered TiO species in the oxide scale,which contribute to a higher ion diffusion rate for mass transportation.Consequently,the continued volatilization of MoO3 is beneficial for the enhanced lubricity and anti-wear performance of the(TiVCrMo)3AlC2 MAX at 800 ℃.
查看更多>>摘要：Designing low-cost and high-efficiency bifunctional electrocatalysts is one of the challenges in the clean production of hydrogen energy in electrochemical water splitting.Transition metal selenides(TMSes)have been widely studied because of their low price,intrinsic metal properties,and high catalytic ac-tivity.In addition,the synergistic effect between bimetallic selenides exhibits better performance than monometallic selenides in the electrocatalytic process.Herein,we synthesized V-doped NiSe2 nanowire arrays on pretreated nickel foam by a convenient two-step hydrothermal synthesis method.In the al-kaline electrolyte,V-NiSe2/NF exhibited excellent OER catalytic activity(293.6 mV@50 mA cm-2).In ad-dition,the introduction of heteroatom V induces stronger electronic interactions between the structural atoms of the catalyst,altering the electronic structure and causing V-NiSe2/NF to demonstrate excellent OER performance.In the long-term OER test,V-NiSe2/NF was converted into NiOOH and SeOx2-,which may be the"real"active species during catalytic reactions,and we also successfully captured the for-mation of intermediate NiOOH and selenite as active centers in the OER process through in-situ Raman.The theoretical calculation shows that the electron transfer modulates the electron structure,changes the adsorption-desorption energy of the reaction intermediates,reduces the potential barrier of the rate-limiting step,and improves the OER activity.The V doping engineering strategy and the unique nanowire array structure make TMSes exhibit excellent OER performance.This study provides a new idea for the design of TMSe catalysts with excellent electrocatalytic performance.
查看更多>>摘要：The twinning-induced plasticity(TWIP)effect has been widely utilized in austenite steels,β-Ti alloys,and recently developed face-centered-cubic(FCC)high-entropy alloys(HEAs)to simultaneously enhance the tensile strength and ductility.In this study,for the first time,the TWIP effect through hierarchical{332<113>mechanical twinning has been successfully engineered into the TiZrHfNb refractory HEAs by decreasing temperature and tailoring the content of Nb to destabilize the BCC phase.At cryogenic tem-perature,the comprehensive hierarchical {332}<113>mechanical twins are activated in TiZrHfNb0.5 alloy from micro-to nanoscale and progressively segment the BCC grains into nano-scale islands during de-formation,ensuring sustainable strain hardening capability and eventually achieving a substantial 35％uniform tensile elongation.In addition,at 77 K,the tensile strength and uniform elongation of TiZrHfNbx alloys can further be adjusted by a moderate increase of Nb.The results above shed new light on the de-velopment of high-performance refractory HEAs with a high and adjustable strength and ductility com-bination down to the cryogenic temperature.
查看更多>>摘要：In this work,a high-strength crack-free TiN/Al-Mn-Mg-Sc-Zr composite was fabricated by laser powder bed fusion(L-PBF).A large amount of uniformly distributed L12-Al3(Ti,Sc,Zr)nanoparticles were formed during the L-PBF process due to the partial melting and decomposition of TiN nanoparticles under a high temperature.These L12-Al3(Ti,Sc,Zr)nanoparticles exhibited a highly coherent lattice relationship with the Al matrix.All the prepared TiN/Al-Mn-Mg-Sc-Zr composite samples exhibit ultrafine grain mi-crostructure.In addition,the as-built composite containing 1.5 wt％TiN shows an excellent tensile prop-erty with a yield strength of over 580 MPa and an elongation of over 8％,which were much higher than those of wrought 7xxx alloys.The effects of various strengthening mechanisms were quantitatively estimated and the high strength of the alloy was mainly attributed to the refined microstructure,solid solution strengthening,and precipitation strengthening contributed by L12-Al3(Ti,Sc,Zr)nanoparticles.
