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Effect of DH treatment on microstructure and mechanical properties of an LM28-0.3wt.%Nd hypereutectic aluminum silicon alloy

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Rare Metals 2007年第6期26卷 578-583页

作者： GAO Bo chen Lei YU fuxiao SUN Shuchen TU Ganfeng School of Materials and Metallurgy Northeastern University Shenyang 110004 China

In this article, a novel heat treatment method, deformation heat （DH） treatment （extrusion ＋ aging）, was employed on a hypereutectic aluminum silicon alloy （LM28-0.3wt.%Nd）, and its effect on microstructure and mechanical properties of this alloy was investigated. It can be concluded that the eutectic microstructure disappears after the DH treatment, in the meantime the morphology of α（Al） solid solution was transformed from fir-troe and cellular to equiaxed, Si was refined with grain sizes of about 1-10 μn and distributed dispersedly, even some of them became globular shape, which can reduce stress accumulation effectively. Mechanical properties test indicated that the DH treatment could significantly improve the room-ternperature strength and have little effect on the high-temperature strength of LM28-0.3wt.%Nd alloy. The fracture mechanism is ductile fracture by fracture morphology analysis.

关键词： Al-Si alloys Nd deformation heat treatment mechanical properties

Influence of stress on the creep behavior of Cu particle enhancement SnPb based composite solder joints

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Rare Metals 2007年第1期26卷 51-55页

作者： YAN Yanfu YAN Hongxing chen fuxiao ZHANG Keke ZHU Jinhong School of Materials Science and Engineering Henan University of Science and Technology Luoyang 471003 China

Lap joints with a 1 mm^2 cross-sectional area were fabricated using Cu particle enhancemem 63Sn37Pb based composite solder and 63Sn37Pb eutectic solder to examine the influence of stress on the creep behavior of the solder joints. The results indicate that the creep resistance of the composite solder joints is generally superior to that of the conventional 63Sn37Pb solder joints. At the same time, the creep rupture life of the composite solder joints is declined with increasing stress and drops faster than that of the 63Sn37Pb eutectic solder joints.

关键词： composite solder stress creep rupture life particle-enhancement 63Sn37Pb

Inhibiting plastic tensile instability of non-symmetric thin-walled shell component via increasing regional metal inflow based on heterogeneous pressure-carrying medium

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Chinese Journal of Aeronautics 2024年第1期37卷 391-413页

作者： Nan XIANG Yiquan SHU Pengyi WANG Menghan YANG Haoran WANG Tao HUANG Junqing GUO fuxiao chen School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China National Key Laboratory for Precision Heat Processing of Metals School of Materials Science and EngineeringHarbin Institute of TechnologyHarbin 150001China College of Mechanical&Electrical Engineering Shaanxi University of Science&TechnologyXi’an 710021China Provincial and Ministerial Co-construction of Collaborative Innovation Center for Non-ferrous Metal new Materials and Advanced Processing Technology Luoyang 471023China

Heterogeneous pressure-carrying medium was employed to establish a differentiated pressure field on sheet metal in flexible die forming process in this work,which aimed at matching the non-symmetric shape of target component and improving metal inflow to avoid local tensile ***,metal inflow corresponding to the differentiated pressure field was analytically *** of a typical non-symmetric shell component was experimentally and numerically studied based on the proposed *** with forming processes based on the uniform pressure,difference of metal inflow in two sides of the non-symmetric component increased from 2.16 mm to 3.36 mm and metal inflow in critical region increased by 11.9%when differentiated pressure field(taking heterogeneous elastomer#4–3 for example)was *** resultant maximum thinning ratio decreased by 4.2% and the uniformity of shell thickness increased by 16.9%.With the decrease of Shore hardness of elastomer in the formed region,stress path in the ready-to-form region transferred towards the bi-axial tension stress state,i.e.,stress ratio(a)***,stress triaxiality(η)in characteristic regions were regulated appropriately,which decreased the risk of tensile *** was attributed to the decreased normal pressure and frictional resistance at sheet/elastomer interface in the formed region.

关键词： Aluminum alloys Finite element method Metal forming Plastic deformation Sheet metal

Studies on the isolation and culture of protoplasts from Kappaphycus alvarezii

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Acta Oceanologica Sinica 2014年第10期33卷 114-123页

作者： ZHANG Si LIU Cui JIN Yuemei CHI Shan TANG Xianming chen fuxiao FANG Xu LIU Tao National Marine Environmental Forecasting Center College of Marine Life Sciences Ocean University of China Hainan Provincial Fisheries Research Institute School of Life Science Shandong University

In this study, protoplasts were successfully isolated from Kappaphycus alvarezii using snail enzymes, abalone enzymes and cellulase. The optimum enzymic ratio was fixed to be 20% of abalone enzyme, 12% of cellulase and the osmotic stabilizer was 2.0 mol/L glucose. The optimum enzymic hydrolysis conditions were found to be dark enzymolysis at 30°C continuing for 4.0 h. The resultant density and yield of protoplasts achieved 32.60×10^4 mL-1, 65.20×10^4 g-1 tissue for Kappaphycus alvarezii. Finally, under the temperature of 20°C, light intensity of 1 500–2 000 lx and photoperiod of 12 h/d, two developmental pathways were investigated：（1） callus-like cell mass and regenerated plantlet occurred on protoplast;（2） young shoots and calluslike cell mass occurred in tissue blocks after enzymolysis.

