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Phase field modeling of ferroelastic variant switching in yttria-stabilized t'zirconia with strain gradient elasticity and interface tension

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Science China(Technological Sciences) 2024年第5期67卷 1443-1457页

作者： ZHOU QianQian WEI yueguang ZHOU YiChun YANG Li College of Engineering BIC-ESATPeking UniversityBeijing100871China School of Advanced Materials and Nanotechnology Xidian UniversityXi’an710126China Frontier Research Center of Thin Films and Coatings for Device Applications Academy of Advanced Interdisciplinary ResearchXidian UniversityXi’an710126China

The 6–8 wt%yttria-stabilized zirconia with a tetragonal structure(t’-YSZ)is extensively employed in thermal barrier *** exceptional fracture toughness of t’-YSZ can be attributed to its distinctive ferroelastic toughening *** and interface tension play a critical role in ferroelastic variant switching at the micro-and *** paper presents an original thermodynamically consistent phase field(PF)theory for analyzing ferroelastic variant switching at the micro-and nano-scale of t’-*** theory incorporates strain gradient elasticity using higher-order elastic energy and interface tension tensor via geometric nonlinearity to represent biaxial tension resulting from interface ***,a mixed-type formulation is employed to implement the higher-order theory through the finite element *** an interface in equilibrium,the effects of strain gradient elasticity result in a more uniform distribution of stresses,whereas the presence of interface tension tensor significantly amplifies the stress magnitude at the *** introduction of an interface tension tensor increases the maximum value of stress at the interface by a factor of 4 to *** nucleation and evolution of variants at a pre-existing crack tip in a mono-phase t’-YSZ have also been *** strain gradient elasticity is capable of capturing the size effect of ferroelastic variant switching associated with microstructures in ***,when the grain size approaches that of the specimen,the critical load required for variant switching at the crack tip increases,resulting in greater dissipation of elastic energy during ferroelastic variant ***,the interface tension accelerates the evolution of *** presented framework exhibits significant potential in modeling ferroelastic variant switching at the micro-and nano-scale.

关键词： thermodynamics strain gradient elasticity interface tension phase field method ferroelastic variant switching

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Effects of Mg on Mechanical Properties of 35CrNi3MoV Steel

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Journal of Materials Science & Technology 1998年第2期14卷 104-108页

作者： yu, yueguang Fu, Jie Wang, Anren Chen, Boping Sun, Wenshan Univ Sci & Technol Beijing Beijing 100083 Peoples R China Inner Mongolia Metall Mat Res Inst Baotou 014034 Peoples R China

The results show that Mg has less effect on the tensile properties and hardness of the steel at room temperature, but a right amount of Mg improves impact and fracture toughness and decreases the fracture-transition temperature considerably due to inclusions modification, as well as prolongs the notch stress rupture life dramatically through strengthening grain boundary and modifying boundary carbides. There is an optimum Mg content, which is about 0.0030% in the experimental 35CrNi3MoV steel. (Edited author abstract) 8 Refs.

关键词： Steel

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Aluminum Control in CrNiMoV Steel during Electroslag Remelting Process

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International Journal of Minerals,Metallurgy and Materials 1998年第2期12卷 87-89页

作者： Anren Wang yueguang yu Jie Fu Metallurgy School, UST Beijing, Beijing 100083, China Metallurgy School UST Beijing Beijing 100083 China

The residual aluminum content has a great influence upon CrNiMoV steel properties and the optimal content is about 0.010%. The aluminum control during the ESR process has been investigated in this paper. All experiments were car ried out in a 20 kg ESR furnace. The results show that when a 60%CaF_2-30%Al_2O_3-5%SiO_2-5%CaO slag system and proper deoxidizing schedule is used, a reasonable ingot with optimal aluminum contents can be obtained. Silicon and magnesium contents are approximately the same with those in the electrode.