查看更多>>摘要：Compared with cold rolling,warm rolling can significantly reduce or completely eliminate microstruc-ture damage to regulate the microstructure of the material,which is an effective method to improve the mechanical properties of the material.However,the effect of warm rolling on refractory complex concen-trated alloys(RCCAs)has rarely been reported.This research examines how warm rolling influences the microstructure,texture,and mechanical properties of the Zr45Ti15Nb30Ta10 RCCA.The RCCA was warm-rolled to a 75％reduction in thickness at 650 ℃(two-phase zone)and then annealed at 1000 ℃ for 1 h.To highlight the advantages of warm rolling,a comparison was conducted with similarly deformed and annealed cold-rolled RCCA.The warm-rolled RCCA exhibits a layered heterogeneous structure and induces the precipitation of the(Nb,Ta)-enriched bcc2 phase.The deformation texture of warm-rolled RCCA is weaker than that of cold-rolled RCCA,which is attributed to localized deformation inhomogene-ity.After annealing,warm rolling resulted in a remarkable increase in the yield strength of the RCCA,i.e.,from 861 MPa to 1071 MPa;meanwhile,moreover,the tensile plasticity was almost identical.Warm rolling leads to a change in plastic deformation of the RCCA from dislocation cross-slip to one dominated by the interaction of dislocations with subgrain boundaries as well as the bcc2 phase.The back tress gen-erated by the heterogeneous structure induced by warm rolling is also effective in increasing the yield strength of the RCCA.The remarkably layered heterogeneous structure,subgrain boundaries and textures result in warm-rolled RCCA with optimal strength-ductility combination.Our results provide an effective processing approach for tailoring the microstructure and mechanical properties of RCCAs.
查看更多>>摘要：UV-visible broadband light harvesting ability is critical for photodetectors,and all inorganic perovskite CsPbBr3 is regarded as a promising candidate as the response active material.Herein,a saturated-solution crystallization method is employed to synthesize CsPbBr3 single crystal.Temperature-dependent photo-luminescence spectra with one-photon and two-photon excitation are systematically investigated,deter-mining a large exciton binding energy of 39.8 meV.This allows the stable excitonic emission of CsPbBr3 single crystal at room temperature.Subsequently,an asymmetric structure CsPbBr3 photodetector is fab-ricated by using InGa alloy as the Ohmic electrode and Au as the Schottky electrode.At-8 V,the device exhibits a prominent response to the irradiation from UV to green band with a maximum responsiv-ity of 2.56 A/W,an external quantum efficiency of 580％,and a detectivity of 1.24 × 1013 Hz1/2 W-1.In addition,the CsPbBr3 photodetector also presents rapid response speeds at both reverse and forward bias voltages and self-powered characteristics owing to the Schottky depletion layer underneath the Au electrode.The demonstration of asymmetric metal-semiconductor-metal(MSM)structure photodetector presents a promising pathway toward next-generation CsPbBr3 optoelectronic devices.
查看更多>>摘要：Seawater electrolysis is one most promising development directions for future hydrogen energy.How-ever,big challenges of active site poisoning,chloride oxidation(ClOR),and chloride corrosion on anode electrocatalysts,seriously impede seawater electrolysis development.Therefore,developing efficient an-odic oxygen evolution reaction(OER)electrocatalysts is an urgent task for seawater electrolysis.The ad-vanced strategies of improving OER kinetics,lowering ClOR kinetics,strengthening corrosion resistance,and recombining multifunction are summarized and analyzed to help researchers quickly grasp the re-cent progress on seawater oxidation.The outlooks for future research are put forward.The future research directions are proposed as internal and external cultivation,giving full play to the physicochemical prop-erties of electrocatalysts,making sense of structure evolution and OER mechanism,and elucidating the electrical double layer of electrocatalysts.A lot of room for scalable application of seawater electrolysis calls for persistent effort and devotion of related researchers to boost seawater electrolysis development and universal hydrogen energy application.
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