检索结果-南通市图书馆

Study on direct-chain diacid modified phenolic resin for al-alloy casting

在线全文

学校读者我要写书评

暂无评论

China Foundry 2005年第1期2卷 28-33页

作者： Yundong JI Jirong LUO Moyin LI School of Materials Huangzhong University of Science and Technology Wuhan 430074 Hubei P. R. China Wuhan Life Chemistry and Industry Co. Wuhan 430011 Hubei P. R. China

Resin coated sand (RCS) with phenolic resin matrix can hardly be collapsed when it is used in al-alloy casting. Adding collapsing agent and reducing the concentration of resin are solutions adopted by workers, but these methods tend to reduce the initial strength of RCS. Synthesis of modified phenolic resin with direct-chain diacid DAn (/JS=6, where n means carbon amount) was studied here. The effects of the addition of modifying agent on molecular weight, gel time and softening point were investigated. Optimal addition of DAn (10% phenol) was obtained by testing the initial and retained flexural strengths of the modified resin. FT-IR spectra showed that carbonyl shifts to higher wave number. With the use of TG, SEM and strength loss curves, the relation between initial and retained strengths was analysed. Tests on the heated deformation curve, before and after resin modification, show that PF-DA10 has the characteristic of higher initial and retained strengths together.

关键词： direct-chain diacid PF resin modify al-alloy casting RCS

Effect of Squeeze Cast Process Parameters on Fluidity of Hypereutectic al-Si alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2008年第1期24卷 7-11页

作者： Jong-Kyu Baek Hae-Wook Kwon School of Materials Science and Engineering Yeungnam University Gyeongsan 712-749 Korea

The effects of processing variables on the fluidity of hypereutectic al-Si alloy melt during squeeze casting were *** maximum fluidity of al-16.0%Si alloy during squeeze casting was obtained under the applied pressure of 30 *** fluidity increased with *** fluidity increased with silicon content in the range from 12.0% to 20.0%.That was decreased respectively by eutectic modification and primary silicon refinement.

关键词： Squeeze casting al-alloy Fluidity Melt treatment

FEM analysis of stress evolution in twin wire welding of al alloy

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2005年第S2期15卷 5-10页

作者：孟庆国方洪渊杨建国姬书得 State Key Laboratory of Advanced Welding Production technology Harbin Institute of Technology Harbin 150001 China

Twin wire weld temperature results calculated by classical double ellipsoid heat source model are bigger than the experimental results. By analyzing the shape of twin wire welding arcs and the track of droplets transition, the phenomena that both the fore arc and rear arc of twin wire welding deflect to the middle of the two arcs is found. Based on this the double ellipsoid heat source model is amended, and a heat source model which can be applied to calculate the temperature field of twin wire welding was put forward. This model is testified by actual experiment of temperature sampling. Then, the evolution regularities of longitudinal and transverse stress for 2219 sheets were investigated under the condition of twin wire welding. The result shows that longitudinal residual stress value of twin wire welding is 10% higher than that of the single wire welding.

关键词： numerical simulation twin wire welding al-alloy

‘Size effect’ related bending formability of thin-walled aluminum alloy tube

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2013年第1期26卷 230-241页

作者： Li Heng Yang He Zhang Zhiyong Wang Zekang State Key Laboratory of Solidification Processing School of Materials Science and Engineering Northwestern Polytechnical University

aluminum alloy （al-alloy） thin-walled （D/t ＆gt; 20, diameter D, wall thickness t） bent tubes have attracted increasing applications in many industries with mass quantities and diverse specifications due to satisfying high strength to weigh ratio requirements of product manufacturing. However, due to nonlinear nature of bending with coupling effects of multiple factors, the similarity theory seems not applicable and there occurs a challenge for efficient and reliable evaluation of the bending formability of thin-walled tube with various bending specifications. Considering the unequal deformation and three major instabilities, the bending formability of thin-walled al-alloy tube in changing tube sizes such as D and t are clarified via both the analytical and FE modeling/ simulations. The experiments of rotary draw bending are conducted to validate the theoretical models and further confirm ＇size effect＇ related bending formability. The major results show that （1） The anti-wrinkling capability of tube decreases with the larger D and smaller t, and the effect significance of t is larger than that of D even under rigid supports; （2） The wall thinning increases with the larger D and smaller t, and this tendency becomes much more obvious under rigid supports; （3） The cross-section deformation increases with the larger D and smaller t according to the analytical model obtained intrinsic relationship, while this tendency becomes opposite due to the nonlinear role of mandrel die; （4） The size factor D/t can be used as a nondimensional index to evaluate both the bending formability regarding the wall thinning and cross-section deformation.

关键词： al-alloy Bending formability Flattening Size effect Tube bending Wall thinning Wrinkling

Corrosion Penetration and Crystal Structure of AA5022 in HCl Solution and Rare Earth Elements

