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Microstructure and mechanical properties stability of pre-hardening treatment in Al-Cu alloys for pre-hardening forming process

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International Journal of Minerals,Metallurgy and materials 2024年第3期31卷 539-551页

作者： Liping Tang Pengfei Wei Zhili Hu Qiu Pang Hubei Longzhong laboratory Xiangyang 441000China Hubei Key Laboratory of Advanced Technology for Automotive Components School of Automotive EngineeringWuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center for Green&Precision Material Forming Wuhan University of TechnologyWuhan 430070China Key Laboratory of Metallurgical Equipment and Control Technology of Ministry of Education School of Machinery and AutomationWuhan University of Science and TechnologyWuhan 430081China

The stability of the microstructure and mechanical properties of the pre-hardened sheets during the pre-hardening forming(PHF)process directly determines the quality of the formed *** microstructure stability of the pre-hardened sheets was in-vestigated by differential scanning calorimetry(DSC),transmission electron microscopy(TEM),and small angle X-ray scattering(SAXS),while the mechanical properties and formability were analyzed through uniaxial tensile tests and formability *** results in-dicate that the mechanical properties of the pre-hardened alloys exhibited negligible changes after experiencing 1-month natural aging(NA).The deviations of ultimate tensile strength(UTS),yield strength(YS),and sheet formability(Erichsen value)are all less than 2%.Also,after different NA time(from 48 h to 1 month)is applied to alloys before pre-hardening treatment,the pre-hardened alloys possess stable microstructure and mechanical properties as ***,with the extension of NA time before pre-hardening treatment from 48 h to 1 month,the contribution of NA to the pre-hardening treatment is *** a yield strength increment of 20 MPa is achieved,with no loss in *** limited enhancement is mainly attributed to the fact that only a limited number of clusters are transformed into Guinier-Preston(GP)zones at the early stage of pre-hardening treatment,and the formation ofθ''phase inhibits the nucleation and growth of GP zones as the precipitated phase evolves.

关键词： Al-Cu alloy pre-hardened alloy natural aging mechanical properties microstructure

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Omnidirectionally impedance-matched phononic crystals for full-parameter transformation acoustics

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Science China(Physics,Mechanics & Astronomy) 2025年第5期68卷 16-21页

作者： Chenkai Liu Jie Luo Xiaozhou Liu Yun Lai MOE Key Laboratory of Modern Acoustics National Laboratory of Solid State MicrostructuresSchool of Physicsand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjing 210093China School of Physical Science and Technology&Jiangsu Key Laboratory of Frontier Material Physics and Devices Soochow UniversitySuzhou 215006China State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

In this work,we present an approach to realize full-parameter transformation acoustic media utilizing phononic crystals instead of metamaterials,which has the exceptional advantages of omnidirectional impedance matching and configurable dispersion *** employing a sandwich structure,we demonstrate phononic crystals that exhibit tunable shifted elliptical equal frequency contours and nearly omnidirectional impedance matching *** typical acoustic devices,including a beam shifter and an illusionary scatterer of different size,are demonstrated with the phononic crystal *** work provides a practical platform for implementing full-parameter transformation acoustics,opening avenues for versatile applications such as advanced acoustic imaging and stealth technologies.

关键词： phononic crystals transformation acoustics omnidirectional impedance matching configurable dispersion surfaces

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High-efficiently doping nitrogen in kapok fiber-derived hard carbon used as anode materials for boosting rate performance of sodium-ion batteries

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Journal of Energy Chemistry 2024年第9期96卷 472-482页

作者： Tianyun Zhang Tian Zhang Fujuan Wang Fen Ran School of Mechanical and Electronical Engineering Lanzhou University of TechnologyLanzhou 730050GansuChina State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals School of Materials Science and EngineeringLanzhou University of TechnologyLanzhou 730500GansuChina

The engineering of plant-based precursor for nitrogen doping has become one of the most promising strategies to enhance rate capability of hard carbon materials for sodium-ion batteries;however,the poor rate performance is mainly caused by lack of pyridine nitrogen,which often tends to escape because of high temperature in preparation process of hard *** this paper,a high-rate kapok fiber-derived hard carbon is fabricated by cross-linking carboxyl group in 2,6-pyridinedicarboxylic acid with the exposed hydroxyl group on alkalized kapok with assistance of zinc ***,a high nitrogen doping content of 4.24%is achieved,most of which are pyridine nitrogen;this is crucial for improving the defect sites and electronic conductivity of hard *** optimized carbon with feature of high nitrogen content,abundant functional groups,degree of disorder,and large layer spacing exhibits high capacity of 401.7 mAh g^(−1)at a current density of 0.05 A g^(−1),and more importantly,good rate performance,for example,even at the current density of 2 A g^(−1),a specific capacity of 159.5 mAh g^(−1)can be *** findings make plant-based hard carbon a promising candidate for commercial application of sodium-ion batteries,achieving high-rate performance with the enhanced pre-cross-linking interaction between plant precursors and dopants to optimize aromatization process by auxiliary pyrolysis.