关键词： ESR aluminum CrNiMoV steel

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Ligand effect in surface atomic sites of group VI B transition metals on ultrathin Pt nanowires for enhanced oxygen reduction

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Nano Research 2024年第6期17卷 5298-5304页

作者： yuwei He yueguang Chen Renjie Wu Zhihe Xiao Mengxian Li Chunfeng Shi Leyu Wang State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Petroleum Molecular and Process Engineering SINOPEC Research Institute of Petroleum Processing Co.Beijing 100083China

Increasing the utilization efficiency of platinum is critical for advancing proton exchange-membrane fuel cells(PEMFCs).Despite extensive research on catalysts for the cathodic oxygen reduction reaction(ORR),developing highly active and durable Pt-based catalysts that can suppress surface dealloying in corrosive acid conditions remains ***,we report a facile synthesis of bimetallic ultrathin PtM(M=Mo,W,and Cr)nanowires(NWs)composed of group VI B transition metal atomic sites anchored on the *** NWs possess uniform sizes and well-controlled atomic *** to PtW and PtCr catalysts,the PtMo0.05 NWs exhibit the highest half-wave potential of 0.935 V and a mass activity of 1.43 A·mgPt^(−1).Remarkably,they demonstrate a remarkable 23.8-fold enhancement in mass activity compared to commercial Pt/C for ORR,surpassing previously reported Pt-based ***,the PtMo NWs cathode in membrane electrode assembly tests achieves a remarkable peak power density of 1.443 W·cm^(−2)(H_(2)-O_(2)conditions at 80℃),which is 1.09 times that of commercial Pt/*** ligand effect in the bimetallic surface not only facilitates strong coupling between Mo(4d)and Pt(5d)atomic orbitals to hinder atom leaching but also modulates the d-states of active site,significantly optimizing the adsorption of key oxygen(*O and*OH)species and accelerating the rate-determining step in ORR pathways.

关键词： ligand effect oxygen reduction reaction group VI B transition metal ultrathin nanowires multiple oxygen species

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Phase-transfer interface promoted corrosion from PtNi10 nanoctahedra to Pt4Ni nanoframes

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纳米研究：英文版 2015年第1期8卷 140-155页

作者： yu Wang yueguang Chen Caiyun Nan Lingling Li Dingsheng Wang Qing Peng Yadong Li Department of Chemistry Tsinghua University Beijing 100084 China

向 PtNi 的腐蚀的一条新奇二阶段的途径 10 nanoctahedra 被开发了。在这策略，在油可溶的 PtNi 的 Ni 的活跃部件居住在上面的甲苯阶段，受不了蚀刻并且是的 10 nanoctahedra 然后由 ethylenediaminetetraacetate (EDTA ) 与协作... 详细信息

向 PtNi 的腐蚀的一条新奇二阶段的途径 10 nanoctahedra 被开发了。在这策略，在油可溶的 PtNi 的 Ni 的活跃部件居住在上面的甲苯阶段，受不了蚀刻并且是的 10 nanoctahedra 然后由 ethylenediaminetetraacetate (EDTA ) 与协作转了进一个更低的水的阶段。由于 EDTA 支持的阶段转移接口的存在，腐蚀反应在温和条件下面以加速的率继续了。明确地，八面的磅的结果的产品 4 Ni nanoframes 成功地第一次被制作，并且 PtNi 4 当 EDTA-2Na 的剂量被减少时，多孔的 octahedra 能被获得。在这个二阶段的系统的系统的研究以后，合作腐蚀机制被建议说明八面的磅的形成 4 Ni nanoframes ，从许多种类包含贡献(即， O 2 , H 2 O ， H +, OAm ，和 EDTA 4 )。由于磅的迷人的三维的几何学 4 Ni nanoframes 和 PtNi 4 多孔的 octahedra ，两个在太古的 PtNi 上侵蚀的 nanocrystals 显示出优异活动为在硝基苯的碱的媒介和加氢的乙醇 electrooxidation 的 10 nanoctahedra 。

关键词：腐蚀反应相转移 EDTA-2Na 接口活性成分八面体两相体系几何形状

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OH regulator of highly dispersed Ru sites on host Pd nanocrystals for selective ethanol electro-oxidation

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Nano Research 2024年第5期17卷 3863-3871页

作者： Zhihe Xiao yueguang Chen Renjie Wu yuwei He Chunfeng Shi Leyu Wang State Key Laboratory of Chemical Resource Engineering College of ChemistryBeijing University of Chemical TechnologyBeijing 100029China Research Institute of Petroleum Processing SINOPECBeijing 100083China

