检索结果-南通市图书馆

Characterization of Al-12Si alloy and its composites in dry sliding friction and wear at elevated temperature

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 2003年第3期13卷 636-640页

作者：杜军刘耀辉于思荣王威 key laboratory of automobile materials of ministry of Education Department of materials Engineering

Al 12Si alloy matrix composites reinforced with Al 2O 3 and carbon fibers respectively as well as with the two fibres were fabricated by squeeze infiltration. The elevated temperature (about 400 ℃) friction and wear behaviors of Al 12Si alloy and its composites were *** results show that the hybrid composites reinforced with Al 2O 3 and carbon fibres are of superior high temperature wear *** critical transition temperature from mild wear to severe wear of the composites reinforced only with Al 2O 3 fiber is improved markedly compared with monolithic Al 12Si alloy, from 200 ℃ to 300 ℃.However, the critical transition temperature of the hybrid composites reinforced with Al 2O 3 and carbon fibers is improved further to 400 ℃.The reinforcing fibers have no significant effect on wear mechanisms of Al 12Si *** dominant mechanisms are ploughing grooves and delamination as well as slight adhesion during mild wear *** subsurface consists of three regions:non peeling delamination layer, microcrack formation and propagation zone, and unaffected *** the dominant mechanism is shifted to severe wear when test temperature exceeds the critical transition temperature.

关键词：铝硅合金复合材料干滑动摩擦磨损高温

Design and Preparation of Steel Slag SMA

在线全文

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(materials Science) 2003年第3期18卷 86-88页

作者：吴少鹏 key laboratory of Silicate materials Engineering of ministry of edueation Wuhan University of Technology

On the basis of the characteristics of high rigidity and excellent friction resistance,a new kind of steel slag SMA (stone matrix asphalt) concrete was designed and *** main processes include aggregate gradation,performance analysis of steel slag before and after aging,preparation methods and properties test of steel slag *** experimental results indicate that the index of steel slag's activation is less than 1 percent,the dynamic stability is 5699 times/mm,and both the residual stability and ratio of frozen splitting strength are more than 80 percent;the friction factor and structure depth are 67.1% and 0.7mm *** results show the steel slag SMA is superior to the common asphalt concrete and SMA that uses common aggregate.

关键词： steel slag SMA design preparation

High Cycle Fatigue Properties of Die-Cast Magnesium Alloy AZ91D with Addition of Different Concentrations of Cerium

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2006年第5期24卷 591-595页

作者：杨友刘勇兵秦淑影方懿 key laboratory of automobile materials ministry of Education Jilin University

The effect of addition of different concentrations of Ce on high-cycle fatigue behavior of die-cast magnesium alloy AZ91D was investigated. Mechanical fatigue tests were conducted at the stress ratio of R = 0.1, and fatigue strength was evaluated using up-and-down loading method. The results show that the grain size of AZ91D alloy is remarkably refined, and the amount of porosity decreases and evenly distributes with the addition of Ce. The fatigue strength of AZ91D alloy at room temperature increases from 96.7 up to 116.3 MPa （ 1% Ce） and 105.5 MPa （2 % Ce）, respectively, at the number of cycles to failure, Nf = 1 × 10^7. The fatigue crack of AZ91D alloy initiates at porosities and inclusions, and propagates along grain boundaries. The fatigue striations on fractured surface appear with Ce addition. The fatigue fracture surface of test specimens shows mixed-fracture characteristics of quasi-cleavage and dimple.

关键词： die-cast magnesium alloy cerium high-cycle fatigue fracture surface analysis rare earths

Deposition of electroless Ni-P/Ni-W-P duplex coatings on AZ91D magnesium 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 2008年第A1期18卷 323-328页

作者：陈晓明李光玉连建设 key laboratory of automobile materials Ministry of EducationCollege of Materials Science and EngineeringJilin University

The electroless Ni-P/Ni-W-P duplex coatings were deposited directly on AZ91D magnesium alloy by an acid-sulfate nickel *** sulphate and sodium tungstate were used as metal ion sources and sodium hypophosphite was used as reducing *** coating was characterized for its structure,morphologies,microhardness and corrosion *** presence of dense and coarse nodules in the duplex coatings was observed by SEM and *** content in Ni-P/Ni-W-P alloy is about 0.65%(mass fraction) and the phosphorus content is 8.18%(mass fraction).The microhardness of the coatings is 622 *** coating shows good adhesion to the *** results of electrochemical analysis,the porosity and the immersion test show that Ni-P/Ni-W-P duplex coatings possess noble anticorrosion properties to protect the AZ91D magnesium alloy.

关键词： Ni-W-P合金镁合金 AZ91D镁合金沉积机理

Preparation of High-Strength Al–Mg–Si/Al_2O_3 Composites with Lamellar Structures Using Freeze Casting and Pressureless Infiltration Techniques

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 944-950页

作者： Ping Shen Juwei Xi Yujie Fu Alateng Shaga Chang Sun Qichuan Jiang key laboratory of automobile materials (ministry of Education) Department of Materials Science and EngineeringJilin University

Lamellar porous alumina scaffolds with the initial solid loadings of 20, 25, and 30 vol% were prepared by freeze casting using 5 μm alumina powders. With the addition of 3 wt% MgO-A1203-SiO2 nanopowders in a eutectic composition as sintering aid, the maximum compressive strength of the sintered scaffolds reached （64 -4- 2） MPa after sintering at 1,773 K for 2 h. The lamellar porous scaffolds were then filled with a molten Al-12Si-10 Mg alloy （in wt%） by pressureless infiltration at 1,223 K in a N2 atmosphere, yielding the shell-like structure of the composites. The compressive strength of the upper part composite with the initial 30 vol% solid loading reached （1,190 ±50） MPa, which was about 3.5 times as large as that of the matrix alloy.

