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First-Principles Study of the Influence of Lattice Misfit on the Behavior and the Ductility Effect of Hafnium in Ni-Ni3AI System

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Acta Metallurgica Sinica(English Letters) 2014年第1期27卷 87-94页

作者： Y. Wu j. Guo W. zhang X. Ma q. zhang j. Hou R. Huang X. Liu Institute of Molecular Engineering and Applied Chemistry Anhui University of Technology Ma'anshan 243002 China Shenyang National Laboratory for Materials Science Instituteof Metal Research Chinese Academy of SciencesShenyang 110016 China College of Physics Science and Technology Shenyang NormalUniversity Huanghe Street 253 Shengyang 110034 China School of Materials Science and Engineering Anhui Universityof Technology Ma'anshan 243002 China

Two Ni/Ni3Al-interface-contained cluster models with/without lattice misfit are studied by first-principles method to clarify the debates about the segregation behaviors of Hafnium （Hf） and explore the influence of lattice misfit on the ductility effect of Hr. It is found that though Hf prefers to substitute A1 rather than Ni in Ni3A1 phase within most of the investigated misfit range, its stronger preferring to Ni phase than NiaA1 phase makes it impossible to go into Ni3A1 phase to occupy A1 site in Ni-Ni3A1 alloys. Bond order analysis in Hf-free case shows that lattice misfit has different effects on the Griffith work of interfacial cleavage 27int/E and the maximum theoretical shear stress Zmax of Ni and Ni3A1, contributing to the existence of anomalous strength-temperature phenomena in NiaA1 alloys. However, the addition of Hf will make the 27int/E （or Zmax） of both Ni3A1 and Ni decrease （or increase） with lattice misfit, indicating that the addition of Hf may make the anomalous strength-temperature relationship in Ni3A1 region disappear locally.

关键词： Hafnium Lattice misfit Segregation Ductility

Synthesis and Characterization of Fe_(50)Cr_(14)Mo_(14)C_(14)B_6Gd_2 Bulk Amorphous Steel

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journal of Materials Science & Technology 2010年第9期26卷 783-786页

作者： M. Iqbal j.I. Akhter H.F. zhang Z.q. Hu Physics Division Pakistan Institute of Nuclear Science &: Technology P.O. Nilore Islamabad Pakistan Shenyang National Laboratory for Materials Science Institute of Metal Research Chinese Academy of SciencesShenyang 110016 China

Bulk amorphous steel having 7 mm thickness was synthesized to evaluate its thermal stability and mechanical *** steel was synthesized by Cu mold casting technique using 1-2N pure *** of the material was done by X-ray diffraction,differential scanning calorimetry and scanning electron *** activation energies were calculated by Kissinger equation and it was found that the steel had better stability against *** properties like Vicker s hardness,nanohardness,elastic modulus and elastic recovery of as-cast and annealed samples were *** was concluded that the present steel had good glass-forming ability（GFA） and mechanical properties.

关键词： Bulk amorphous steels Activation energy Glass-forming ability Mechanical properties

Stability and optoelectronic property of low-dimensional organic tin bromide perovskites

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Chinese Physics B 2021年第3期30卷 483-487页

作者： j H Lei q Tang j He M q Cai School of Science Hunan University of TechnologyZhuzhou 412007China School of Physics and Electronics Science Hunan UniversityChangsha 410082China

The toxicity and degradation of hybrid lead-halide perovskites hinder their extensive *** is thus of great importance to explore non-toxic alternative materials with excellent stability and optoelectronic *** investigate the atomic structures and optoelectronic properties of non-toxic organic tin bromide perovskites(OTBP)with one/zerodimensional(1D/0D)structures by first-principles *** calculated atomic structures show that the 1D/0D OTBPs are stable and the structure of inorganic octahedra in 0D is higher order than that in ***,the origination of exceptional purity emitting light in experiments is explained based on the calculated electronic structure.