The ethanol oxidation reaction(EOR)is crucial in direct alcohol fuel cells and chemical ***,the electro-oxidation of ethanol molecules to produce acetaldehyde and carbon monoxide can poison the active sites of nanocatalysts,resulting in reduced performance and posing challenges in achieving high activity and selectivity for ethanol *** this study,we employed a dynamic seed-mediated method to precisely modify highly dispersed Ru sites onto well-defined Pd *** oxyphilic Ru sites serve as"OH valves",regulating water dissociation,while the surrounding Pd atomic arrangements control electronic states for the oxidation dehydrogenation of carbonaceous ***,Ru0.040@Pd nanocubes(Ru:Pd=0.04 at.%),featuring(100)facets in Ru-Pd4 configurations,demonstrate an outstanding mass activity of 6.53 A·mgPd^(-1) in EOR under alkaline conditions,which is 6.05 times higher than that of the commercial Pd/C catalyst(1.08 A·mgPd-1).Through in-situ experiments and theoretical investigations,we elucidate that the hydrophilic Ru atoms significantly promote the dynamic evolution of H_(2)O dissociation into OHads species,while the electron redistribution from Ru to adjacent Pd concurrently adjusts the selective oxidation of C_(2) *** host-guest interaction accelerates the subsequent oxidation of carbonaceous intermediates(CH_(3)CO_(ads))to acetate,while preventing the formation of toxic*CHx and*CO species,which constitutes the rate-determining step.

关键词： OH regulator atomic sites ethanol electro-oxidation host-guest interaction

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Segregation Behaviour and Microstructure of Alloy 718VADER Ingot

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Journal of Materials Science & Technology 1994年第6期10卷 406-410页

作者： yueguang yu Jie FU and Xishan XIE(University of Science and Technology Bejing, Beijing, 100083, China)Jialong XU and Chunyong JING(Shanghai Iron and Steel Research Institute, Shanghai, 200940, China) Univ of Science and Technology Beijing Beijing China

The segregation behaviour and miclostructure of an alloy 718 VADER ingot in comparison with a VAR ingot were studied. The results show that one serious problem of the alloy 718 VADER ingot is dealing with radial chemistry gradients (especially macro-segregation in Nb). The main factor of Nb gradient forming is the flow of Nb rich fluid through passages among the cellular structures driven by centrifugal force from the rotating mold, Detailed structure and micro-segregation studies on ingots impress us that the VADER process does not show the advantage on the improvement of micro-segregation especially in Nb. The cellular structure produced by the VADER process is no more effective in reducjng Nb micro-segregation during homogenization treatment than the dendritic structure by the VAR process. Experimental results lead us to believe that the VADER process is unsuitable to manufacture alloy 718.

关键词： Segregation Behaviour and Microstructure of Alloy 718VADER Ingot

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(Cr,Fe)_(7)C_(3)颗粒原位自生的Fe_(3)Al基金属陶瓷涂层磨损行为

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有色金属工程 2022年第10期12卷 17-27页

作者：袁建鹏于月光沈婕东北大学沈阳110006 矿冶科技集团有限公司北京100160 特种涂层材料与技术北京市重点实验室北京102206

制备研究了一种以Fe_(3)Al金属间化合物为基相,原位自生(Cr,Fe)_(7)C_(3)颗粒为陶瓷相的新型低成本金属陶瓷涂层及其摩擦磨损性能。通过投料成分的精准设计,采用真空冶金+堕气雾化的冶金方法直接制备了(Cr,Fe)_(7)C_(3)/Fe_(3)Al新型复... 详细信息

