检索结果-南通市图书馆

Sub-solvus Cellular Recrystallization and P Phase Formation in a Single-Crystal Superalloy Containing Re

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第1期28卷 72-76页

作者： Long-Chao Zhuo Ming Huang Ji-Chun Xiong Jia-Rong Li Jing Zhu The State Key Laboratory of New Ceramics and Fine Processing Laboratory of Advanced Materials (MOE) School of Materials Science and Engineering National Center for Electron Microscopy in Beijing Tsinghua University Science and Technology on Advanced high temperature Structural materials Laboratory Beijing Institute of Aeronautical Materials

Sub-solvus recrystallization behavior of a second-generation single-crystal superalloy has been studied by transmission electron microcopy and scanning transmission electron microcopy. Surface local stress facilitated cellular recrystallization accompanied with formation of twin structure and TCP phase of P during annealing at sub-solvus temperature of 1,100 °C. The precipitation of P phase is considered to be attributed to the coarsening of c0 phase in the recrystallized aggregates which lower the activation energy for atomic migration.

关键词： Nickel-based single-crystal superalloys Interfaces Recrystallization Twin boundary STEM

Effect of carbon addition on creep behavior of cast TiAl alloy with hard-oriented directional lamellar microstructure

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第11期27卷 1347-1356页

作者： Xi-wen Zhang Yu-ling Tang Wen-juan Wan Chun-lei Zhu Ji Zhang Beijing Key Laboratory of Advanced high temperature materials China Iron and Steel Research Institute GroupBeijing 100081China National center for Electron Microscopy in Beijing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Two TiAl alloys,Ti-47.5Al-3.7(Cr,V,Zr)and Ti-47.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were prepared by cold crucible levitation melting to couple the hard-oriented directional lamellar microstructure with carbon microalloying *** creep behavior and mechanism for the improvement in creep properties by carbon addition were investigated by mechanical tests and electron microscopy *** results show that obvious improvements on the creep properties at 760°C and 276 MPa are achieved by 0.1 at.%C addition into TiAl alloy with directional lamellar microstructure,which promotes the creep strain and minimum creep rate decreasing with a large *** minimum creep rate is reduced from 4.37×10^(-8) to 3.97×10^(-9) s^(-1),and the duration entering into creep acceleration is prolonged for more than 10 *** mechanism for creep property improvement by 0.1%C addition is attributed to two *** first one is that Ti_(2) AlC is found to be strong obstacles of 1/2[110]dislocations when moving across the lamellar interface in the carbon containing *** other one is that the in terfacial dislocatio ns are effectively impeded and the release process is hindered by dynamic precipitation of Ti_(3) AlC,which is proposed to be the special mechanism for creep resistance improvement of this hard-oriented directional lamellar microstructure.

关键词： Cast titanium aluminide Lamellar microstructure Creep behavior Carbon addition Dynamic precipitation

Effect of Re Addition and Withdrawal Rate on the Solidification Behavior of Directionally Solidified Superalloy AM3

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of materials Science & Technology 2011年第2期27卷 101-106页

作者： F.Long Y.S.Yoo S.M.Seo T.Jin Z.Q.Hu C.Y.Jo Institute of Metal Research Chinese Academy of SciencesShenyang 110016China high temperature materials Laboratory Korea Institute of Materials Sciences66 Sangnam-dongChangwonKyungunamKorea

The influence of Re addition and withdrawal rate on the solidification behavior of the first generation single crystal superalloy AM3 was investigated by directional solidification and quenching *** primary dendrite arm spacing and eutectic volume fraction were measured from directionally solidified superalloy AM3 with different Re *** is found that the primary dendrite arm spacing is determined by the withdrawal rate,and Re does not influence on the *** eutectic fraction increases with increasing Re *** coeffcients of alloying elements were investigated with energy-dispersive X-ray spectrometry（EDS） *** data was submitted to a statistical treatment to establish the solidification path,and the partition coeficients were measured by fitting the curve with a modified Scheil *** is shown that the addition of Re results in bigger microsegregation of alloying elements in directionally solidified AM3 superalloy.

