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Oxidation Performance and Interdiffusion Behaviour of two McrAlY coatings on a Fourth-Generation Single-crystal Superalloy

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Acta Metallurgica Sinica(English Letters) 2022年第4期35卷 679-692页

作者： K.J.Tan J.J.Liang x.G.wang x.P.Tao J.Gong c.Sun Y.Z.Zhou x.F.Sun Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China

The oxidation behaviour of a fourth-generation single-crystal superalloy without coating and with two types of McrAlY coatings at 1140℃was *** results showed that both coatings greatly improved the oxidation resistance of the superalloy,and the addition of Hf further improved the oxidation resistance by pinning the oxide layer into the *** and after oxidation,obvious cr and Al interdiffusion was *** cr diffusion induces the precipitation of a topologically close-packed phase,while the diffusion of Al affects the structure of theγ/γ’phase,the solubility of refractory elements,and the formation of an interdiffusion zone.

关键词： Superalloys Metal coatings Oxidation Electron probe microanalyser(EPMA) Element diffusion

DETERMINATION AND APPLIcATION OF LARSON-MILLER PARAMETER FOR HEAT RESISTANT STEEL 12crlMoV AND 15crMo

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 471-476页

作者： R.c.Yang K.chen H.x.Feng H.wang State Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050ChinaState Key Lab. of Advanced Nonferrous Materials Lanzhou University of Technology Lanzhou 730050China

Based on the analysis and processing on relative empirical formula and data, c-values in Larson-Miller (P) expression, P= T(c + Igt), have determined for pearlitic heat resistant steel 12cr1MoV and 15crMo(20.62 and 20.30). The simulation experiments of high temperature aging, heated from 1.5 to 873 hours, have been designed and performed for its verification. And in combination with published information and the present nearly quantitative works, it has further been verified that both the degradations of microstructures and mechanical properties show a good accuracy and practicability using the Larson-Miller parameter with the present determined c-values. Finally, the effects of carbon content on c-value are analyzed by the empirical electron theory of solids and molecules (EET).

关键词： pearlitic heat-resistant steel Larson-Miller parameter aging valence electron structure

Preparation of co/S co-doped carbon catalysts for excellent methylene blue degradation

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International Journal of Minerals,Metallurgy and Materials 2025年第1期32卷 169-181页

作者： Haixu Li Haobo He Tiannan Jiang Yunfei Du Zhichen Wu Liang xu xinjie wang xiaoguang Liu Wanhua Yu Wendong xue School of Materials Science and Engineering University of Science and Technology BeijingBeijing 100083China Beijing Jinyu Tongda Refractory Technologies co. Ltd.Beijing 100085China

S and co co-doped carbon catalysts were prepared via pyrolysis of MOF-71 and thiourea mixtures at 800℃at a mass ratio of MOF-71 to thiourea of 1:0.1 to effectively activate peroxymonosulfate(PMS)for methylene blue(MB)*** effects of two different mixing routes were identified on the MB degradation ***,the catalyst obtained by the alcohol solvent evaporation(MOF-AEP)mixing route could degrade 95.60%MB(50 mg/L)within 4 min(degradation rate:K=0.78 min^(-1)),which was faster than that derived from the direct grinding method(MOF-DGP,80.97%,K=0.39 min^(-1)).x-ray photoelectron spectroscopy revealed that the co-S content of MOF-AEP(43.39at%)was less than that of MOF-DGP(54.73at%),and the proportion of c-S-c in MOF-AEP(13.56at%)was higher than that of MOF-DGP(10.67at%).Density functional theory calculations revealed that the adsorption energy of co for PMS was -2.94 eV when sulfur was doped as c-S-c on the carbon skeleton,which was higher than that when sulfur was doped next to cobalt in the form of co-S bond(-2.86 eV).Thus,the c-S-c sites might provide more contributions to activate PMS compared with ***,the degradation parameters,including pH and MOF-AEP dosage,were ***,radical quenching experiments and electron paramagnetic resonance(EPR)measurements revealed that ^(1)O_(2)might be the primary catalytic species,whereas·O~(2-)might be the secondary one in degrading MB.

关键词： advanced oxidation process alcohol solvent evaporation hydrogen bond S and co co-doped carbon catalysts wastewater remediation

A quasi-in-situ EBSD study of the thermal stability and grain growth mechanisms of cocrNi medium entropy alloy with gradient-nanograined structure

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Journal of Materials Science & Technology 2022年第14期109卷 54-63页

作者： P.-c.Zhao B.Guan Y.-G.Tong R.-Z.wang x.Li x.-c.Zhang S.-T.Tu Key Laboratory of Pressure Systems and Safety Ministry of EducationSchool of Mechanical and Power EngineeringEast China University of Science and TechnologyShanghai 200237China college of Materials Science and Engineering Chongqing UniversityChongqing 400044China college of Automobile and Mechanical Engineering Changsha University of Science and TechnologyChangshaChina