制备研究了一种以Fe_(3)Al金属间化合物为基相,原位自生(Cr,Fe)_(7)C_(3)颗粒为陶瓷相的新型低成本金属陶瓷涂层及其摩擦磨损性能。通过投料成分的精准设计,采用真空冶金+堕气雾化的冶金方法直接制备了(Cr,Fe)_(7)C_(3)/Fe_(3)Al新型复合粉末,获得碳化物原位自生于Fe_(3)Al基相且呈弥散分布的(Cr,Fe)_(7)C_(3)/Fe_(3)Al金属陶瓷涂层原料;采用超音速火焰喷涂(HVOF)制备(Cr,Fe)_(7)C_(3)/Fe_(3)Al涂层,并通过销-盘往复干摩擦磨损实验,研究了具有原位自生(Cr,Fe)_(7)C_(3)颗粒弥散强化的(Cr,Fe)_(7)C_(3)/Fe_(3)Al金属陶瓷涂层在室温及400℃下的耐摩擦磨损性能。结果表明:(Cr,Fe)_(7)C_(3)/Fe_(3)Al涂层的结合强度达到60.51 MPa,涂层硬度随温度升高衰减较慢,且在室温和400℃相应实验条件下的摩擦系数分别为0.7722和0.5634,均明显低于RuT350铸铁基体摩擦系数,400℃下其摩擦副的总磨损量仅为RuT350基体摩擦副总磨损量的50.4%,耐磨性优于Fe_(3)Al涂层和NiCr-Mo-Cr_(3)C_(2)涂层。(Cr,Fe)_(7)C_(3)/Fe_(3)Al具有较高的中高温耐磨性主要源于金属间化合物Fe_(3)Al黏结相在特定的温度范围具有异于普通合金的R现象,促使(Cr,Fe)_(7)C_(3)/Fe_(3)Al具有较高的高温硬度,并存在大量弥散分布的细小(Cr,Fe)_(7)C_(3)晶粒,不易造成陶瓷颗粒从金属相中脱落在磨损表面形成第三粒的协同机制。研制的(Cr,Fe)_(7)C_(3)/Fe_(3)Al涂层新材料在400℃左右的中低温下具有优异的耐摩擦磨损性能,且原材料成本低,具有工业应用潜力。

关键词：耐磨性涂层摩擦系数原位自生 Cr_(7)C_(3)/Fe_(3)Al 磨损机制

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杂质对氧化锆热障涂层性能的影响

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无机材料学报 2020年第6期35卷 669-674页

作者：冀晓鹃于月光卢晓亮东北大学材料科学与工程学院沈阳110819 北京矿冶科技集团有限公司北京100160

降低热障涂层面层中的低熔点杂质含量,可提高涂层的高温稳定性和延长服役寿命。SiO2、Al2O3和Fe2O3是氧化钇稳定氧化锆(Yttria-Stabilized Zirconia,YSZ)热障涂层中几种常见的低熔点氧化物杂质,均会对涂层的性能产生一定的影响。本研究... 详细信息

降低热障涂层面层中的低熔点杂质含量,可提高涂层的高温稳定性和延长服役寿命。SiO2、Al2O3和Fe2O3是氧化钇稳定氧化锆(Yttria-Stabilized Zirconia,YSZ)热障涂层中几种常见的低熔点氧化物杂质,均会对涂层的性能产生一定的影响。本研究采用大气等离子喷涂法,制备SiO2、Al2O3和Fe2O3的含量从小于0.01wt%增加至1.00wt%的YSZ热障涂层。采用扫描电镜(SEM)和透射电镜(TEM)研究了上述涂层的微观结构;采用激光热导仪测试了涂层的热扩散系数和抗热震次数。研究结果表明,低熔点氧化物杂质对YSZ涂层的导热性、热处理状态的孔隙率具有明显影响,且更容易引起涂层的热震失效。当杂质氧化物含量在小于0.2wt%范围内变化时,涂层的性能变化更为显著。

关键词：热障涂层杂质 YSZ 抗热震性能导热性

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Linear-Quadratic Pareto Cooperative Game for Mean-Field Backward Stochastic System

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Journal of Systems Science & Complexity 2024年第3期37卷 947-964页

作者： WANG yu School of Control Science and Engineering Shandong UniversityJinan 250061China

This paper focuses on a Pareto cooperative differential game with a linear mean-field backward stochastic system and a quadratic form cost functional. Based on a weighted sum optimality method, the Pareto game is equivalently converted to an optimal control problem. In the first place,the feedback form of Pareto optimal strategy is derived by virtue of decoupling technology, which is represented by four Riccati equations, a mean-field forward stochastic differential equation(MF-FSDE),and a mean-field backward stochastic differential equation(MF-BSDE). In addition, the corresponding Pareto optimal solution is further obtained. Finally, the author solves a problem in mathematical finance to illustrate the application of the theoretical results.

关键词： Backward stochastic differential equation linear-quadratic control mean-field Pareto optimality

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