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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

STUDY ON THE SURFACE MODIFICATION OF NANOMETER CARBON PARTICLES IN ATMOSPHERIC PLASMA

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Acta Metallurgica Sinica(English Letters) 2002年第2期15卷 177-181页

作者： Y.J. ge, g.q. zhang, Y.M. Liu, X.g. guo and Z.F. Zhao Beijing Institute of Printing, Beijing 102600, China Beijing Institute of Printing Beijing 102600China

The surface modification of nanometer carbon material has been studied by using an Induced Dielectric Barrier Discharge Plasma device (IDBD). The experimental results show that with different work gases and different discharge conditions, the surface behaviors of carbon black can be changed according to needs, including the use of different functional groups and the change of the surface roughness of carbon particles etc., which increased the grinding and dispersion abilities in binder.

关键词： surface modification. nanometer material IDBD plasma. carbon black

Progress in Understanding Color Maintenance in Solid-State Lighting Systems

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Engineering 2015年第2期1卷 170-178页

作者： Maryam Yazdan Mehr Willem Dirk van Driel g.q.(Kouchi) zhang Delft University of Technology Material Innovation Institute (M2i)

In this paper, progresses of color maintenance, also known as color shift, in solid-state lighting(SSL) systems are thoroughly reviewed. First, color shift is introduced and a few examples are given from different real-life industrial conditions. Different degradation mechanisms in different parts of the system are also explained. Different materials used as lenses/encapsulants in light-emitting diode(LED)-based products are introduced and their contributions to color shift are discussed. Efforts put into standardization, characterizing, and predicting lumen maintenance are also briefly reviewed in this paper.

关键词： light-emitting diode (LED) color shift lumen depreciation lumen degradation

Characterization of Interface Strength as Function of Temperature and Moisture Conditions

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电子与封装 2007年第2期7卷 16-22页

作者： W.D. van Driel P.J.J.H.A. Habets M.A.J. van gils g.q. zhang Philips Semiconductors 6500 MD Nijmegen The Netherlands Philips Applied Technologies 5600 MD Eindhoven The Netherlands Delft University of Technology Mekelweg 2 2628 CD Delft The Netherlands Eindhoven University of Technology Eindhoven The Netherlands

Since Moisture Sensitivity Level (MSL) tests are part of the international reliability qualification standards, all the microelectronics components/products have to pass these specifications. Therefore, it is important to be able to efficiently and accurately characterize and predict the moisture related material and interface behavior in the real manufacturing, processing, testing and application conditions. The success of interfacial fracture mechanics approach to analyze moisture-induced failures in IC packaging strongly depend on accurate characterization of the critical adhesion strength, gc. However, its measurement is complicated by the fact that adhesion depends not only on moisture concentration, C, but also temperature, T, and mode mixity, ψ. This paper described our research to develop a reliable methodology for interface toughness evaluation as function of temperature, humidity and mode mixity. Our methodology includes using the four-point bending test and shaft-loaded-blister method. Dedicated specimens consisting of various types of moulding compounds bonded onto leadframe are manufactured. Besides temperature, moisture content and mode mixity effects, also the influences of surface treatment (leadframe oxidation and contamination) and production process on the interface fracture toughness are evaluated. Multi-physics-based numerical methods are used to transfer the experimental critical loads to an interface strength parameter. These analysis covers mechanical, moisture diffusion, vapor pressure, hygro-swelling and CTE-mismatch modeling. To test and improve the methodology, various effects are evaluated, such as crack-length dependency, material properties, specimen- width, displacement-rate of the upper support/shaft, etc. The results of the proposed methodology indicate, as expected, a change in interface toughness by mode mixity, moisture content and temperature. It is found that gc decreases with increasing moisture content and temperature. The pr

关键词：封装散热温度功能

Molecurar Breeding for Resistant Varieties Against Asian Rice gall Midge in China