关键词： Kappaphycus alvarezii protoplast regenerated plantlet callus-like young shoots

Research on Superplasticity and Superplastic Extrusion of MB26 Magnesium Alloy

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Journal of Materials Science & Technology 2001年第1期17卷 147-148页

作者： fuxiao chen Juanhua SU Yunlin YANG and Hongtao in Dept. of Material and Engineering, Luoyang institute of Technology, Luoyang 417039, China Dep. of Mater. Luoyang Inst. of Technol. Luoyang 417039 China

The superplastic flow characteristics of hot extruded MB26 Mg alloy under the conditions of tension are studied. The effects of deformation temperature and strain rate on superplasticity are analyzed. On the other han... 详细信息

关键词： deformation temperature flow characteristics Mg alloy strain rate

Wall Thinning Characteristics of Ti-3Al-2.5V Tube in Numerical Control Bending Process

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Journal of Shanghai Jiaotong university(Science) 2019年第5期24卷 647-653页

作者： HUANG Tao WANG Kun ZHAN Mei GUO Junqing chen Xuewen chen fuxiao SONG Kexing School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang471023HenanChina Collaborative Innovation Center of Nonferrous Metals of Henan Province Luoyang471023HenanChina State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwesternPolytechnical UniversityXi'an710072China

A finite element(FE) model for the numerical control(NC) bending of Ti-3 Al-2.5 V titanium alloy seamless tube is established, considering the variation in the contractile strain ratio(CSR) and elastic modulus(E). The wall thinning characteristics of Ti-3 Al-2.5 V tube under different geometric and process conditions were investigated. The results showed that the CSR-E variation can change the wall thickness, but has no remarkable effect on the change characteristics. The reasonable parameter ranges are as follows: a bending-radius range not less than 1.5 times the outer diameter, a bend angle up to 180?, and a mandrel extension of 0-3 mm. The friction coefficient between the pressure die and the tube should be in the range of 0.20-0.35, and between the bending die and the tube should be in the range of 0.05-0.15. As long as the performance meets the requirements, the relative push-assistant speed should be as small as possible.

关键词： titanium alloy tube numerical control bending wall thinning contractile strain ratio elastic modulus

齿轮钢20CrMnTi在1000℃时的变形抗力数学模型

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热加工工艺 2012年第4期41卷 49-50页

作者：马璟陈拂晓河南科技大学材料科学与工程学院河南洛阳471003

1000℃时在Gleeble-1500热模拟试验机上对20CrMnTi进行热压缩试验,得到了其应力-应变曲线,采用Matlab软件对试验数据进行拟合,得到了变形速率在0.01、5 s-1时的变形抗力模型。结果表明,利用该模型得到的计算值与试验值非常接近,这为20Cr... 详细信息

1000℃时在Gleeble-1500热模拟试验机上对20CrMnTi进行热压缩试验,得到了其应力-应变曲线,采用Matlab软件对试验数据进行拟合,得到了变形速率在0.01、5 s-1时的变形抗力模型。结果表明,利用该模型得到的计算值与试验值非常接近,这为20CrMnTi热成形时工艺参数的制定提供了参考。

关键词： 20CrMnTi 压缩试验变形抗力模型

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深孔薄壁件正挤压凹模的有限元分析

热加工工艺 2009年第15期38卷 132-135页

作者：赵健陈拂晓郑州航空工业管理学院机电工程学院河南郑州450015 河南科技大学材料科学与工程学院河南洛阳471039

针对用于深孔薄壁件挤压的典型正挤压凹模,在不作厚壁圆筒简化并施加非均布载荷的情况下,采用有限元法进行受力和变形情况的分析,计算结果更接近于实际,并进而得到组合凹模配合面过盈量、切向应力和预紧圈外径的关系图。利用此关系可以... 详细信息

针对用于深孔薄壁件挤压的典型正挤压凹模,在不作厚壁圆筒简化并施加非均布载荷的情况下,采用有限元法进行受力和变形情况的分析,计算结果更接近于实际,并进而得到组合凹模配合面过盈量、切向应力和预紧圈外径的关系图。利用此关系可以方便地选取外模圈尺寸和相应的内外模圈配合面的过盈量,为实现组合凹模的设计提供更加精确的设计依据,在实际生产中有较好的应用价值。

关键词：深孔薄壁挤压组合凹模有限元分析

Study of the Compensatory Growth Following Starvation of Juvenile Golden Pompano Trachinotus ovatus

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Animal Husbandry and Feed Science 2015年第3期7卷 178-181,190页

作者： Liu Longlong Luo Ming chen fuxiao Tan Wei Zhang Junbin Li Xiangmin College of Fisheries and Life Science Shanghai Ocean University Hainan Provincial Fisheries Research Institute

A starvation trial was conducted to determine compensatory growth of the juvenile golden pompano Trachinotus ovatus which were deprived of food for 1, 2, 5 and 7 days respectively. The results of tests in outdoor cement pools and net pens showed that, in the first 15 days and 30 days, the growth of 1 day and 2 days-deprived groups was probably the same with that of control group, which accorded with fully compensatory description. However, the weight of 5 days and 7 days-deprived fingerlings were lower than that of the control group, which accorded with the description of the partial compensatory growth. As the starvation prolonged, feed conversion efficiency of the starved groups increased and was higher than the control group. Meanwhile, feeding rate also increased, but the fish of 1 day and 2 days-deprived groups was lower than that of the control group, and feeding quantity reduced and was lower than that of the control group. It suggested that the mechanism of compensatory growth was mainly due to improving feed conversion efficiency. Fish biochemical composition was analyzed： the water content and ash of fish sample increased due to starvation, while the lipid and protein decreased. The loss of lipid was greater than that of the protein, and the biochemical composition of fish in each group was restored to the control level by the end of the experiment. It suggested that Trachinotus ovatus may mainly consume lipid during the period of starvation.

关键词： Trachinotus ovatus Juvenile Net pens Starvation Compensatory growth Feed conversion efficiency Fish biochemical composition