关键词： Superalloy AM3 Re addation Directional solidification

Effect of carbon addition on stress rupture properties of a cast TiAl alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2019年第3期26卷 268-274页

作者： Xi-wen Zhang Yu-ling Tang Chun-lei Zhu Ji Zhang Beijing Key Laboratory of Advanced high temperature materials China Iron and Steel Research Institute Group Beijing 100081 China National center for Electron Microscopy in Beijing School of Materials Science and Engineering Tsinghua University Beijing 100084 China

Two TiAl alloys,Ti^47.5Al-3.7(Cr,V,Zr)and Ti77.5Al-3.7(Cr,V,Zr)-0.1C(at.%),were melted and cast with the same process,*** with strongly oriented lamellae were both observed in these two alloys followed by hot isostatic pressing and heat ***2AlC carbides were identified in the alloy with C *** rupture tests were carried out at 800 and 850°C,with tensile stress from 220 to 400 MPa,*** was shown that the alloy with C experienced much longer lives than the other,especially under the condition of 800°C/260 MPa,800°C/300 MPa,850°C/220 MPa,850°C/240 MPa and 850°C/260 *** of ruptured specimens revealed that the microstructure stability was improved significantly in the alloy with C addition which is attributed to the strengthening effect of Ti-Al-C *** Ti2AlC carbides mainly increased the resistance of dislocation passing through the interfaces and kept the integrity of the *** Ti3AlC carbide was formed during stress rupture process,which could not only effectively act as the barrier of dislocation movement inside the lamellae,but also strengthen the lamellae itself.

关键词： Titanium aluminide Carbon addition Stress rupture property Dynamic precipitated carbide

Optimizing high-coordination shell of Co-based single-atom catalysts for efficient ORR and zinc-air batteries

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of energy Chemistry 2024年第8期95卷 306-314,I0007页

作者： Yugang Qi Qing Liang Kexin Song Xinyan Zhou Meiqi Liu Wenwen Li Fuxi Liu Zhou Jiang Xu Zou Zhongjun Chen Wei Zhang Weitao Zheng Key Laboratory of Automobile materials MOE School of Materials Science&Engineering Electron Microscopy Centerand International Center of Future ScienceJilin Provincial International Cooperation Key Laboratory of High-Efficiency Clean Energy MaterialsJilin UniversityChangchun 130012JilinChina Institute of high energy Physics Chinese Academy of SciencesBeijing 100049China

Atom-level modulation of the coordination environment for single-atom catalysts(SACs)is considered as an effective strategy for elevating the catalytic *** the MNxsite,breaking the symmetrical geometry and charge distribution by introducing relatively weak electronegative atoms into the first/second shell is an efficient way,but it remains challenging for elucidating the underlying mechanism of ***,a practical strategy was reported to rationally design single cobalt atoms coordinated with both phosphorus and nitrogen atoms in a hierarchically porous carbon derived from metal-organic frameworks.X-ray absorption spectrum reveals that atomically dispersed Co sites are coordinated with four N atoms in the first shell and varying numbers of P atoms in the second shell(denoted as Co-N/P-C).The prepared catalyst exhibits excellent oxygen reduction reaction(ORR)activity as well as zinc-air battery *** introduction of P atoms in the Co-SACs weakens the interaction between Co and N,significantly promoting the adsorption process of ^(*)OOH,resulting in the acceleration of reaction kinetics and reduction of thermodynamic barrier,responsible for the increased intrinsic *** discovery provides insights into an ultimate design of single-atom catalysts with adjustable electrocatalytic activities for efficient electrochemical energy conversion.

关键词： Electrocatalytic Oxygen reduction reaction Single atom catalyst Shell coordination optimization

Microstructure stability of γ’+β Ni-Al coated single-crystal superalloy N5 annealed at 1100℃

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第3期40卷 693-700页

作者： Jing-Yong Sun Liang-Liang Wei Qiu-Shi Li Sheng-Kai Gong Hong-Bo Guo School of energy and Power Engineering Beihang UniversityBeijing 100191China School of materials Science and Engineering Beihang UniversityBeijing 100191China Key Laboratory of high-temperature Structural materials and Coatings Technology Ministry of Industry and Information TechnologyBeijing 100191China

γ’+β Binary-phase Ni-Al coatings were prepared on second-generation single-crystal superalloy Rene N5(N5) substrates by electron beam physical vapor ***-diffusion behavior between coatings and substrates at 1100℃ and its effects on microstructure stability of the substrates were investigated.A 3-μm-thick substrate diffusion zone(SDZ) layer forms beneath the coating/substrate interface after 5-h heat *** SDZ layer is composed of γ’-Ni_(3) Al phases and needle-like precipitates growing along(100)(110) or(100) ***100-h annealing,the thickness of the SDZ layer increases to~17 μm,much lower than that of the single β-NiAl-coated substrate,while keeping single-crystal microstructure.