The thermal stability and mechanical properties of a gradient-nanograined structure(GNS)cocrNi medium entropy alloy(MEA)processed by ultrasonic surface rolling were studied by using isothermal/isochronal annealing tests combined with quasi-in-situ electron backscatter diffraction(EBSD)characterization and Vickers micro-hardness(HV)measurements.A layer by layer high-throughput investigation method was used to quantitatively study the grain growth kinetics and grain boundary evolution with different initial grain sizes,which could effectively save specimen and time *** grain nucleation and growth,as well as shrink and disappearance process throughΣ3 coincidence site lattice boundary migration with slightly lattice rotation during annealing were directly *** layer by layer grain growth kinetics and calculated activation energy indicate that the thermal stability of nanograined top surface layer is relatively higher than that of nano-twined subsurface layer for the gradient cocrNi MEA processed by ultrasonic surface *** analysis show that the grain boundary relaxation and dynamic recrystallization of the topmost nano-grains led to the decrease of grain boundary energy,thus improving their thermal *** present work provided theoretical basis for the application of cocrNi MEA at high ***,the high-throughput method on the investigation of grain stability by using gradient structure can be easily extended to other materials and it is of great significance for understanding the microstructural evolution of gradient materials.

关键词： Medium entropy alloy Grain growth Gradient materials Nanostructured materials Annealing High throughput

cobalamin-dependent radical S-adenosyl-L-methionine protein functions with a partner to successively methylate tricyclic indole alkaloid for chuangxinmycin maturation and derivatization

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Science china chemistry 2025年第1期68卷 308-316页

作者： Sili wang Jiancheng Huang Yanan Du Wei Huang Yufeng xue xiaokun xu Guannan Zhong Yuanyuan Shi Bin Hong xiaoying Bian Wen Liu State Key Laboratory of chemical Biology Shanghai Institute of Organic Chemistry University of Chinese Academy of SciencesChinese Academy of Sciences State Key Laboratory of Microbial Technology Shandong University National Health commission (NHc) Key Laboratory of Biotechnology for Microbial Drugs Institute of Medicinal BiotechnologyChinese Academy of Medical Science & Peking Union Medical College

cobalamin(cbl)-dependent radical S-adenosyl-L-methionine(SAM) proteins constitute the largest collection of the radical SAM superfamily that has hundreds of thousands of individual members. Many of these proteins are involved in the biosynthesis of pharmaceutically important natural products to catalyze chemically demanding reactions. In the biosynthetic pathway of chuangxinmycin(cxM), a unique indole alkaloid antibiotic with potent anti-infective activity, functionalization of the characteristic thiopyrano[4,3,2-cd]indole scaffold by regio-and stereoselective c3-methylation is believed to rely on a cbl-dependent radical process, which, however, remained to be reconstituted biochemically. We here report the dissection of this enzymatic process, which requires the incorporation of cxm8, a cbl-dependent radical SAM protein, with cxm9, a DUF5825family protein that shares no homology to any proteins of known functions. cxm8 and cxm9 function together by forming an unexpected heterodimeric complex that selectively catalyzes c3-methylation of the tricyclic indole-S-hetero ring system in a successive manner, achieving cxM and a recently identified, c3-dimethylated congener. Detailed biochemical characterization,isotope labeling, structural simulation and bioinformatics analysis rationalized the catalysis of the cxm8/cxm9 complex and particularly the necessity of the DUF5825 protein for c3-methylase activity. This is the first example that a cbl-dependent protein acts with a partner to exhibit radical SAM activity.

关键词： cbl-dependent radical SAM protein biosynthesis chuangxinmycin stereoselective methylation

Preparation and study of novel mid-to-low-temperature phase-change molten salts

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Science china Technological Sciences 2025年

作者： chenxing REN Yifan wang xin HE chenghang ZHENG xiang GAO State Key Laboratory of clean Energy Utilization Zhejiang University Institute of carbon Neutrality Zhejiang University Baima Lake Laboratory Zhejiang University

Molten salts is a promising medium for heat storage and heat transfer due to their advantages of low cost, low steam pressure, high energy storage density and wide temperature range. In this paper, a new phase change mixture of molten salts with KNO3, NaNO3, Zncl2, NaF, Na2cO3, Nacl, and MgO as materials has been prepared through a plenty of experiments. The experimental results show that the melting point of some molten salts can be reduced to 202.9°c, and the decomposition temperature can reach 701.3°c. In addition, its thermophysical properties, including specific heat, viscosity and thermal stability, were measured and analyzed. The average specific heat of some molten salts is as high as 2.53 J/（g K）, and the average thermal conductivity is as high as 0.77 W/（m K）. In the 4-day short-term thermal stability test, the fluctuation of each parameter is minimal, and the overall thermal physical property is relatively stable. compared with the traditional phase change molten salt, the new hybrid molten salt has a significantly lower melting point, a further improvement in the decomposition temperature, specific heat and other comprehensive thermophysical properties, and a better overall economy, which has important application value in heat transfer and energy storage.