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2005年第3期21卷 324-330页

作者： A.A.El-Meligi S.H.Sanad A.A.Ismail A.M.Barakat Electrochem. and Corrosion Lab. Physical Chemistry Dept. National Research Centre Dokki Cairo EgypElectrochem. and Corrosion Lab. Physical Chemistry Dept. National Research Centre Dokki Cairo EgypElectrochem. and Corrosion Lab. Physical Chemistry Dept. National Research Centre Dokki Cairo EgypChemistry Dept. Faculty of Science Cairo University Cairo Egypt

al-alloy (AA5022) corrosion penetration (CP) and crystal structure were investigated after running static immersion corrosion tests in 1 mol/L HCl solution and different concentrations of rare earth elements (La3+), (Ce3+) and their combination, at different temperatures. X-ray diffraction (XRD) was used to examine the surface structure before and after immersion, and secondary electron detector (SED) was operated to study surface morphology. In 1 mol/L HCI solution the corrosion penetration increased with increasing temperature and immersion time. The increase of La3+ concentrations up to 1000×10-6 g/L led to the decrease in the corrosion penetration, and the decrease in Ce3+ concentrations up to 50×10-6 g/L decreases the corrosion penetration of the alloy. Mix3 (combination of La3+ and Ce3+) dramatically reduced the corrosion penetration. This suggests that a synergistic effect exists between La3+ and Ce3+. The reaction kinetics both in absence and presence of La3+ and Ce3+ and their combination would follow a parabolic rate law. The XRD patterns revealed that the intensities of certain hkl phases are affected. The crystalline structure has not been deformed either before or after testing and there are no additional peaks except that of the as-received alloy. In the case of accelerating CP, the surface morphology shows that the roughness and voids of surface are increased.

关键词： al-alloy Corrosion penetration Crystal structure XRD

Effect of extrusion on properties of al-based composite

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2010年第12期20卷 2229-2233页

作者： R.DASGUPTA S.DAS S.CHATURVEDI A.K.JHA Advanced Materials and Processes Research Institute CSIR Bhopal 462064Madhya PradeshIndia

An aluminium alloy and its composite with dispersed SiC particles made by liquid metallurgy route were extruded under optimized *** properties were characterized in terms of microstructure,hardness and sliding wear behaviour and then compared between the extruded and cast alloys and composites,in order to understand the benefits of composite and extrusion on the *** was observed that composites drastically increased the hardness and the extruded composites further increased this *** advantage of composites was realized in sliding wear tests.

关键词： extrusion al-alloy composites microstructure wear

Very-High-Cycle-Fatigue of in-service air-engine blades,compressor and turbine

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2014年第1期57卷 19-29页

作者： SHANYAVSKIY A A State Centre for Flights Safety Airport Sheremetievo-1 PO Box 54 Moscow Region Chimkinskiy State 141426 Russia

In-service Very-High-Cycle-Fatigue(VHCF)regime of compressor vane and turbine rotor blades of the al-based alloy VD-17and superalloy GS6K,respectively,was *** crack origination occurred at the lifetime more than 1500 hours for vanes and after 550 hours for turbine *** fractographic investigations have shown that subsurface crack origination in vanes took place inspite of corrosion pittings on the blade *** material behavior reflected lifetime limit that was reached by the criterion *** superalloy GS6K subsurface fatigue cracking took place with the appearance of flat *** phenomenon was discussed and compared with specimens cracking of the same superalloy but prepared by the powder *** turbine blades VHCF regime appeared because of resonance of blades under the influenced gas *** cases of compressor-vanes and turbine blades in-service cracking were discussed with crack growth period and stress equivalent *** to continue aircrafts airworthiness were made for in-service blades.

关键词： subsurface fatigue crack al-alloy superalloy resonance quantitative fractography crack growth period stress level

Investigation　on　Surface　Roughness　for　Press－Finishing　of　aluminium　alloy　with　PCD　Sphere

在线全文

学校读者我要写书评

暂无评论

Journal of Harbin Institute of Technology(New Series) 1996年第2期3卷 58-63页

作者：余兴波王庆超

Press-finishing, a plastic deformation process, can be applied to raise surface precision of a workpiece. This paper introduces a new press-finishing technique for PCD (polycrystal diamond)tool that can press finishing the residual feed trails produced by the diamond tool on the machined surface. The experiments of press-finishing of al-alloy have been performed on an instrument lathe with the press-finishing set-up with a PCD tool. Having investigated the correlation between the surface roughness (Rα)and parameters, such as press-finishing speed (v), feed (f),depth of press (αpp), PCD sphere diameter (Dsph), rigidity coefficient of spring (Ki) etc, the optimum parameters of *** their laws for the press-finishing of al-alloy have been acquired. Some mechanisms for the press-finishing of al-alloy with a PCD tool have been discussed. With appropriate parameters chosen, the sample of al-alloy could be press-finished to a value of Ra =0.026μm from an initial roughness of Ra =0.5μm.

关键词： ss:Artificial diamond polycrystal diamond (PCD) diamond tool press-finishing machining al-alloy precision machining

Synergetic effect of stannate with o-aminophenol on inhibiting H2 evolution of A1 anode in strong alkaline media

在线全文

学校读者我要写书评

暂无评论

Journal of Shanghai University(English Edition) 2007年第4期11卷 426-431页

作者：张燕宋玉苏王源升 Department Of Chemistry and Materials College of Sciences Naval University of Engineering Wuhan 430033 P. R. China Administrative Office of Training Naval University of Engineering Wuhan 430033 P. R. China

The performance of al-alloy anode in 4 mol/L KOH with and without stannate and o-aminophenol at 25℃ and 55℃ was studied by hydrogen collection, potentiodynamic polarization and electrochemical impedance spectrum, o-aminophenol acts as a perfect inhibitor because of its adsorbability and forming chelate complex at its optimum concentration of 0.4 mol/L. Stannate enhances the inhibition of o-aminophenol and improves the activity of al-alloy because of its reduction to tin. There is synergetic effect of stannate with o-aminophenol on the behavior of al-alloy, and the inhibitive efficiency at 55℃ is better than that at 25 ℃.

关键词： o-amniophenol stannate al-alloy hydrogen evolution alkaline media