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Journal of Wuhan University of Technology(Materials Science) 2008年第1期23卷 89-94页

作者：黄开金 LIN Xin XIE Changsheng T M Yue State Key Laboratory of Plastic Forming Simulation and Mould Technology Huazhong University of Science and Technology Wuhan 430074 China State Key Laboratory of Solidification Processing Northwestern Polytechnic University Xi＇an 710072 China Department of Industrial and Systems Engineering Hong Kong Polytechnic University Hung Hom Hong Kong China

Wear-resistant laser-induced thermite reaction Al2O3 ceramic coatings can be fabricated on pure Al and AA7075 aluminum alloy by laser cladding （one-step method） and laser cladding followed by laser re-melting （two-step method） using mixed powders CuO-Al-SiO2 in order to improve the wear properties of aluminum and aluminum alloy, respectively. The microstructure of the coatings was characterized by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The wear resistance of the coatings was evaluated under dry sliding wear test condition at room temperature. Owing to the presence of hard α-Al2O3 and γ-Al2O3 phases, the coatings exhibited excellent wear resistance. In addition, the wear resistance of the coatings fabricated by two-step method is superior to that of the coatings fabricated by one-step method.

关键词： laser cladding thermite reaction aluminum alloy wear

Anisotropy of Fatigue Behavior and Tensile Behavior of 5A06 aluminum alloy Based on Infrared Thermography

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Journal of Wuhan University of Technology(Materials Science) 2017年第1期32卷 155-161页

作者：闫志峰张红霞 CHEN Pengda WANG Wenxian Shanxi Key Laboratory of Advanced Magnesium-Based Materials Taiyuan University of Technology030024 TaiyuanChina School of Materials Science and Engineering Taiyuan University of TeehnologyTaiyuan 030024China

The fatigue behavior during high cycle fatigue testing and the tensile behavior of 5A06 aluminum alloy considering the anisotropy were *** types of specimens including longitudinal specimen（parallel to the rolling direction） and transverse specimen（perpendicular to the rolling direction） were *** thermography was employed to monitor the temperature evolution during the fatigue and tensile *** temperature evolution curves in the two directions were contrastively *** is found that the temperature evolution during fatigue process possesses four stages：initial temperature rise stage,slow temperature decline stage,rapid temperature rise stage,and finial temperature decline *** heat generating mechanisms of the four stages are *** differences can be found between the longitudinal specimen and transverse specimen in fatigue strength and fatigue *** fatigue strength and fatigue life of longitudinal specimen are higher than those of transverse *** the tensile and fatigue testing process,the fracture temperature in the transverse direction are higher than that in the longitudinal *** fatigue strength prediction by means of infrared thermography has a good consistency with that by the traditional method.

关键词： aluminum alloy anisotropy fatigue strength infrared thermography

Numerical modeling of annular electromagnetic stirring with intercooling in direct chill casting of 7005 aluminum alloy billet

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Progress in Natural Science:Materials International 2019年第1期29卷 81-87页

作者： Yajun Luo Zhifeng Zhang Department of Mechanical Engineering Hunan Institute of Engineering General Research Institute for Non-Ferrous Metals Hunan Provincial Key Laboratory of Vehicle Power and Transmission System Hunan Institute of Engineering

Uniform direct chill(UDC) casting method was developed by combining annular electromagnetic stirring(AEMS) with intercooling in direct chill casting. In order to investigate effect of UDC on flow patterns, temperature profiles and solidification during the casting, a numerical model of the UDC casting process was developed and used to simulate the UDC casting process for preparing 7005 aluminum alloy billets. The comparison of the calculated results of UDC casting with normal direct chill(NDC) casting indicated that flow patterns, temperature profiles and the sump depth are modified remarkably by the application of annular electromagnetic stirring and intercooling during the direct chill casting. The sump profile and the temperature history during UDC casing were studied, and the mechanism of the casting process were discussed. The comparisons between the simulations and experimental results suggested that the proposed model provides good agreement for the sump profiles and the temperature history within the billets.

