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Rare Metals 2024年第4期43卷 1786-1792页

作者： Yuan-Feng Xie Xing-Cheng Xie Zhong-Wu Li Rui-Jun Cao Zhong-Kun Lin Qing Li Chen-Guang Lin powder metallurgy and special Materials Research Department General Research Institute for Nonferrous MetalsBeijing100088China

The effects of cryogenic treatment(CT)and tempering-cryogenic treatment(TCT)on the microstructure and properties of coarse-grained WC-10Co cemented carbides with different carbon contents were *** binder phase,WC mean grain sizes,W solubility in the binder,relative magnetic s aturation,densities,hardness,wear resistance and second phase precipitation of cemented carbides with different heat treatments were *** results show that there are significant changes of microstructure and properties in the samples with CT and TCT,especially due to the precipitation of metastable nanoparticles W_(x)Co_(y)C_(z) in the binder during the heat treatments of CT and *** the simultaneous combination of microstructure and nanoparticle-reinforced binder,a dramatically improved combination of hardness and wear resistance of the samples after TCT has been achieved.

关键词： Cryogenic treatment Tempering Coarsegrained cemented carbide Carbon content Nanoparticlereinforced binder

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Single-source-precursor synthesis and air-plasma ablation behavior of(Ti,Zr,Hf)C/SiC ceramic nanocomposites at 2200℃

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Journal of Advanced ceramics 2024年第7期13卷 1043-1059页

作者： Li Lu Qingbo Wen Jinrun Hu Tianxing Jiang Xiangchao Ren Yalei Wang Yi Zeng Xiang Xiong State Key laboratory of powder metallurgy Central South UniversityChangsha 410083China

Dense monolithic(Ti,Zr,Hf)C/SiC ceramic nanocomposites with four different molar ratios of metallic elements in the(Ti,Zr,Hf)C phase(i.e.,Ti:Zr:Hf=1:1:1,2:3:5,2:3:3,and 1:2:1)were prepared upon pyrolysis of novel(Ti,Zr,Hf)-containing single-source precursors(SSPs),followed by spark plasma sintering(SPS).A thorough characterization was conducted to elucidate the synthesis of the SSPs,polymer-to-ceramic transformation,chemical/phase compositions,and microstructure of the SiTiZrHfC-based *** results revealed the feasibility of synthesizing nanocomposites with high(Ti,Zr,Hf)C contents using the SSP *** nanocomposites were characterized by a unique microstructure with in situ generated(Ti,Zr,Hf)C@C core-shell nanoparticles homogeneously mixed withβ-*** ablation behavior of the nanocomposites was evaluated on an air-plasma device for 60 ***,the nanocomposites exhibited excellent ablation resistance,and the lowest linear ablation rate reached−0.58μm/s at 2200°***,the ablation resistance can be dramatically improved by precisely tailoring the atomic ratios of metal elements within the(Ti,Zr,Hf)C phase via the molecular design of the *** formation of a multiple-oxide layer with both a high-meltingpoint phase((Ti,Zr,Hf)O_(2))and low-melting-point phases((Zr,Hf)TiO_(4))and glassy SiO_(2),as well as their structure,played a critical role in the enhanced ablation *** uniform distribution of the high-melting-point(Ti,Zr,Hf)O_(2)nano/microparticles throughout the glassy SiO_(2)matrix significantly enhanced the viscosity and stability of the oxide layer by the pinning effect,offering superior protection against the ingress of oxygen atoms and excellent resistance to mechanical erosion.

关键词： ultrahigh-temperature ceramics(UHTCs) multicomponent carbide nanocomposites ablation behavior multiple oxides

Mechanical Properties and Microstructure of the Shear Band Formed at Cryogenic Temperature in the NiCrFe Medium‑Entropy Alloy

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Acta Metallurgica Sinica(English Letters) 2024年第8期37卷 1377-1386页

作者： Ruoyu Liu Wenshu Li Xiayang Yu Lanyi Liu Bingfeng Wang School of Materials Science and Engineering Central South UniversityChangsha 410083China State Key laboratory of powder metallurgy Central South UniversityChangsha 410083China