关键词： Ni-Al coating EB-PVD Single-crystal superalloy Inter-diffusion Microstructure stability

Corrosion of Duplex Stainless Steel Manufactured by Laser Powder Bed Fusion: A Critical Review

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 587-606页

作者： Yiqi Zhou Decheng Kong Ruixue Li Xing He Chaofang Dong Beijing Advanced Innovation center for materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing100083China Shanghai Key Laboratory of Advanced high-temperature materials and Precision Forming School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai200240China

Laser powder bed fusion (LPBF) is a commonly used additive manufacturing (AM) method for efficiently producing intricate geometric components. This investigation examines factors such as pores, cellular structure, grain size, and inclusions from the manufacturing process that contribute to the corrosion resistance of LPBF DSS. Furthermore, the as-built LPBF duplex stainless steel (DSS) is primarily ferrite due to the rapid cooling process. Therefore, the transformation of ferrite to austenite after various heat treatments in LPBF DSS and its corresponding corrosion resistance are presented. Additionally, a new mixed powder method is proposed to increase the austenite content in the as-built LPBF DSS. This review also focuses on the passivation capability and pitting corrosion performance in LPBF and conventional DSS. This article summarizes the variations in microstructure between as-built and heat-treated LPBF DSS, with their impacts on corrosion resistance, offering insights for manufacturing highly corrosion-resistant LPBF DSS.

关键词： Laser powder bed fusion Duplex stainless steel Microstructure Heat treatment Passivation Pitting corrosion

Lepton number violation in D meson decay

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2015年第1期39卷 7-14页

作者：董海荣冯峰李海波 Institute of high energy Physics Chinese Academy of Sciences center for high energy Physics Peking University

The lepton number violation （LNV） process can be induced by introducing a fourth generation heavy Majorana neutrino, which is coupled to the charged leptons of the Standard Model （SM）. There have been many previous studies on the leptonic number violating decay processes with this mechanism. We follow the trend to study the process： D→Kllπ with the same-sign dilepton final states. We restrict ourselves to certain neutrino mass regions, in which the heavy neutrino could be on-shell and the dominant contribution to the branching fraction comes from the resonance enhanced effect. Applying the narrow width approximation （NWA）, we found that the upper limit for the branching fractions for D^0 → K^- 1＋1＋π- are generally at the order of 10-12 to 10-9, if we take the most stringent upper limit bound currently available in the literature for the mixing matrix elements. We also provide the constraints, which is competitive compared to the LNV B decays, on the mixing matrix element ｜VeN ｜^2 based on the upper limit of D^0→K^-e＋e＋π- estimated from the Monte-Carlo （MC） study at BESⅢ. Although the constraints are worse than the ones from （0vββ） decay in the literature, the future experiment at the charm factory may yield more stringent constraints.

关键词： Majorana neutrino D meson decay lepton number violating mixing matrix element

Geometry of the effective Majorana neutrino mass in the 0νββ decay

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2015年第1期39卷 1-6页

作者：刑志忠周也铃 Institute of high energy Physics Chinese Academy of Sciences center for high energy Physics Peking University

The neutrinoless double-beta （0vββ） decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass （m）ee- We put forward a novel ＇coupling-rod＇ diagram to describe （m）ee in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on （m）ee are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of I（m）eel. It remains usable even if there is a kind of new physics contributing to （m）ee, and it can also be extended to describe the effective Majorana masses （m）eμ, （m）eτ, （m）μμ, （m）,μτ and （m）ττ which may appear in some other lepton-number violating processes.

关键词： Majorana particles neutrino mass 0vββ decay