关键词： aluminum alloy Direct chill casting Simulation Electromagnetic stirring Intercooling

Corrosion resistance of a silane/ceria modified Mg-Al-layered double hydroxide on AA5005 aluminum alloy

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Frontiers of Materials Science 2019年第4期13卷 420-430页

作者： Wei WU Fen ZHANG Yu-Chao LI Yong-Feng ZHOU Qing-Song YAO Liang SONG Rong-Chang ZENC Sie Chin TJONG Dong-Chu CHEN College of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China School of Materials Science and Engineering Liaocheng UniversityLiaocheng 252059China School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450002China Department of Physics City University of Hong KongTat Chee AvenueHong KongChina School of Materials Science and Energy Engineering Foshan UniversityFoshan 528000China

The present work aimed at assessing the electrochemical behavior and the corrosion inhibition performance of Mg-Al-layered double hydroxide(LDH)coatings modified with methyltrimethoxysilane(MTMS)and cerium nitrate on AA5005 aluminum *** chemical compositions and surface morphologies of the coatings were investigated by XRD,FT-IR and FE-SEM,while their corrosion resistance was evaluated by electrochemical and immersion *** optimum corrosion resistance of the composite coatings was obtained by adding 10^−2 mol·L^−1 cerium *** excess addition of cerium nitrate resulted in a loose structure and poor corrosion resistance of the *** corrosion mechanism of the composite coatings was proposed and discussed.

关键词： aluminum alloy layered double hydroxide polymer coating cerium oxide corrosion resistance

Study on wear behavior of plasma electrolytic oxidation coatings on aluminum alloy

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Rare Metals 2006年第Z2期25卷 141-145页

作者： KANG Suk-Bong LEE Jung-Moo Department of Materials Engineering Korean Institute of Machinery & Materials Gyeongnam 641831 Korea

Thick and hard ceramic coatings were fabricated on A356 aluminum alloy by using plasma electrolytic oxidation(PEO) technique. The microstructure and phase composition of the PEO coatings were examined by using SEM and XRD method. It is found that the PEO coatings are mainly composed of crystalline α-Al2O3 and mullite. The dry sliding wear test of PEO coatings were carried out on a ring-on-ring wear machine. Results shows that there is hardly no wear loss of polished PEO coatings while the wear rate of uncoated aluminum alloy is 4.3×10-5 mm3·(N·m)-1 at a speed of 0.52 m·s-1 and a load of 40 N.

关键词： aluminum alloy plasma electrolytic oxidation ceramic coating wear

Influence of Mechanical Behavior between the Grains on Stress Fluctuation of aluminum alloy Thick Plate

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Journal of Wuhan University of Technology(Materials Science) 2013年第6期28卷 1212-1216页

作者： LIAO Kai WU Yunxin GONG Hai School of Mechanical and Electrical Engineering Central South University of Forestry and Technology Guilin University of Electrical Technology School of Mechanical and Electrical Engineering Central South University

The research on fluctuation and inhomogeneity of internal stress of aluminum alloy thick plate is theoretical and technological base for stress control technology. By using X-ray diffraction technique and mechanical test method, aluminum alloy with typical fine sub-grains, coarse recrystallized grains, and second phase was analyzed; the interactive mechanical model between grains was built for analysis of variation of internal stress within the local micro structure by imitating the actual distribution of grains. The experimental result shows that the mechanical model can effectively explain the reason for fluctuation of microscopic stress, which also proves that the inhomogeneous distribution of metal organization is the cause for the complex distribution of microscopic stress. The model can well describe stress distribution of thick plate caused by thermal deformation. Besides, it well describes mechanism of stress fluctuation.

关键词： aluminum alloy stress fluctuation internal stress plastic deformation

Effect of void nucleation on microstructure and stress state in aluminum alloy tailor-welded blank

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Progress in Natural Science:Materials International 2021年第1期31卷 77-85页

作者： L.Xing M.Zhan P.F.Gao M.Li Y.D.Dong T.Y.Wang State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment Key Laboratory of High Performance Manufacturing for Aero Engine (Northwestern Polytechnical University) Ministry of Industry and Information Technology

The microscopic damage initiation characteristic in welded joint greatly determines the subsequent damage evolution and fracture behavior of aluminum alloy tailor-welded blank(TWB) during plastic forming. In this study, the interactive dependence of void nucleation on microstructure and stress state in the welded joint of a2219 aluminum alloy TWB was quantitatively explored by in-situ SEM testing. Moreover, a micromechanical model based on actual microstructure was adopted to reveal the underlying mechanisms from the perspective of microscopic heterogeneous deformation. The results showed that three void nucleation mechanisms, including particle-cracking, interface-debonding and matrix-cracking, coexisted in the deformation at different microstructure regions and stress states. The nucleation strain of each mechanism mainly depended on the particle volume fraction, grain size and stress triaxiality. Besides, the proportions of particle-cracking and interfacedebonding greatly varied with the grain size and particle volume fraction, and the variation law changed with the stress state. The proportion of matrix-cracking had a weak dependence on the microstructure, while increased with the stress triaxiality decreasing. It made the damage initiation in aluminum alloy welded joint transit from particle-cracking dominance to matrix-cracking dominance with the stress triaxiality *** micromechanical modeling results suggested that the changes of evolutions and distributions of Mises stress in particle, hydrostatic stress at interface and plastic strain in matrix with microstructure and stress state were responsible for the above effects.

