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PHAsE TRANsFORMATION AND CHARACTERIsTICs IN FRECKLE AREAs FOR INCONEL 625 sUPERALLOY

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Acta Metallurgica sinica(English Letters) 2005年第1期18卷 47-54页

作者： J.x.Dong M.C.Zhang Y.P.Zeng x.s.xie UniversityofscienceandTechnologyBeijing Beijing100083China

The freckle formation and their phase characterizatics in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in an Inconel 625 allay. These results show that in freckle areas a large number of M6C, MC, Laves and δ phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and Nb during solidification, which results in almost of these freckle areas covered by these complex precipitated phases and induces small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give a reasonable interpretation of the freckle feature for this alloy.

关键词： freckle superalloy Inconel 625 thermodynamic calculation

CREEP CRACK GROWTH BEHAVIOR OF ALLOY 718 DURING HIGH TEMPERATURE ExPOsURE

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Acta Metallurgica sinica(English Letters) 2005年第2期18卷 164-172页

作者： J.x.Dong M.C.Zhang Y.P.Zeng x.s.xie DepartmentofMaterialscience UniversityofScienceandTechnologyBeijingBeijing100083China

Alloy 718 is a precipitation strengthened nickel-based superalloy based on the precipitation of γ″-Ni3Nb (DO22 structure) and γ′-Ni3(Al,Ti) (L12 structure) phases. Creep crack growth rate (CCGR) was investigated after high temperature exposure at 593, 650 and 677℃ for 2000h in Alloy 718. In addition to the coalescence of γ′/ γ″ and the amount increasing of δ phase, the existence of a bcc chromium enriched α-Cr phase was observed by sEM, and the weight fraction of α-Cr and other phases were determined by chemical phase analysis methods. The CCGR behavior and regulation have been analyzed by means of strength and structure analysis approaches. The experimental results show higher the exposure temperature and longer the exposure time, lower the CCGR. This is probably attributed to the interaction of material softening and brittling due to complex structure changes during high temperature exposure. Therefore, despite α-Cr phase formation and amount enhancement were run in this test range. It seems to us a small amount of α-Cr will be not harmful for creep crack propagation resistance, which is critical for disk application in aircraft and land-based gas turbine.

关键词： Alloy 718 creep crack growth rate α-Cr phase

FRECKLE FORMATION AND CHARACTERIZATION OF A Ni-Cr-Mo-Fe-W ALLOY

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Acta Metallurgica sinica(English Letters) 2004年第4期17卷 414-418页

作者： J.x.Dong M.C.Zhang Y.P.Zeng x.s.xie University of science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 ChinaUniversity of Science and Technology Beijing Beijing 100083 China

The freckle formation and their phase characterization in freckle areas were investigated by means of microstructure analysis approaches and a thermodynamic equilibrium phase calculation method in a Ni-Cr-Mo-Fe-W alloy. These results show that in freckle areas a large number of M6C, μ and P phases precipitate in grain boundaries even within grain due to the enrichment and segregation of Mo and C during solidification, which results in small grains in freckle areas. Equilibrium phase and liquid segregation calculation can give an reasonable interpretation of the freckle feature for this alloy.

关键词： freckle Ni-Cr-Mo-Fe- W alloy thermodynamic calculation

THE sEGREGATION OF sULFUR AND PHOsPHORUs IN NICKEL-BAsE ALLOY 718

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Acta Metallurgica sinica(English Letters) 1997年第6期10卷 510-514页

作者： J.x. Dong x.B. Liu x.s. xie and R.G. Thompson(Department of Materials science and Engineering, University of science and Technology Beijing, Beijing 100083, China)(University of Alabama at Birmingham, Birmingham AL35294-4461, UsA) Univ of science and Technology Beijing Beijing China

The segregation behavior of sulfur and phosphorus has been studied by means of scanning Auger microprobe (sAM) on microstructural interfaces,such as grain boundaries and carbide/matrix interfaces,The experimental results clearly reveal that sulfur strongly segregates on carbide/matrix interfaces,while phosphorus predominantly distributes on grain boundaries. Molybdenum tends to segregat on grain boundaries.

关键词： superalloy segregation,Alloy 718

Multibeam Raman amplification of a finite-duration seed in a short distance

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Chinese Physics B 2021年第10期30卷 428-435页

作者： Y G Chen Y Chen s x xie N Peng J Q Yu C Z xiao Key Laboratory for Micro-/Nano-Optoelectronic Devices of Ministry of Education School of Physics and ElectronicsHunan UniversityChangsha 410082China Collaborative Innovation Center of IFsA(CICIFsA) Shanghai Jiao Tong UniversityShanghai 200240China

A new scheme of multibeam Raman amplification(MRA)is proposed in virtue of the collective mode by sharing a common scattered *** laser beams can provide a higher growth rate,but the overlapping region limits the amplification *** suggest to use a finite-duration seed to facilitate MRA in a short *** two-dimensional particle-in-cell simulations,we find that two-beam Raman amplification has a much higher growth rate than that of singlebeam *** growth rate depends on the initial seed amplitude,electron temperature,and seed *** empirical criterion,γ0τc=1,whereγ0 is the theoretical growth rate of MRA,is used to choose a proper duration for a higher growth *** a total amplification length of 320µm,the two-beam Raman amplification shows nonlinear features of pulse compression and a bow-shape wave front,indicating that the amplification has finally entered the self-similar regime.