关键词： Kapok fiber Hard carbon Electrode materials Rate performance Sodium-ion batteries

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Spatial phase structure and oxidation process of Al-W alloy powder with high sphericity

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Journal of materials Science & technology 2022年第19期114卷 62-72页

作者： Aobo Hu Shuizhou Cai State Key Laboratory of Material Processing and Die&Mould Technology The School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

In this study,Al-30W(wt.%)alloy powder was prepared by Aluminothermic reduction and hightemperature gas *** then studied the phase composition,surface morphology,spatial phase structure,and thermal oxidation process using XRD,SEM/EDS,TEM,DSC,and DTA/TG *** results showed that the Al-30W alloy powder exhibited high sphericity,and the interior presented a special spatial phase structure in which the Al/W amorphous alloy phase and the metastable Al/W intermetallic compound phase were distributed in the pure Al *** the Al-30W alloy powder was stabilized in a vacuum tube furnace,the spatial phase structure of the alloy powder changed,and a small amount of pure Al was embedded in the Al_(12)W *** resulting Al-30W alloy powder products,treated in air at different temperatures,were collected in situ and *** results presented that with an increase in temperature,the types and morphologies of the Al/W intermetallic compounds in the Al-30W alloy powder ***,the Al-30W alloy powder began to undergo intense oxidation reactions at about 900℃,accompanied by a concentrated energy release and rapid weight *** volatilization of WO_(3)produced in the oxidation process promoted the complete oxidation of the Al-30W alloy powder,and the Al-30W alloy powder was completely oxidized at 1300℃.At this stage,all W atoms were transformed into gaseous WO_(3),and only a large number of small Al_(2)O_(3)fragments remained in the oxidation ***,the Al-30W alloy powder exhibited excellent thermal reactivity and oxidation integrity,and may offer excellent application prospects in the field of energetic materials.

关键词： Aluminothermic reduction High-temperature gas atomization Al/W amorphous alloy phase Metastable Al/W intermetallic compound phase Thermal oxidation process

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Robust double-layered ANF/MXene-PEDOT:PSS Janus films with excellent multi-source driven heating and electromagnetic interference shielding properties

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Nano Research 2022年第10期15卷 9520-9530页

作者： Bing Zhou Jianzhou Song Bo Wang Yuezhan Feng Chuntai Liu Changyu Shen Key Laboratory of Materials Processing and Mold Ministry of Education National Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China

The strategy of incorporating polymers into MXene-based functional materials has been widely used to improve their mechanical properties,however with inevitable sacrifice of their electrical conductivity and electromagnetic interference(EMI)shielding *** study demonstrates a facile yet efficient layering structure design to prepare the highly robust and conductive double-layer Janus films comprised of independent aramid nanofiber(ANF)and Ti3C2Tx MXene/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)(PEDOT:PSS)*** ANF layer serves to provide good mechanical stability,whilst the MXene/PEDOT:PSS layer ensures excellent electrical *** PEDOT:PSS into the MXene layer enhances the interfacial bonding strength between the MXene and ANF layers and improves the hydrophobicity and water/oxidation resistance of MXene *** resultant ANF/MXene-PEDOT:PSS Janus film with a conductive layer thickness of 4.4μm was shown to display low sheet resistance(2.18Ω/sq),good EMI shielding effectiveness(EMI SE of 48.1 dB),high mechanical strength(155.9 MPa),and overall toughness(19.4 MJ/m^(3)).Moreover,the excellent electrical conductivity and light absorption capacity of the MXene-PEDOT:PSS conductive layer mean that these Janus films display multi-source driven heating functions,producing excellent Joule heating(382℃ at 4 V)and photothermal conversion(59.6℃ at 100 mW/m^(2))properties.