关键词： aluminum alloy Welded joint Void nucleation Microstructure Stress state Micromechanical model

Fabrication of Superhydrophobic Surface with Different Metal Films on aluminum alloy

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Chemical Research in Chinese Universities 2016年第2期32卷 155-158页

作者： WANG Yang LIU Xiaowei ZHANG Haifeng ZHOU Zhiping Department of Microelectronics Harbin Institute of Technology Harbin 150001 P. R. China

A simple technique was developed for the fabrication of a superhydrophobic surface on the aluminum alloy sheets. Different hierarchical structures（Ag, Co, Ni and Zn） were formed on the aluminum surface by the galvanic replacement reactions. After the chemical modification of them with fluorination, the wettability of the surfaces was changed from superhydrophilicity to superhydrophobicity. Scanning electron microscopy（SEM）, energy dispersive spectrometry（EDS） and water contact angle measurement were performed to characterize the morphologi- cal characteristic, chemical composition and superhydrophobicity of the surfaces. The as-prepared superhydrophobic surfaces showed a water contact angle as high as ca.160° and sliding angle as low as ca.3°. We hope the method to produce superhydrophobic surface can be used in many fields.

关键词： Superhydrophobicity Water contact angle aluminum alloy Micro-nano structure

Correlation Between Microhardness and Microstructure of Anodic Film on 2024 aluminum alloy

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Journal of Wuhan University of Technology(Materials Science) 2015年第3期30卷 586-590页

作者：张培 ZUO Yu 赵旭辉 TANG Yuming ZHANG Xiaofeng Beijing Key Laboratory of Electrochemical Process and Technology for Materials College of Materials Science and Engineering Beijing University of Chemical Technology Guangxi Key Laboratory of Farm Products Processing (Cultivation Base) College of Chemistry and Material Yulin Normal University

The correlation between the microhardness and microstructure features of anodic films on 2024 aluminum alloy formed in the mixed sulfuric acid/oxalic acid electrolyte was studied using micro-hardness tester and scanning electron microscope （SEIVI）. The results show that the microhardness of the anodic film is influenced by the mierostructure of the anodic film such as the film porosity, and the order and continuity of the hexagon columnar ceils. The film microhardness increases as the porosity of the anodic film decreases and the order and continuity of the film ceils increase. With the same current density, as the anodic film thickens with anodizing time, the film microhardness increases because the film porosity decreases and the order and continuity of the cells are also improved. Under the condition of the same anodizing time, as the current density increases, the film microhardness decreases due to the higher film porosity and the poorer order and continuity of the film ceils. The film porosity increases because the increased current density can accelerate the oxidation reaction, strengthen the filed-assisted dissolution and the heating effect in the anodic film, resulting in decreased film order and continuity.

关键词： aluminum alloy anodizing microhardness porosity microstructure

Discharge Characteristic of Micro-Arc Oxidation on aluminum alloy under the Changing Electrolyte Temperature

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Journal of Materials Science and Chemical Engineering 2022年第11期10卷 24-35页

作者： Hongwei Yang Xin Wang Zongtao Zhu Ruilin Liu CRRC Nanjing Puzhen Co. Ltd. Nanjing China School of Materials Science & Engineering Southwest Jiaotong University Chengdu China

The electrolyte temperature has a great influence on the performance of the coating prepared by micro-arc oxidation (MAO). The behavior of MAO discharge in the changing electrolyte temperature has been investigated. Compared to constant electrolyte temperature in conventional MAO process, the process has different discharge characteristics under the changing electrolyte temperature. The amplitude of pulse voltage was detected to study the change of discharge characteristic under the constant-current control of MAO power supply. Three successive discharge stages were differentiated by the variable the pulse voltage versus process time. Since there were significant changes in the sound, the sound signals were acquired and the audio analysis was used to describe the changing of the MAO discharge at different stages. Optical emission spectroscopy (OES) was employed in situ to unveil how the micro-discharge changed with the temperature increasing. Scanning electron microscopy (SEM) was used to characterize the morphology of the coatings on 6N01 aluminum alloy prepared by normal process with the constant-temperature control of the MAO electrolyte and by the process under the changing electrolyte temperature. A mode of film growth and micro-discharge was given to describe the effects of the changing electrolyte temperature in the whole MAO process.

关键词： Micro-arc Oxidation aluminum alloy Discharge Characteristics Electrolyte Temperature