检索结果-南通市图书馆

Evolution of Hydrogen Storage Alloys Prepared by Special Methods

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2004年第z1期22卷 222-227页

作者： Guo Hong Zhang Ximin Jing Hai Li Chengdong Xu Jun National engineering and Technology Research Center for non-ferrous metals Composites General Research Institute for Non-Ferrous Metals Beijing 100088 China National Engineering and Technology Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous Metals Beijing 100088 China National Engineering and Technology Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous Metals Beijing 100088 China National Engineering and Technology Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous Metals Beijing 100088 China National Engineering and Technology Research Center for Non-Ferrous Metals Composites General Research Institute for Non-Ferrous Metals Beijing 100088 China

Microstructure characteristics and electrochemical properties of hydrogen storage alloys prepared by gas atomization, melt spinning and strip casting respectively were *** advantages, disadvantages and research development of the above methods for preparing hydrogen storage alloys were *** strip casting is a new special means for preparing AB5 rare earth hydrogen storage alloys of high performance and low cost, and the study of the strip casting for preparing hydrogen storage alloys is presented specially.

关键词： hydrogen storage alloys gas atomization melt spinning strip casting rare earths

Effect of homogenization on microstructure and properties of WE91 alloys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2013年第8期31卷 830-836页

作者：马鸣龙张奎李永军李兴刚石国梁 State Key Laboratory for non-ferrous metals and Processes Beijing General Research Institute for Non-Ferrous Metals

The microstructure and properties of the Mg-9Y-1MM-0.6Zr alloy were studied by scanning electron microscopy, optical microscopy, transmission electron microscopy, hardness and tensile testing. Homogenization was confirmed, and the solidification model was established. The as-cast alloy was mainly composed of ct-Mg and eutectic structures. The suitable homogenization pa- rameters were 535℃ for 18 h. Most of the eutectic structure dissolved in this process. Only the Mg4.26Y95.74 and Mg12 （MM） phases were remained in, and only a few microstructure occurred for prolonged time. The ultimate tensile strength of the alloy increased up to 232 MPa after homogenization, but the yield strength and the elongation were almost as same as the as-cast state. In the as-cast al- loys the cracks started in the eutectic structure, and then intergranular fracture occurred, but in the homogenate alloys residual phases became the source of the cracks and then tmnscrystalline fracture took place. The most important roles of homogenization were the decomposition of the eutectic structure, furthermore the intergranular fracture turned into a transcrystalline fracture, which was one of the main reasons to increase the strength of the alloys.

关键词： rare earth magnesium alloy homogenization microstructure mechanical property

Microstructural evolution of aluminum alloy 7B04 thick plate by various thermal treatments

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1期18卷 40-45页

作者：李志辉熊柏青张永安朱宝宏王锋刘红伟 State Key Laboratory for Fabrication and Processing of non-ferrous metals General Research Institute for Non-ferrous Metals

The microstructure of an AA 7B04 alloy in the form of plate was investigated using differential scanning calorimetry(DSC)and TEM analysis *** properties and electrical conductivity of AA 7B04 under various heat treatment conditions were also *** results reveal that peak-aged microstructure contains GP zones and η' precipitates *** retrogressing and reaging(RRA),the η' and η precipitates disperse in the alloy matrix,and the η precipitates distribute coarsely and sparsely,decorating the grain boundaries,together with precipitate free zones(PFZs)around *** is also shown that selecting of suitable heat treatments can provide optimal precipitates in matrix and at grain boundaries,which gives rise to a combination of high strength and stress corrosion cracking(SCC)resistance in such materials.

关键词：铝合金显微结构热处理金属学

Study on Fine Structure of Gas Atomized LaNi_5-based Alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2003年第5期19卷 425-427页

作者： Hai JING, Hong GUO, Shuguang ZHANG, Zili MA and Shaoming ZHANGNational engineering Research Center for non-ferrous metals Composites, General Research Institute for non-ferrous metals, Beijing 100088, China National engineering Research Center for non-ferrous metals Composites General Research Institute for Non-ferrous MetalsBeijing 100088 China

The fine structure of hydrogen storage alloy powders MiNi4.3-xCoxMr0.4AI0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.

关键词： Hydrogen storage alloys Gas atomization Rietveld analysis Crystal structure

Effects of isothermal homogenization on microstructure evolution of Mg-7Gd-5Y-1MM-0.5Zr alloy

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2015年第4期33卷 439-444页

作者：李蒙李兴刚张奎李永军马鸣龙石国梁袁家伟刘靖宝 State Key Laboratory for Fabrication and Processing of non-ferrous metals General Research Institute for Non-Ferrous Metals

Optical microscopy （OM）, scanning electronic microscopy （SEM） and X-ray diffraction （XRD） were performed to inves- tigate the influence of homogenization on the microstructures of the Mg-7Gd-5Y-1MM （Ce-rich RE）-0.5Zr magnesium alloy. The results indicated that α-Mg, Mg24（GdY）5 phase, Mg5（GdY） phase and Mg12MM phase coexisted together in as-cast alloy; the micro- structures were largely characterized by α-Mg matrix and gray globular or elliptic ball Mg12MM phase, in addition to those with cubic block Mg24（GdY）5 phase after homogenization; the reasonable homogenization regime was maintained at 530 ℃ for 32 h.