关键词： multibeam Raman amplification growth rate finite-duration

Dissipationless layertronics in axion insulator MnBi2Te4

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National science Review 2024年第6期11卷 189-196页

作者： shuai Li Ming Gong shuguang Cheng Hua Jiang x.C.xie school of Physical science and Technology Soochow University Institute for Advanced study Soochow University International Center for Quantum Materials School of Physics Peking University Department of Physics Northwest University Interdisciplinary Center for Theoretical Physics and Information sciences Fudan University Hefei National Laboratory

surface electrons in axion insulators are endowed with a topological layer degree of freedom followed by exotic transport phenomena, e.g., the layer Hall effect. Here, we propose that such a layer degree of freedom can be manipulated in a dissipationless way based on the antiferromagnetic MnBi2Te4with tailored domain structure. This makes MnBi2Te4a versatile platform to exploit the ‘layertronics’ to encode, process and store information. Importantly, the layer filter, layer valve and layer reverser devices can be achieved using the layer-locked chiral domain wall modes. The dissipationless nature of the domain wall modes makes the performance of the layertronic devices superior to those in spintronics and valleytronics. specifically, the layer reverser, a layer version of the Datta–Das transistor, also fills up the blank in designing the valley reverser in valleytronics. Our work sheds light on constructing new generation electronic devices with high performance and low-energy consumption in the framework of layertronics.

关键词： axion insulator MnBi2Te4 layertronics antiferromagnetic domain wall dissipationless transport

The preface: Interplay of topological and magnetic orders in the Mn-Bi-Te family

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National science Review 2024年第2期11卷 6-7页

作者： Fu-Chun Zhang Hai-Zhou Lu x.C.xie Kavli Institute for Theoretical sciences University of Chinese Academy of Sciences Department of Physics Southern University of Science and Technology (SUSTech) International Center for Quantum Materials School of Physics Peking University

The discovery and synthesis of MnBi2Te4in 2013 initially garnered little attention [1]. Yet, the revelation of its topological properties in 2019 [2–6] sparked a surge of research into the MnBiTe family. These extensive studies are primarily driven by two objectives:the realization of a high-temperature quantum anomalous Hall effect （QAHE） and the exploration of exotic phases born from the interplay of topological and magnetic orders,

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Progress on the antiferromagnetic topological insulator MnBi2Te4

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National science Review 2024年第2期11卷 33-49页

作者： shuai Li Tianyu Liu Chang Liu Yayu Wang Hai-Zhou Lu x.C.xie Department of Physics Harbin Institute of Technology shenzhen Institute for Quantum science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) Quantum science Center of Guangdong-Hong Kong-Macao Greater Bay Area(Guangdong) shenzhen Key Laboratory of Quantum science and Engineering International Quantum Academy Beijing Academy of Quantum Information sciences Beijing Key Laboratory of Optoelectronic Functional Materials&Micro-Nano Devices Department of Physics Renmin University of China state Key Laboratory of Low Dimensional Quantum Physics Department of PhysicsTsinghua University Frontier science Center for Quantum Information Hefei National Laboratory International Center for Quantum Materials School of Physics Peking University Institute for Nanoelectronic Devices and Quantum Computing Fudan University

Topological materials, which feature robust surface and/or edge states, have now been a research focus in condensed maTher physics. They represent a new class of materials exhibiting nontrivial topological phases,and provide a platform for exploring exotic transport phenomena, such as the quantum anomalous Hall effect and the quantum spin Hall effect. Recently, magnetic topological materials have attracted considerable interests due to the possibility to study the interplay between topological and magnetic *** particular, the quantum anomalous Hall and axion insulator phases can be realized in topological insulators with magnetic order. MnBi2Te4, as the first intrinsic antiferromagnetic topological insulator discovered, allows the examination of existing theoretical predictions; it has been extensively studied, and many new discoveries have been made. Here we review the progress made on MnBi2Te4from both experimental and theoretical aspects. The bulk crystal and magnetic structures are surveyed first, followed by a review of theoretical calculations and experimental probes on the band structure and surface states, and a discussion of various exotic phases that can be realized in MnBi2Te4. The properties of MnBi2Te4thin films and the corresponding transport studies are then reviewed, with an emphasis on the edge state transport. Possible future research directions in this field are also discussed.

关键词： MnBi2Te4 magnetic topological insulator antiferromagnetic quantum anomalous Hall effect axion insulator

HIGH TEMPERATURE CRACK PROPAGATION AND FRACTURE OF sUPERALLOYs

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Acta Metallurgica sinica(English Letters) 1999年第1期12卷 54-61页

作者： x.s. xie, Z.C. xu and J.x. Dong High Temperature Materials Research Laboratory,University of science and Technology Beijing,Beijing 100083, China

High temperature crack propagation and fracture behavior of disks produced by six superalloys have been studied. Crack propagation rates were determined at 650 creep, fatigue and creep/fatigue interaction conditions. The crack propagation rate is raised with increasing strength of superalloy and is also increased with the dwelling time at maximum stress level of cyclic creep test condition. Crack propagation behavior is closely related to high temperature ductility (such as creep strain and stress rupture elongation). Ductility improvement can increase crack propagation resistance by means of softening heat treatment, controlling grain boundary precipitate and microalloying treatment (such as Mg addition to superalloy). \=

关键词： crack propagation fracture superalloy magnesium