关键词： MXene double-layer structure mechanical properties electromagnetic interference(EMI)shielding electro-/photothermal conversion

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Origin of low lattice thermal conductivity in promising ternary Pb_(m)Bi_(2)S_(3+m)(m=1-10)thermoelectric materials

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Journal of materials Science & technology 2024年第31期198卷 12-19页

作者： Wei Liu Biao Chen Liqing Xu Dongyang Wang Changsheng Xiang Xiangdong Ding Yu Xiao State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong UniversityXi'an 710049China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi'an 710072China School of Materials and Energy University of Electronic Science and Technology of ChinaChengdu 611731China Henan Key Laboratory of Diamond Optoelectronic Materials and Devices Key Laboratory of Material PhysicsMinistry of EducationSchool of PhysicsZhengzhou UniversityZhengzhou 450052China

Ternary Pb-Bi-S compounds emerge as potential thermoelectric materials owing to low thermal conductivity,but the origin of their intrinsic low lattice thermal conductivities lacks further ***,a series of ternary Pb_(m)Bi_(2)S_(3+m)(m=1-10)compounds are synthesized and their crystal structure evolutions with increasing m values are clearly *** room-temperature lattice thermal conductivities in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9) can reach at 0.57,0.56 and 0.80 W m^(-1) K^(-1),respectively,outperforming other ternary sulfur-based *** calculations show that the low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)mainly originate from soft phonon dispersion caused by strong lattice anharmonicity,and both asymmetric chemical bond and lone pair electrons(Pb 6s2 and Bi 6s2)can favorably block phonon ***,the elastic measurements also confirm relatively low sound velocities and shear modulus,and the Grüneisen parameter(γ)calculated by sound velocities can reach at 1.67,1.85 and 1.94 in PbBi_(2)S_(4),Pb_(3)Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),***,the intrinsic low lattice thermal conductivities in Pb_(m)Bi_(2)S_(3+m)(m=1-10)contribute to promising thermoelectric performance,and the maximum ZT values of 0.47,0.38 and 0.45 can be achieved in undoped PbBi_(2)S_(4),Pb3Bi_(2)S_(6) and Pb_(6)Bi_(2)S_(9),respectively.

关键词： Crystal structure evolution Lattice thermal conductivity Phonon dispersion Lattice anharmonicity Lone pair electrons

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A double crosslinking MXene/cellulose nanofiber layered film for improving mechanical properties and stable electromagnetic interference shielding performance

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Journal of materials Science & technology 2022年第34期129卷 127-134页

作者： Shilu Luo Tiantian Xiang Jingwen Dong Fengmei Su Youxin Ji Chuntai Liu Yuezhan Feng Key Laboratory of Materials Processing and Mold Ministry of Education National Engineering Research Center for Advanced Polymer Processing TechnologyZhengzhou UniversityZhengzhou 450002China

With the discovery of the two-dimensional(2D) MXene, it shows a great application potential in the field of electromagnetic interference(EMI) shielding, but the mechanical brittleness and easy oxidation of MXene limit its wide application. For this reason, a double crosslinking strategy is provided to solve the above problems in a nacre-like “brick-mortar” layered MXene/cellulose nanofiber(MXene/CNF) ***, the film was firstly suffered by dopamine modification, then was further reinforced by secondary Ca^(2+)bridging, so as to obtain excellent mechanical properties and antioxidative EMI shielding performance. Comparing with the single crosslinking, the double crosslinking strategy reveals a higher efficiency in improving the mechanical property. The mechanical strength and toughness of the double crosslinking MXene/CNF film can increase to 142.2 MPa and 9.48 MJ/m^(3), respectively. More importantly, while achieving good mechanical properties, the MXene composite film still holds a very stable EMI shielding performance of more than 44.6 dB when suffering from the oxidation treatment of hightemperature annealing, showing excellent anti-oxidation ability and environment tolerance. Therefore,this work provides a universal but effective double crosslinking strategy to solve the mechanical brittleness and easy oxidation of MXene-based composites, thus showing a huge potential in flexible EMI shielding applications.