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分子植物育种 2007年第2期5卷 228-231页

作者： B.C. Huang　 Y. zhang　 Z.W. Xie　 g.q. zhang　 H.X. Xiao　 H. Li　 C.F. Huang　 M.Z. Liu　 S.C.Zhou　 S. Katiyar 　J. Bennett Plant Protection Research Institute Guangdong Academy of Agricultural Sciences Guaugzhou 510640 China Rice Research Institute Guaugdong Academy of Agricultural Sciences Guaugzhou 510640 China South China Agricultural Uuiversty Guaugzhou 510642 China Rice Research Institute of Ningdu County Jiengxi 342818 China Department of Biotechnology Indira Gandhi Agricultural University Raipu 492006 （C.G） India Division of Plant Breeding Genetics and Biotechnology International Rice Research Instituti DAPO 7777 Metro Manila Phillipines

Asian rice gall midge (gM) is a major rice pest in South China. Breeding resistance varieties has been a viable and ecologically acceptable approach for managing the pest. This paper reports that the progress of

关键词：品种育种技术稻子亚洲中国

用于后端工艺中铜/低k材料金属去除的实验数值研究(英文)

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电子工业专用设备 2006年第9期35卷 51-58页

作者： R. Kregting O. van der Sluis R.A.B. Engelen W.D. van Driel g.q. zhang Philips Applied Technologies Eindhoven The Netherlands Philips Semiconductors Eindhoven TheNetherlands PME/Delft University of Technology Delft The Netherlands

Wire pull tests are generally conducted to assess the wire bonding.q.ality. Using Cu/low-k technology, two failure modes are usually observed: Failure in the neck of the wire (neck break) and metal peel off (MPO). The objective of our study is to investigate the root cause of metal peel off by using a combined experimental and numerical approach. First, dedicated failure analyses are conducted to identify the failure locations. Scanning Electron Microscopy analysis for a large number of completely failed samples shows that the delaminated interface, after MPO has occurred, is always the interface on top of the third metal layer, near the centre of the stack. However, these inspections do not indicate where and when MPO initiated. To understand the initiation, incremental (non-destructive) wire pull tests are used. These samples have not failed completely, but may already show the initiating crack in either of the two possible regions. Combined with use of scanning acoustic tomography (SCAT) and focused ion beam (FIB) show that MPO initiates by delamination in the back-end structure at the interface on top of the third metal layer. Secondly, a 3D FEM model for a half bond pad with partial wire bond is used to simulate the wire pull test, in order to understand the failure mode. Analyses using stress as a failure index indicates, however, that the top interface is the most critical one. This does not match with the experimental observation. Therefore, an alternative, energy-based failure index is used, the so-called area release energy method (ARE). The ARE method approximately identifies the same critical interface as found from experiments. It is assumed that the presence of a stiff layer nearby a potential crack location restricts the elastic deformation upon release. This indicates that the initiation of a crack in the upper and lower interfaces results in the release of a lower amount of energy when compared to an interface in the centre, where the surrounding ma

关键词： mode Figure MPO ARE

Effect of a High Magnetic Field on the Shape of the γ' Precipitates in Cast Nickel-based Superalloy K52

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Journal of Materials Science & Technology 2009年第3期25卷 379-382页

作者： X. Ren g.q. Chen W.L. Zhou C.W. Wu C. Yuan J.S. zhang State Key Laboratory of Materials Modification by Laser Ion and Electron Beams Dalian University of Technology Dalian 116085 China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology Dalian 116085 China Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China

The shape change of the γ＇ precipitates of cast Ni-based superalloy K52 after aging treatment under a high magnetic field was investigated. The results show that duplex γ＇ precipitates are present in the γ matrix after aging treatment with or without the magnetic field. One is the coarse particles with average size of 500 nm; the other is fine spherical γ＇ precipitates with average of 100 nm in diameter. The application of a 10T magnetic field only results in the shape of the coarse γ＇ particles changing from spherical to cuboidal when the alloys subjected to the same heat treatments. This shape change was mainly discussed based on the strain energy increase caused by the difference in magnetostriction between the γ matrix and γ＇ precipitates. The fine γ＇ particles still keep spherical. Further TEM observations shows that a number of γ particles in nano-scale precipitate in the coarse γ＇ particles in the specimens treated without the magnetic field. In addition, it was found that the magnetic field caused the decrease of the hardness in the alloy, and the hardness was associated with the field direction.