There are nanotwins in the shear band formed in a moment(about 10^(−5)s)in some NiCrFe-based medium-entropy alloys(MEAs),and these shear bands can be recognized as a special kind of materials due to their high strength and good *** this study,the single shear band of the NiCrFe MEA was prepared at 77 K.A series of characterizations were carried out to analyze the microstructures in the shear *** strength of the shear band was investigated by the split Hopkinson pressure bar and in-situ *** micropillar in the shear band containing nanotwins exhibits excellent strengthplasticity *** compressive yield strength of the shear band measured by in-situ compression is 175%higher than that of the matrix,reaching 1405 MPa,with the fracture strain exceeding *** strengthening mechanism of the shear band was revealed by the combination of the experimental results and molecular dynamics *** synergistic effect of multiple strengthening mechanisms enhances the strength of the NiCrFe MEA containing nanotwins,in which the grain boundary strengthening of the ultrafine equiaxed grains and the dynamic Hall–Petch effect of the nanotwins *** addition,the good plasticity of the shear band is ascribed to the stress concentration reduction of the twin boundaries of nanotwins and the activation of multiple slip systems due to the randomly oriented *** findings provide theoretical guidance for the design of nanotwinned MEAs to realize excellent strength-plasticity synergy for structural materials.

关键词： Medium-entropy alloy Shear band Nanotwins Strengthening mechanism

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玻璃纤维板阵列增多层吸波复合结构

Journal of Central South University 2024年第2期31卷 384-398页

作者：麻晢乂培黎嘉乐姜超 powder metallurgy Research Institute Central South UniversityChangsha 410083China State Key laboratory of powder metallurgy Central South UniversityChangsha 410083China

本文将电路模拟吸波阵列与玻璃纤维介质板(FEPL)阵列结合,采用真空热压成型工艺制备了一种具有超宽带强吸波性能的多层复合结构。整个FEPL阵列复合结构的表面密度约为2.4 kg/m^(2),厚度约为10.0 mm。仿真和测量结果均表明,FEPL阵列可以... 详细信息

本文将电路模拟吸波阵列与玻璃纤维介质板(FEPL)阵列结合,采用真空热压成型工艺制备了一种具有超宽带强吸波性能的多层复合结构。整个FEPL阵列复合结构的表面密度约为2.4 kg/m^(2),厚度约为10.0 mm。仿真和测量结果均表明,FEPL阵列可以明显改善吸波结构的斜入射角的稳定性,提高电磁吸收率,拓宽吸收带宽。在斜入射角40°~60°范围内,FEPL阵列显著提高了吸波复合结构的吸收性能,同时将相对带宽(FBW)拓宽了约9.1%;此外,它还将复合吸波结构正入射角的平均反射系数从−14.4 dB降低到了−25.7 dB,降低了约11.3 dB。本文所提出的玻璃纤维板阵列增多层吸波复合结构性能优异,制备工艺简单,适合实际工程应用。

关键词：超宽带微波吸收复合材料玻璃纤维板阵列电路模拟吸波体

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Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides with enhanced oxidation resistance at 2500℃

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Journal of Advanced ceramics 2024年第3期13卷 332-344页

作者： Shiyan Chen Jinming Wang Zhaoke Chen Weilong Song Yi Zeng Xingchao Li Tongqi Li Xiang Xiong State Key laboratory of powder metallurgy Central South UniversityChangsha 410083China Aerospace Research Institute of Materials&Processing Technology China Academy of Launch Vehicle TechnologyBeijing 100076China

Enhancing oxidation resistance of multicomponent carbides above 2000℃is critical for their thermal protection *** this purpose,novel Nb-and Ta-doped(Hf,Zr,Ti)C multicomponent carbides were designed to improve their oxidation resistance at 2500℃.The results demonstrated that Nb and Ta doping reduced the oxidation rate constant by 16.67%and 25.17%,respectively,thereby significantly improving the oxidation resistance of(Hf,Zr,Ti)*** enhancement was attributed to the changes in oxycarbide composition and distribution within the oxide layer by adding Nb and *** to the different oxidation tendencies of the constituent elements,a distinctive structure was formed in which(Hf,Zr)O_(2)served as a skeleton,and various oxycarbides were dispersed throughout the oxide *** doped Nb and Ta were retained within oxycarbides,retarding the diffusion of oxygen into the *** importantly,the addition of Nb and Ta reduced the size of oxycarbides,decreasing both size and quantity of the pores in the oxide layer and facilitating the formation of a more effective oxygen barrier.