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The effects of fabrication atmosphere condition on the microstructural and mechanical properties of laser direct manufactured stainless steel 17-4 PH

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Journal of Materials Science & Technology 2019年第7期35卷 1315-1322页

作者： D.wang c.T.chi W.Q.wang Y.L.Li M.S.wang x.G.chen Z.H.chen x.P.cheng Y.J.xie Institute of Applied Physics Jiangxi Academy of SciencesNanchang 330029China Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Mechanical and Electrical Engineering Nanchang UniversityNanchang 330029China Jiangxi Reman Additive Technology co. Ltd Nanchang 330096China

The effects of atmosphere conditions on microstructural and mechanical properties of stainless steel 17-4PH components fabricated by laser direct manufacturing (LDM) were investigated through mea-surements on phase constitution, porosity, tensile strength, fracture morphology, hardness and evolution of substrate temperature. Results showed that the samples produced in air atmosphere condition pos-sessed higher tensile strength and hardness for both as-deposited and heat-treated states than that in Ar chamber condition, due to dispersion strengthening effect of amorphous oxide particles and nitrogen solution strengthening as a result of higher content of oxygen and nitrogen. The temperature of substrate heat accumulation was higher in Ar chamber condition, leading to dramatically lower porosity and more reverse austenite, which also contributed to the lower strength and hardness.

关键词： Additive manufacturing Laser direct manufacturing 17-4 PH stainless steel Fabrication atmosphere Mechanical properties

Electromechanical modeling and experimental analysis of a compression-based piezoelectric vibration energy harvester

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International Journal of Smart and Nano Materials 2014年第3期5卷 152-168页

作者： x.Z.Jiang Y.c Li J.wang J.c.Li centre for Built Infrastructure Research Faculty of Engineering and Information TechnologyUniversity of Technology SydneyPO Box 12315 BroadwayUltimoNSW 2007Australia School of Mechanical Engineering Nanjing University of Science&Technology200 Xiaolingwei StreetXuanwu DistrictNanjing 210094China

Over the past few decades,wireless sensor networks have been widely used in the field of structure health monitoring of civil,mechanical,and aerospace ***,most wireless sensor networks are battery-powered and it is costly and unsustainable for maintenance because of the requirement for frequent battery *** an attempt to address such issue,this article theoretically and experimentally studies a compression-based piezoelectric energy harvester using a multilayer stack configuration,which is suitable for civil infrastructure system applications where large compressive loads occur,such as heavily vehicular loading acting on *** this article,we firstly present analytical and numerical modeling of the piezoelectric multilayer stack under axial compressive loading,which is based on the linear theory of piezoelectricity.A two-degree-of-freedom electromechanical model,considering both the mechanical and electrical aspects of the proposed harvester,was developed to characterize the harvested electrical power under the external electrical *** closed-form expressions of the electromechanical models have been derived to analyze the mechanical and electrical properties of the proposed *** theoretical analyses are validated through several experiments for a test prototype under harmonic *** test results exhibit very good agreement with the analytical analyses and numerical simulations for a range of resistive loads and input excitation levels.

关键词： vibration energy harvesting piezoelectric 2-DOF electromechanical model large-force low-frequency

GO/MgO/Mg interface mediated strengthening and electromagnetic interference shielding in AZ31 composite

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Journal of Magnesium and Alloys 2023年第10期11卷 3800-3814页

作者： Z.Y.xu c.F.Fang c.J.Li R.wang x.P.Zhang J.Tan Y.M.wang Key Laboratory of Solidification control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024China Faculty of Materials Science and Engineering Kunming University of Science and TechnologyKunming 650093China college of Materials Science and Engineering Chongqing UniversityChongqing 400045China Key Laboratory of Materials Modification by Laser Ion and Electron Beams(Ministry of Education)School of Materials Science and EngineeringDalian University of TechnologyDalian 116023China

More requirements of electromagnetic interference(EMI) shielding performance are put forward for lightweight structural materials due to the development of aerospace and 5G communications. Herein, graphene oxide(GO) decorated with SnO_(2) coating is introduced as reinforcement into AZ31 Mg alloy. During the smelting process, the MgO layer is in situ gernerated at interface between GO and the molten Mg alloy matrix by consuming SnO_(2). In the solid state, such kind of interface structure can improve the GO-Mg interface bonding intensity,also significantly generate stacking faults. The AZ31 composite reinfoced by trace modified GO(0.1 wt%) exhibits high ultimate strength and almost the same elongation with AZ31 alloy. compared with AZ31 alloy, the yield strength and ultimate tensile strength of composite are increased by 33.5% and 23.7%, respectively. Meanwhile, the multi-level electromagnetic reflection from the multi-layer structure of GO and the interface polarization caused by the MgO mid-layer can significantly improve EMI shielding performance. The appropriate interface design strategy achieves the effect of “two birds with one stone”.

关键词： Metal-matrix composites Mechanical properties EMI shielding Microstructures