关键词： Ni-based superalloy High magnetic field Magnetostrictive strain energy Precipitation

RESEARCH AND DEVELOPMENT OF HIgH TEMPERATURESTRUCTURAL MATERIALS FOR AERO-ENgINE APPLICATIONS

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Acta Metallurgica Sinica(English Letters) 2005年第4期18卷 443-452页

作者： g. q. zhang Beijing Institute of Aeronautical Materials （BIAM） Beijing 100095 China

The status of research, development of superalloys and materials processing ＆ fabrication technologies for aero-engine applications in China Aviation Industry, with an emphasis on recent achievements at BIAM including directionally solidified and single crystal superalloys for blade and vane applications, wrought superqlloys for aero-engine disks and rings, and powder metalurgy （PM） superalloys for high performance disk applications were described. It was also reviewed the development of new class of high temperature structural materials, such as structural intermetallics, and advanced material processing technologies including rapid solidification, spray forming and so on. The trends of research and development of the above mentioned superalloys and processing technologies are outlined. Cast, wrought and PM superalloys are the workhorse materials for the hot section of current aero-engines. New high temperature materials and advanced processing technologies have been and will be the subject of study. It is speculated that high performance, high purity and low cost superalloys and technologies will play key roles in aero-engines.

关键词： superalloy intermetallic materials processing aero-engine application

Catalyst–Support Interaction in Polyaniline‑Supported Ni_(3)Fe Oxide to Boost Oxygen Evolution Activities for Rechargeable Zn‑Air Batteries

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Nano-Micro Letters 2025年第1期17卷 176-190页

作者： Xiaohong Zou qian Lu Mingcong Tang Jie Wu Kouer zhang Wenzhi Li Yunxia Hu Xiaomin Xu Xiao zhang Zongping Shao Liang An Department of Mechanical Engineering The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment TechnologySchool of Environmental Science and TechnologyNanjing University of Information Science and TechnologyNanjing 210044People’s Republic of China Department of Chemistry The Chinese University of Hong KongMa Lin BuildingShatinHong Kong SAR 999077People’s Republic of China WA School of Mines:Minerals Energy and Chemical Engineering(WASM‑MECE)Curtin UniversityPerthWA 6102Australia Research Institute for Advanced Manufacturing The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China Research Institute for Smart Energy The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong SARPeople’s Republic of China

Catalyst–support interaction plays a crucial role in improving the catalytic activity of oxygen evolution reaction(OER).Here we modulate the catalyst–support interaction in polyaniline-supported Ni_(3)Fe oxide(Ni_(3)Fe oxide/PANI)with a robust hetero-interface,which significantly improves oxygen evolution activities with an overpotential of 270 mV at 10 mA cm^(-2)and specific activity of 2.08 mA cm_(ECSA)^(-2)at overpotential of 300 mV,3.84-fold that of Ni_(3)Fe *** is revealed that the catalyst–support interaction between Ni_(3)Fe oxide and PANI support enhances the Ni–O covalency via the interfacial Ni–N bond,thus promoting the charge and mass transfer on Ni_(3)Fe *** the excellent activity and stability,rechargeable Zn-air batteries with optimum Ni_(3)Fe oxide/PANI are assembled,delivering a low charge voltage of 1.95 V to cycle for 400 h at 10 mA cm^(-2).The regulation of the effect of catalyst–support interaction on catalytic activity provides new possibilities for the future design of highly efficient OER catalysts.

关键词： Catalyst-support interaction Supported catalysts Heterointerface Oxygen evolution reaction Zn-air batteries