关键词： Ti_(2)C_(3)T_(x)MXene Layered structure Double crosslinking Mechanical properties EMI shielding performance

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Improvement of the microstructure and magnetic properties of(La,Ce)-Fe-B nanocrystalline ribbons

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Chinese Physics B 2023年第7期32卷 521-529页

作者：连李昱张晓伟刘颖李军王仁全 School of Materials Science and Engineering Sichuan UniversityChengdu 610065China Key Laboratory of Advanced Special Material&Technology Ministry of EducationSichuan UniversityChengdu 610065China

The obstacles of inferior microstructure and poor magnetic properties of(La,Ce)-Fe-B type magnets stand in the way of expanding their *** this work,(La,Ce)-Fe-B melt-spun ribbons were prepared with different La/Ce ratios and rare earth *** microstructure and magnetic properties of these ribbons were *** the La/Ce ratio increased,the fraction of the CeFe_(2)phase decreased and the β-La phase segregated among matrix grains,which deteriorated the coercivity of the *** the rare earth content effectively suppressed the β-La phase and improved the proportion of the matrix phase in the ***,the optimal alloy composite(La_(15)Ce_(85))_(14)Fe_(80)B_(6) has been obtained with modified microstructure and inhibited secondary *** ribbon performance was tested,with H_(cj)=4.51 kOe,B_(r)=6.29 kG and(BH)_(max)=6.81 MGOe.

关键词： (La,Ce)-Fe-B La/Ce ratio rare earth content secondary phases inhibition

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Pd-La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)composite as active and stable oxygen electrode for reversible solid oxide cells

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Journal of Rare Earths 2023年第4期41卷 599-604页

作者： Rui Yang Yunfeng Tian Yun Liu Jian Pu Bo Chi Center for Fuel Cell Innovation State Key Laboratory of Material Processing and Die&Mould TechnologyHuazhong University of Science and TechnologyWuhan 430074China Jiangsu Key Laboratory of Coal-based Greenhouse Gas Control and Utilization School of Materials Science and PhysicsChina University of Mining and TechnologyXuzhou 221116China

To promote the electrocatalytic activity and stability of traditional(a_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)(LSCF)oxygen electrodes in reversible solid oxide cells(RSOCs),conventional physical mixed method was used to prepare the Pd-LSCF composite oxygen *** cell with Pd-LSCF|GDC|YSZ|Ni-YSZ configuration shows perfect electrochemical performance in both solid oxide fuel cell(SOFC)mode and solid oxide electrolysis cell(SOEC)*** the SOFC mode,the cell achieves a power density of 1.73 W/cm^(2)at800℃higher than that of the LSCF oxygen electrode with 1.38 W/cm^(2).In the SOEC mode,the current density at 1.5 V is 1.67 A/cm^(2)at 800℃under 50 vol%steam ***,the reversibility and stability of the RSOCs were tested during 192 h long-term reversible *** degradation rate of the cell is only 2.2%/100 h and 2.5%/100 h in the SOEC and the SOFC modes,*** results confirm that compositing Pd with the LSCF oxygen electrode can considerably boost the electrochemical performance of LSCF electrode in RSOCs field.

关键词： Reversible solid oxide cells Composite Oxygen electrode La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ) Electrochemical performance Rare earths

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A new thiol-sulfur click chemistry for lithium-organosulfide batteries

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The Innovation 2025年第2期6卷 42-48,41页

作者： Rong Zou Wenwu Liu Fen Ran State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals Department of Polymeric Materials EngineeringSchool of Materials Science and EngineeringLanzhou University of TechnologyLanzhou 730050China

Click chemistry is a rapid,reliable,and powerful function and a highly selective organic reaction that facilitates the efficient synthesis of various molecules by joining small *** approach has found widespread applications in fields such as drug development,chemical synthesis,and molecular *** recent years,the reaction of alkali-catalyzed polymerization of thiol and sulfur has been employed to prepare various sulfur-containing polymers,which are applied as electrochemical active electrode materials in the pursuit of good *** this study,it is surprising to find that the reaction mechanism exhibits characteristics of both the alkali-catalyzed sulfhydryl Micheal addition reaction and thiol-epoxy click chemistry;for the first time,thiol-sulfur click chemistry is defined in detail,providing a comprehensive description of its underlying scientific *** introduction of this new reaction pathway holds significant potential for advancing research and the development of sulfur-containing *** on this novel click chemistry,a new sulfur-containing polymer,polydivinylthioether hexasulfide,has been designed and successfully applied as a cathode material in lithium-organosulfide *** material demonstrates excellent electrochemical performance,achieving an initial capacity that reaches 790.5 mAh g−1(82.6%of theoretical capacity),and in a long-term cycle test,the capacity decay rate is only 0.063%after 1,000 cycles.

关键词： electrochemical active electrode mater thiol sulfur click chemistry molecular biologyin lithium organosulfide batteries synthesis various molecules organic reaction click chemistry joining small unitsthis

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