关键词： Biomimetic Metal-matrix composites Porous materials

Formation process, microstructure and mechanical property of transient liquid phase bonded aluminium-based metal matrix composite joint

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 2004年第1期14卷 105-110页

作者：孙大谦刘卫红贾树盛邱小明 key laboratory of automobile materials of ministry of Education School of Materials Science and Engineering Jilin University

The formation process, microstructure and mechanical properties of transient liquid phase (TLP) bonded aluminium based metal matrix composite (MMC) joint with copper interlayer were investigated. The formation process of the TLP joint comprises a number of stages: plastic deformation and solid diffusion (stage 1), dissolution of interlayer and base metal (stage 2), isothermal solidification (stage 3) and homogenization (stage 4). The microstructure of the joint depends on the joint formation process (distinct stages). The plastic deformation and solid diffusion in stage 1 favoure the intimate contact at interfaces and liquid layer formation. The microstructure of joint consists of aluminium solid solution, alumina particle, Al 2Cu and MgAl 2O 4 compounds in stage 2. The most pronounced feature of joint microstructure in stage 3 is the alumina particle segregation in the center of the joint. The increase of joint shear strength with increasing bonding temperature is mainly attributed to improving the fluidity and wettability of liquid phase and decreasing the amount of Al 2Cu brittle phase in the joint. The principal reason of higher bonding temperature (>600 ℃) resulting in lowering obviously the joint shear strength is the widening of alumina particle segregation region that acts as a preferential site for failure. The increase of joint shear strength with increasing holding time is mainly associated with decreasing the amount of Al 2Cu brittle phase and promoting homogenization of joint.

关键词：金属基复合材料制备显微结构机械性能钎焊瞬间液相连接 TLP

Microstructure and mechanical properties of Mg-6Al-0.3Mn-xY alloys prepared by casting and hot rolling

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3期20卷 383-389页

作者：苏桂花张亮程丽任刘勇兵曹占义 key laboratory of automobile materials Ministry of EducationDepartment of Materials Science and EngineeringJilin University

Mg-6Al-0.3Mn-xY(x=0,0.3,0.6 and 0.9,mass fraction,%) magnesium alloys were prepared by casting and hot rolling *** influence of yttrium on microstructure and tensile mechanical properties of the AM60 magnesium alloy was *** results reveal that with increasing the yttrium content,Al2Y precipitates form and the grain size is *** ultimate strength,yield strength and elongation at room temperature are 192 MPa,62 MPa and 12.6%,respectively,for the as-cast Mg-6Al-0.3Mn-0.9Y *** these properties are improved obviously by hot rolling,and the values are up to 303 MPa,255 MPa and 17.1%,respectively,for the rolled Mg-6Al-0.3Mn-0.9Y *** improvement of mechanical properties is attributed to continuous dynamic recrystallization and the existence of highly thermal stable Al2Y precipitate which impedes the movement of dislocation effectively.

关键词： magnesium alloy yttrium hot rolling dynamic recrystallization mechanical properties

Effect of Cr Content on the Compression Properties and Abrasive Wear Behavior of the High-Volume Fraction(TiC–TiB_2)/Cu Composites

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2014年第5期27卷 951-956页

作者： Feng Qiu Yue Han Ai Cheng Jianbang Lu Qichuan Jiang key laboratory of automobile materials Ministry of EducationDepartment of Materials Science and EngineeringJilin University

The （TiC-TiB2）/Cu composites with 50 vol% TiC-TiB2 ceramic particles were successfully fabricated by the combustion synthesis and hot press consolidation in a Cu-Ti-B4C-Cr system. The effects of the Cr content on the microstructures, hardness, compression properties, and abrasive wear behaviors of the composites were investigated. The final products consist of only Cu, TiC, and TiB2 phases, and the ceramic particles are distributed uniformly in these composites. The size of the ceramic particles decreases with Cr addition. As the Cr content increases, the yield strength, ultimate compression strength, microhardness, and abrasive wear resistance of the composites increase, and the fracture strain decreases.

关键词： Metal matrix composites Powder metallurgy Combustion synthesis Abrasive wear

Effect of grain size on corrosion behavior of electrodeposited bulk nanocrystalline Ni

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 2010年第1期20卷 82-89页

作者：秦丽元连建设蒋青 key laboratory of automobile materials of ministry of Education College of Materials Science and Engineering Jilin University

Nanocrystalline (NC) and coarse-grained Ni with different grain sizes (from 16 nm to 2 μm) were fabricated by direct current electrodeposition. Effect of grain size on the electrochemical corrosion behavior of these Ni deposits in different corrosion media was characterized by using potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS) and immersion corrosion test. Results show that in the NaOH or NaCl solution, the NC Ni exhibits improved corrosion resistance with the decrease of grain size. But in H2SO4 solution, the higher grain boundary density accelerates corrosion due to no passive process and the corrosion resistance of NC Ni decreases with refining grain size. The distinct experimental results of NC Ni in corrosion behavior can be reasonably explained by the positive or negative effect of high-density grain boundaries in different corrosion media.

关键词：纳米晶镍晶粒尺寸腐蚀行为 X射线光电子能谱电化学阻抗谱耐腐蚀性能块体氢氧化钠溶液