关键词： one/zero dimensional non-toxic organic tin bromide perovskites first principle calculation stability Optoelectronic property

A Theoretical Approach for Estimating Fracture Toughness of Ductile Metals

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上海交通大学学报 2004年第z2期38卷 114-119页

作者： Y.T. He F. Li G.q. zhang L.j. Ernst X.j. FU College of Aeronautics University of Air Force Engineering Xi''an 710038 China College of Aeronautics Northwestern Polytechnical University Xi''an710072 China College of Aeronautics University of Air Force Engineering Xi''an 710038 China Philips Centre for Industrial Technology P.O.Box 218 5600 MD Eindhoven The Netherlands Delft University of Technology 2628 CD Delft The Netherlands College of Aeronautics Northwestern Polytechnical University Xi''an 710072 China

Fracture toughness is very important when applying Damage Tolerance Design and Assessment Techniques. The traditional testing approach for obtaining fracture toughness values is costly and time consuming. In order to estimate the fracture toughness of ductile metals, the fracture mechanics theory, materials plastic deformation theory and materials constructive relationships are employed here. A series of formulae and a theoretical approach are presented to calculate fracture toughness values of different materials in the plane stress and plane strain conditions. Compared with test results, evaluated values have a good agreement.

关键词： fracture toughness testing approach evaluated method fracture mechanics theory plastic deformation theory materials constructive relationship theoretical approach

Effects of the Reversely Rotating Assisted Shoulder on Microstructures During the Reverse Dual-rotation Friction Stir Welding

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journal of Materials Science & Technology 2015年第4期31卷 375-383页

作者： j.q.Li H.j.Liu State Key Laboratory of Advanced Welding and joining Harbin Institute of Technology Capital Aerospace Machinery Company

The reverse dual-rotation friction stir welding(RDR-FSW) has the capability to adjust the heat generation because of the separately designed tool shoulder and tool *** welding torque exerted on the workpiece by the reversely rotating shoulder is opposite to that exerted by the rotating tool pin,so the total welding torque is reduced,which is beneficial to reducing the clamping requirement of *** the present paper,a RDR-FSW joint was welded in a condition similar to the optimal welding condition of conventional FSW,and microstructures in various zones were investigated by comparison,aiming to highlight effects of the reversely rotating assisted *** to the heat conduction of the middle cylinder and the bottom end cover on which the assisted shoulder was machined,the thermal effect of RDR-FSW was smaller than that of the conventional ***,the effect of assisted shoulder on the plastic flow or deformation of material or was constrained in a thin layer near the weld top surface,and thus the flow of material especially along the thickness direction was clearly decreased in the *** the heat-affected zone(HAZ),the precipitate coarsening was the main evolution and was completed through the dissolution of small precipitates and the continuous growth of large *** contrast,the dissolution degree of precipitates increased significantly in the thermomechanically affected zone(TMAZ),and a small amount of original meta-stable precipitates transformed to block-shaped stable *** evolutions in the shoulder affected zone(SAZ)and the weld nugget zone were similar,*** majority of original meta-stable precipitates dissolved into the matrix and the remainder transformed to stable precipitates,though the dissolution degree was greater in the *** with the conventional FSW joint,the coarsening degrees of precipitates in the HAZ and TMAZ of RDR-FSW joint were much smaller,as well as the dissolution degrees of p

关键词： Friction stir welding Reverse dual-rotation fricti

Generative Adversarial Network Based Heuristics for Sampling-Based Path Planning

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IEEE/CAA journal of Automatica Sinica 2022年第1期9卷 64-74页

作者： Tianyi zhang jiankun Wang Max q.-H.Meng Department of Electronic and Electrical Engineering Southern University of Science and TechnologyShenzhen 518055China

Sampling-based path planning is a popular methodology for robot path *** a uniform sampling strategy to explore the state space,a feasible path can be found without the complex geometric modeling of the configuration ***,the quality of the initial solution is not guaranteed,and the convergence speed to the optimal solution is *** this paper,we present a novel image-based path planning algorithm to overcome these ***,a generative adversarial network(GAN)is designed to take the environment map(denoted as RGB image)as the input without other preprocessing *** output is also an RGB image where the promising region(where a feasible path probably exists)is *** promising region is utilized as a heuristic to achieve non-uniform sampling for the path *** conduct a number of simulation experiments to validate the effectiveness of the proposed method,and the results demonstrate that our method performs much better in terms of the quality of the initial solution and the convergence speed to the optimal ***,apart from the environments similar to the training set,our method also works well on the environments which are very different from the training set.