关键词： homogenization treatment magnesium microstructure evolution rare earths

Break-up Process of Perturbed Molten Metal Jet and Preparation of Lead-Free Solder Balls

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2004年第z2期22卷 174-177页

作者： He Lijun Zhang Shuguang Zhang Shaoming Xu Jun Shi Likai National engineering Research Center for non-ferrous metals Composites General Research Institute for Non-Ferrous MetalsBeijing 100088China

Solder balls, which are used in advanced electronics packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) to substitute the leads and realize the electrical and mechanical connections between substrate and chip,have severe specifications in diameter tolerance, roundness and surface quality, and therefore challenge the traditional technologies for fabrication of metallic particles and powders. The present work made a survey of perturbed molten metal jet break-up process, observed the formation and growth of capillary wave of tin-lead melt jet by way of rapid solidification, and on the basis of the above research, successfully obtained tin-lead eutectic and Sn-4.0Ag-0.5Cu lead free solder balls with tight distribution and good sphericity of particles through optimization of processing parameters, forming a solid base for cost effectively producing solder balls.

关键词： solder balls jet break-up capillary wave perturbation

Homogenization heat treatment of Mg-7.68Gd-4.88Y-1.32Nd-0.63Al-0.05Zr alloy

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第5期32卷 445-450页

作者：张国栋李兴刚马鸣龙李永军石国梁袁家伟张奎 State Key Laboratory for Fabrication and Processing of non-ferrous metals Beijing General Research Institute for Non-ferrous Metals

The microstructures and mechanical properties of the Mg-7.68Gd-4.88Y-1.32Nd-0.63A1-0.05Zr magnesium alloy were investigated both in the as-cast condition and after homogenization heat treatment from 535 to 555 ℃ in the time range 0-48 h by op- tical microscopy, scanning electron microscopy and hardness measurement. The as-cast alloy consisted of ct-Mg matrix, Mgs（Y0.5Gd0.5） phase which is a eutectic phase, strip of Al2（Y0.6Gd0.4） phase, little A13Zr and Mg（Y3Gd） phase. With the increasing of homogenization temperature and time, the Mgs（Y0.5Gd0.5） phase was completely dissolved into the matrix. The Al2（Y0.6Gd0.4） phase was almost not dissolved which impeded grain boundaries motion making the grain size almost not changed in the process of ho- mogenization. The optimum homogenization condition was 545 ℃/16 h. The tensile strength increased, yield strength decreased and the plasticity improved obviously after 545 ℃/16 h homogenization treatment.

关键词： Mg-Gd-Y-Nd-AI alloy homogenization second phase hardness rare earths

Corrosion behavior of extrusion, under-aged, peaked-aged and over-aged WE93 alloys in Na HSO_3 solutions

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2014年第12期32卷 1170-1174页

作者：蒋全通马鸣龙张奎李兴刚李永军石国梁袁家伟 State Key Lab for non-ferrous metals and Process General Research Institute for Non-ferrous Metals

The corrosion behaviors of extrusion, under-aged, peaked-aged and over-aged WE93 alloys in Na HSO3 solutions were investigated by optical microscopy（OM）, scanning electron microscopy（SEM） and X-ray diffraction（XRD）.The weight loss rates, corrosion morphologies and polarization curves were *** peak-aged specimen in Na HSO3 salt spray had the highest corrosion rate of 0.9787 mg/cm2/d, while extrusion specimen led to the lowest of 0.2184 mg/cm2/*** specimens could be arranged in decreasing order of corrosion rates： extrusion 〈under-aged〈over-aged〈peak-aged. Polarization curves also gave effective evaluation of corrosion rates in agreement. The NaHSO3 played a great role in the corrosion behaviors of WE93 alloys. The main reasons were that HSO3- developed a reaction： O2＋2HSO3 ＋2e→2HSO42→2H＋＋2SO42- to generate H＋, accelerating the process of corrosion reaction. SO4 2- stimulated corrosion and led to an autocatalytic type of reaction： MgZ＋＋SO4^2-＋7H2O→MgSO4-7H2O. XRD characterized that Mg（OH）2 and MgSO4·7H2O were the main corrosion products.

关键词： corrosion behaviors WE93 alloy Na HSO3 rare earths

Microstructure evolution of 7050 aluminum alloy during hot deformation

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2期20卷 189-194页

作者：李俊鹏沈健闫晓东毛柏平闫亮明 General Research Institute for non-ferrous metals

Hot compression of 7050 aluminum alloy was performed on Gleeble 1500D thermo-mechanical simulator at 350 ℃ and 450 ℃ with a constant strain rate of 0.1 s-1 to different nominal strains of 0.1, 0.3 and 0.7. Microstructures of 7050 alloy under various compression conditions were observed by TEM to investigate the microstructure evolution process of the alloy deformed at various temperatures. The microstructure evolves from dislocation tangles to cell structure and subgrain structure when being deformed at 350 ℃, of which dynamic recovery is the softening mechanism. However, continuous dynamic recrystallization (DRX) occurs during hot deformation at 450 ℃, in which the main nucleation mechanisms of DRX are subgrain growth and subgrain coalescence rather than particle-simulated nucleation (PSN).

关键词： microstructure evolution dynamic recovery dynamic recrystallization hot deformation 7050 alloy