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

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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

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

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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

Effect of high shear rate on solidification microstructure of semisolid AZ91D alloy

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中国有色金属学会会刊：英文版 2010年第S3期20卷 868-872页

作者：朱光磊徐骏张志峰刘国钧 General research institute for non-ferrous metals

To investigate the effects of rotation speed and shearing time on morphology of semisolid AZ91D alloy,experimental work was undertaken using a twin-screw slurry *** results show that increasing the rotation speed and reasonable time can give rise to substantial grain refinement during continuous shearing stage,which can be attributed to the increasing of effective nucleation rate caused by the extremely uniform temperature due to high shear rate and high degree of *** with low rotation speed at the same thermal condition,the analysis indicates that the microstructures obtained at high rotation speed are homogenous spherical and fine grains instead of dendritic or rosette and exhibits uniform distribution in the eutectic matrix.

关键词： semisolid high shear rate solidification AZ91D rotation speed

Effect of lanthanum addition on microstructure and corrosion behavior of Al-Sn-Bi anodes

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Journal of Rare Earths 2011年第2期29卷 129-132页

作者：侯德龙李德富韩莉纪连芹 General research institute for non-ferrous metals

Novel Al-Sn-Bi anodes with and without lanthanum （La） were *** evaluate the corrosion properties of the anodes,constant current and dynamic loop tests were carried out to determine its efficiency and corrosion *** microscopy （OM）,transmission electron microscopy （TEM） and energy spectrum analysis techniques were used to examine and analyze microstructure and corrosion behavior of the *** result showed that the Al-Sn-Bi anodes with La additions revealed higher current efficiency and anticorrosion in artificial *** phase of anodes with La additions got more homogenous than that without La *** grains were fined and the amount of segregation Fe-phase was reduced.

关键词： Al-Sn-Bi sacrificial anodes lanthanum microstructure comprehensive property rare earths

Microstructure,Impact Fatigue Resistance and Impact Wear Resistance of Wear Resistant Low Cr-Si Cast Iron

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Journal of Iron and Steel research International 2001年第2期8卷 47-50页

作者： LI Wei TU Xiao-hui SU Jun-yi ZHOU Qing-de Xi'an Jiaotong University guangzhou research institute of non-ferrous metals

The effect of alloying element (Ni, Co, Mn) on P doped Fe 5 3° low angle grain boundary (GB) embrittlement was investigated by the Recursion method. The model of dislocations was used to construct the atomic structure for the P doped GB. The result indicated that the role of impurity and alloying element segregation to GB can be studied with BOI and the difference between their segregation energies at GB and at free surface (FS) (Δ E=E gb seg - E fs seg ). The BOI results showed that P leads the 'loosening' of the 5 3° low angle GB and decreases the cohesion strength of P doped GB when the alloying element (Ni, Co, or Mn) is added into the P doped 5 3° low angle GB. The Δ E value reveals that the alloying element Ni, Co and Mn have higher energy at P doped 5 3° low angle GB, indicating it serves as a GB embrittler. The BOI results and Δ E calculation were comparable with each other, and they are also consistent with the experimental results, which confirm the embrittling effect of alloying element (Ni, Co, Mn) on P induced GB embrittlement.

关键词： embrittlement alloying element grain boundary

Evolution of Hydrogen Storage Alloys Prepared by Special Methods

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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

Optimization of Processing Parameters for Laser Powder Deposition using Finite Element Method

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Journal of Wuhan University of Technology(Materials Science) 2010年第5期25卷 832-837页

作者：付垚 State Key Laboratory of non-ferrous metals and Processes General Research Institute for Non-ferrous Metals

In order to investigate the effects of powder materials and processing parameters on thermal and stress field during laser powder deposition （LPD）, a finite element model was developed with the help of ANSYS software. The finite element model was verified by the comparison between the experimental results and computed results. Then LPD processes with different powder materials and processing parameters were simulated by using the FE model. The results show that less difference of thermal conductivity and thermal expansion coefficient between powder material and substrate material produces lower residual stress; higher laser power, laser scanning speed and smaller laser beam diameter can lead higher peak temperature and higher residual stress. The research opens up a way to rational selection of the powder materials and processing parameters for ensured quality.

关键词： laser powder deposition thermal field stress field powder material processing parameters

Investigation on the electrochemical behaviours of Mg_(2-x)Cr_xNi negative electrode

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Rare metals 2003年第2期22卷 144-149页

作者： XUE Jianshe, WANG Lijun, LUO Yuanhui, LI Guoxun, DU Jun, HU Guangyong, and WANG ChaoqunGeneral research institute for non-ferrous metals, Beijing 100088, China (Received 2002-09-01) Generald research institute for non-ferrous metals 北京 100088

A series of Mg_(2-x)Cr_xNi alloy powder has been produced by combination ofsolid-state diffusion with mechanical grinding (MG). X-ray diffraction patterns show that the alloypowders have an amorphous structure and great increase in the specific surface. Electrochemicaldetection results indicate that the partial substitution of Mg by Cr in Mg_2Ni alloy improves thecycle life of this alloy greatly, which gets up to 100 cycles at 200 mA/g mass discharge current,keeping its mass discharge capacity over 200 mA.h/g. In the meanwhile, partial replacement of Mg byCr also increases the mass discharge capacity compared with Mg_2Ni alloy. With the increasing ofmass discharge current and content of Cr in Mg_(2-x)Cr_xNi, the cycle life of the alloys areincreased and the decay of mass discharge capacity slows down.

关键词： electrochemistry hydrogen storage alloy Ni-MH battery mechanicalgrinding Mg_2Ni

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

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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