关键词： Generative adversarial network(GAN) optimal path planning robot path planning sampling-based path planning

Fault Identification in Power Network Based on Deep Reinforcement Learning

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CSEE journal of Power and Energy Systems 2022年第3期8卷 721-731页

作者： Mengshi Li Huanming zhang Tianyao ji q.H.Wu School of Electric Power Engineering South China University of TechnologyGuangzhou510641China

With the integration of alternative energy and renewables,the issue of stability and resilience of the power network has received considerable *** basic necessity for fault diagnosis and isolation is fault identification and *** conventional intelligent fault identification method needs supervision,manual labelling of characteristics,and requires large amounts of labelled *** enhance the ability of intelligent methods and get rid of the dependence on a large amount of labelled data,a novel fault identification method based on deep reinforcement learning(DRL),which has not received enough attention in the field of fault identification,is investigated in this *** proposed method uses different faults as parameters of the model to expand the scope of fault *** addition,the DRL algorithm can intelligently modify the fault parameters according to the observations obtained from the power network environment,rather than requiring manual and mechanical tuning of *** methodology was tested on the IEEE 14 bus for several scenarios and the performance of the proposed method was compared with that of population-based optimization methods and supervised learning *** obtained results have confirmed the feasibility and effectiveness of the proposed method.

关键词： Artificial intelligence deep q network deep reinforcement learning fault diagnosis fault identification parameter identification power network

Tensile Elastic Behavior of a Zr-Cu-Ag-Al Bulk Metallic Glass

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journal of Materials Science & Technology 2014年第6期30卷 595-598页

作者： q.P.Cao j.B.jin q.Yu X.D.Wang D.X.zhang Y.jiang j.Z.jiang International Center for New-Structured Materials (ICNSM) State Key Laboratory of Silicon MaterialsDepartment of Materials Science and Engineering Zhejiang University Department of Mechanical Engineering University of Nevada Reno NV 89557 USA State Key Laboratory of Modern Optical Instrumentation Zhejiang University

Tensile elastic behavior of bulk Zr46（Cu4.5/5.5Ag1/5.5）46Al8 metallic glass was experimentally investigated. It exhibited linear and non-linear time-independent elastic deformation with a demarcative stress of approximately 500 MPa within the timescale in the present work, and repeated loading-unloading before yielding did not alter stress-strain relationship. The pure linear elastic strain limit is 0.6%, significantly lower than 2% as generally reported, but still much higher than 0.1% observed for typical crystalline alloys. Deviation from linear elastic behavior at stresses higher than 500 MPa is explained here as a macroscopic manifestation of local fluctuations in elastic strain, which becomes pronounced at stresses higher than the critical value. The occurrence of non-linear elasticity is possibly also related to the sinusoidal relationship between shear stress and atomic displacement.

关键词： Bulk metallic glass Tension test Elastic-plastic deformation

THE EFFECTS OF NEGATIVE BIAS AND FLUX RATIO ON THE PROPERTIES OF TiN THIN FILMS FORMED BY FILTERED CATHODIC ARC PLASMA TECHNIqUE

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 369-374页

作者： Y.j.zhang P.X.Yan Z.G.Wu W.W.zhang j.Wang q.j.Xue DeparunentofPhysics LanzhouUniversitryLanzhou730000China DeparunentofPhysics LanzhouUniversitryLanzhou730000China／／StateKeyLaboratoryofSolidLubricationInstituteofChemicalPhysicsTheChineseAcademyofSciencesLanzhou730000China StateKeyLaboratoryofSolidLubrication InstituteofChemicalPhysicsTheChineseAcademyofSciencesLanzhou730000China

The filtered cathodic vacuum-arc (FCVA) technique is a supplementary and alterna tive technique with respect to convendtional physical and chemical vapour deposi tion which can remove macro-particles effectively and make the deposition proces s at ambient temperature. In this work, high quality TiN thin films were deposi ted on silicon substrates at low temperature using the improved filtered cathodi c arc plasma (FCAP) technique. AFM, XRD, TEM were employed to characterize the T iN thin films. The effects of the negative substrate bias on the grain size, pre ferred crystalline orientation, surface roughness of TiN thin films were discuss ed.

关键词： TiN filtered cathodic arc plasma preferred orientation