关键词： (Hf,Zr,Ti)C oxidation behaviour ultra-high-temperature oxidation Nb and Ta doping oxycarbides

Engineering S-scheme W_(18)O_(49)/ZnIn_(2)S_(4)heterojunction by Co_(x)P nanoclusters for enhanced charge transfer capability and solar hydrogen evolution

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Nano Research 2024年第9期17卷 8095-8103页

作者： Xiaojie Liu Erkang Liu Zixian Wang Wen Zhang Mingyu Dou Hua Yang Changhua An Dacheng Li Jianmin Dou Shandong Provincial Key laboratory of Chemical Energy Storage and Novel Cell Technology School of Chemistry and Chemical EngineeringLiaocheng UniversityLiaocheng 252059China Tianjin Key laboratory of Organic Solar Cell and Photochemical Conversion School of Chemistry and Chemical EngineeringTianjin Key Laboratory of Advanced Functional Porous MaterialsInstitute for New Energy Materials and Low-Carbon TechnologiesTianjin University of TechnologyTianjin 300384China Institute of powder metallurgy and Advanced ceramics School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China

Enhancement of the light-absorption response and utilization of the photogenerated carriers represent a robust strategy for the design of high-performance *** this work,grafting Co_(x)P nanoclusters onto S-scheme heterojunction of W18O49/ZnIn2S4(WO/ZIS-CoxP)with strong response to the ultraviolet-visible-near infrared ray(UV-vis-NIR)region has been achieved,which possesses efficient electron-transfer-channel,and boosts charge-separation and transport *** as-prepared WO/ZIS-Co_(x)P yields an impressive solar-driven hydrogen production rate of 45 mmol·g^(-1)·h^(-1).The increased photocatalytic performance is attributed to the synergistic effect of the composite catalyst:(1)The local surface plasmon resonance-induced“hot electron”injection of W_(18)O_(49)significantly increases the electron density;(2)the engineered S-scheme directional electron transfer promotes charge separation and enhances the reducing capability of photoexcited electrons;and(3)Co_(x)P as electron-trap site for accelerating surface proton reduction *** work provides a platform to impart nonprecious co-catalyst for engineering S-scheme heterojunction,serving a class of efficient solar-driven photocatalyst towards hydrogen production.

关键词： hydrogen cocatalyst photocatalysis S-scheme hot electron

Prediction of the thermal conductivity of Mg–Al–La alloys by CALPHAD method

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International Journal of Minerals,metallurgy and Materials 2024年第1期31卷 129-137页

作者： Hongxia Li Wenjun Xu Yufei Zhang Shenglan Yang Lijun Zhang Bin Liu Qun Luo Qian Li State Key laboratory of Advanced special Steels&Shanghai Key laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China State Key laboratory of powder metallurgy Central South UniversityChangsha 410083China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Key laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

Mg-Al alloys have excellent strength and ductility but relatively low thermal conductivity due to Al *** accurate prediction of thermal conductivity is a prerequisite for designing Mg-Al alloys with high thermal ***,databases for predicting temperature-and composition-dependent thermal conductivities must be *** this study,Mg-Al-La alloys with different contents of Al2La,Al3La,and Al11La3phases and solid solubility of Al in the α-Mg phase were *** influence of the second phase(s) and Al solid solubility on thermal conductivity was *** results revealed a second phase transformation from Al_(2)La to Al_(3)La and further to Al_(11)La_(3)with the increasing Al content at a constant La *** degree of the negative effect of the second phase(s) on thermal diffusivity followed the sequence of Al2La>Al3La>Al_(11)La_(3).Compared with the second phase,an increase in the solid solubility of Al in α-Mg remarkably reduced the thermal *** the basis of the experimental data,a database of the reciprocal thermal diffusivity of the Mg-Al-La system was established by calculation of the phase diagram (CALPHAD)*** a standard error of±1.2 W/(m·K),the predicted results were in good agreement with the experimental *** established database can be used to design Mg-Al alloys with high thermal conductivity and provide valuable guidance for expanding their application prospects.

关键词： magnesium alloy thermal conductivity thermodynamic calculations materials computation

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An ultrahigh energy storage efficiency and recoverable density in Bi_(0.5)Na_(0.5)TiO_(3)with the modification of Sr_(0.85)La_(0.1)TiO_(3)via viscous polymer process

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Journal of Materiomics 2024年第3期10卷 566-577页

作者： Fukang Chen Lishun Yang Haoran Feng Qin Li Xinyu Zeng Kun Yu Chunlin Song Yan Yan Li Jin Dou Zhang School of Materials and Energy Southwest UniversityChongqing400715China Electronic Materials Research laboratory Key Laboratory of the Ministry of EducationSchool of Electronic Science and EngineeringXi'an Jiaotong UniversityXi'an710049China State Key laboratory of powder metallurgy Central South UniversityChangsha410083China

Currently,the development of dielectric ceramic capacitors is restricted by the contradiction between high efficiency and high recoverable ***,a novel strategy was designed to achieve a su-perior balance between ***,introducing Sr_(0.85)La_(0.1)TiO_(3)can enhance the content of the weak polar phase(P4bm)to become the main component,which can optimize the relaxor behaviour and improve ***,the electric breakdown strength was effectively enhanced by grain refinement and viscous polymer ***,a high recoverable energy density of~5.3 J/cm^(3)and an excellent efficiency of~92.2%were attained in 0.9Bi_(0.5)Na_(0.5)TiO_(3)-0.1Na_(0.8)Sr_(0.1)NbO_(3)ceramic with the addition of 0.35Sr_(0.85)La_(0.1)TiO_(3)after viscous polymer *** piezoelectric force microscope had been applied to prove the high activity of the polar nanoregions and finite element analysis was adopted to explain the reasons for the enhancing electric breakdown *** addition,this ceramic exhibits good tem-perature and frequency stability,and a fast discharging rate of 0.11 ms,making it a potential candidate for the actual application.

关键词： Lead-free ceramics Energy storage BNT Landau-free energy

An ultrafast rechargeable hybrid potassium dual-ion capacitor based on carbon quantum dot@ultrathin carbon film cathode

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Rare Metals 2024年第10期43卷 5070-5081页

作者： Zhao-Meng Liu Da Wang Shang-Zhuo Li Qing-Song Lai Dong-Run Yang Lu-Kang Zhao Jian-Jia Mu Xuan-Chen Wang Xuan-Wen Gao Wen-Bin Luo Institute for Energy Electrochemistry and Urban Mines metallurgy School of MetallurgyNortheastern University Key laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai University

Ultrafast rechargeable hybrid potassium dualion capacitors （HPDICs） were designed by employing carbon quantum dot@ultrathin carbon film （CQD@CF） as the cathode *** designed CQD@CF is selfassembled by a simple catalytic graphitization route followed by an acid leaching *** special composite features a large adsorption interface,a remarkable anion hybrid storage capability and outstanding structure *** electrochemical performance of CQD@CF composite is fully tapped in a half-cell system at the operating voltage between 1.4 and 4.5 V,achieving an admirable specific discharge capacity of 128.5 mAh·g-1a 50 mA·g-1,an ultra-high capacity retention ratio of 97.97% after cycling 5000 times at 1000 mA·g-1and a 96.10%high capacity retention ratio after cycling 40,000 times at 5000 mA·g-1,***,with the support of ex situ TEM and XPS,the structural stability principle and anionic hybrid storage mechanism of CQD@CF electrode are investigated *** the full-cell system,HPDICs with the CQD@CF as cathode and nanographite powder as anode also present a 141.5 Wh·kg-1high energy density,a 5850 W·kg-1power density and a super-long cycle stability (90.2% capacity retention ratio after cycling 30,000 times at 5000 mA·g-1).

关键词： Anion hybrid storage mechanism Carbon quantum dots Potassium dual ion capacitor Ultrafast rechargeable Ultrathin carbon film

Effect of nano-graphite on mechanical properties and oxidation resistance of ZrB_(2)-SiC-graphite electrode ceramics

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Journal of Iron and Steel Research International 2024年第6期31卷 1502-1513页

作者： Bo-lin Yang Chang-liu Kuang Zheng-long Liu Chao Yu Cheng-ji Deng Jun Ding The State Key laboratory of Refractories and metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina

ZrB_(2)-based ceramic composites were prepared by spark plasma sintering using ZrB_(2) powder prepared by molten salt method as raw material and SiC and nano-graphite as *** effects of nano-graphite addition on the physical properties and oxidation resistance of ZrB_(2)-based ceramic samples were *** results show that the addition of an appropriate amount of nano-graphite can effectively improve the density of ZrB_(2)-based ceramic composites and improve the physical properties of the *** flexural strength of the ceramic sample with 8 vol.%nano-graphite reached 418.54 MPa,which was 53.14% higher than that of ZrB_(2)-SiC ceramic material(273.31 MPa),and its oxidation resistance was also significantly *** demonstrats that the addition of an appropriate amount of nano-graphite can effectively improve the physical properties and oxidation resistance of ZrB_(2)-SiC ceramic *** prolonging its service life in application and promoting the development of ZrB_(2)-based ceramic composites,it is of great significance for clean steel smelting.

关键词： ZrB_(2)-SiC-graphite electrode ceramic ZrB_(2)-based ceramic composite Nano-graphite Physical property Oxidation resistance