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Journal of Rare Earths 2014年第6期32卷 526-531页

作者：姚青荣唐莹周怀营邓健秋王仲民潘顺康饶光辉朱其明 School of Materials and Engineering Central South University School of Materials Science and Engineering Guilin University of Electronic Technology Guangxi Key Laboratory of Information Materials Guilin University of Electronic Technology School of Science Guangxi University for Ationalities

The effect of rapid solidification on structure and electrochemical performance of the LaNi4.5Co0.25Al0.25 hydrogen storage alloy was investigated by X-ray powder diffraction and a simulated battery test, including maximum capacity, cycling stability, self-discharge, and high-rate discharge ability （HRD）. All the melt-spun alloys were single-phase with the CaCu5-type structure （space groupP6/mmm）. In comparison to the as-cast alloy, the rapidly quenched alloys manifested an improved homogeneity of com-position and expanded lattice parameters. The electrochemical measurements showed that the activation property, cycling stability and self-discharge of the alloy electrodes were also improved for the rapid solidified alloys. The HRDof the as-cast alloy was better than those of all the rapidly solidified alloys. As the quenching rate increased, the HRD and exchange current density first decreased and then increased.

关键词： hydrogen storage alloy electrochemical properties rapid solidification quenching rate rare earths

Crystallographic alignment and magnetic anisotropy in melt-spun Nd-Fe-B/α-Fe composite ribbons with different neodymium contents

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Journal of Rare Earths 2011年第5期29卷 471-473页

作者：王磊陈静武岳明刘荣明刘卫强张东涛张久兴张朋越葛洪良 College of Materials Science and Engineering Beijing University of Technology Anhui Earth-panda Advance Magnetic Material Co. Ltd. Magnetism Key Laboratory of Zhejiang Province China Jiliang University

Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd2Fe14B phase perpendicular to the ribbons surface at low wheel speed,but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons,indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd2Fe14B phase in the ribbons,and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.

关键词： crystallographic alignment magnetic anisotropy Nd content quenching rate coercivity rare earths

Mechanical behavior of Cu-Zr bulk metallic glasses (BMGs): A molecular dynamics approach

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Chinese Physics B 2013年第9期22卷 490-495页

作者： Muhammad Imran Fayyaz Hussain Muhammad Rashid Yongqing Cai S.A.Ahmad Department of Physics Simulation Lab The Islamia University of Bahawalpur Department of Physics National University of Singapore2 Science Drive 3117542Singapore

In the present work, three-dimensional molecular dynamics simulation is carried out to elucidate the nanoinden- tation behaviors of CuZr Bulk metallic glasses （BMGs）. The substrate indenter system is modeled using hybrid interatomic potentials including both many-body Finnis Sinclair （FS） and two-body Morse potentials. A spherical rigid indenter （diameter= 60 A（1 A = 10 ^-10 m）） is employed to simulate the indentation process. Three samples of BMGs including Cu25Zr75, CusoZr50, and Cu75Zr25 are designed and the metallic glasses are formed by rapid cooling from the melt state at about 2000 K. The radial distribution functions are analyzed to reveal the dynamical evolution of the structure of the atoms with different compositions and different cooling rates. The mechanical behavior can be well understood in terms of load-depth curves and Hardness-depth curves during the nanoindentation process. Our results indicate a positive linear relationship between the hardness and the Cu concentration of the BMG sample. To reveal the importance of cooling rate provided during the processing of BMGs, we investigate the indentation behaviors of CusoZr50 at three different quenching rates. Nanoindentation results and radial distribution function （RDF） curves at room temperature indicate that a sample can be made harder and more stable by slowing down the quenching rate.

关键词： Bulk metallic glasses （BMGs） nanoindentation deformation quenching rate

Residual stress and precipitation of Mg-5Zn-3.5Sn-1Mn-0.5Ca-0.5Cu alloy with different quenching rates

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Journal of Magnesium and Alloys 2021年第2期9卷 604-612页

作者： Cong Wang Tianjiao Luo Yunteng Liu Qiuyan Huang Yuansheng Yang Institute of Metal Research Chinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China Shandong Key Laboratory for High Strength Lightweight Metallic Materials Advanced Materials InstituteShandong Academy of SciencesShandong 250014China

The effect of the quenching rate after solution treatment on the residual stress and precipitation behavior of a high strength Mg-5 Zn-3.5 Sn-1 Mn-0.5 Ca-0.5 Cu plate is studied.The simulation results show decreasing temperature gradient in the plate with decreasing quenching rate,which leads to weakened inhomogeneous plastic deformation and decreased residual stress.No dynamic precipitation on the grain boundary happens after either cold water cooling or air cooling,however,air cooling leads to dynamic precipitation of Mg-Zn phase on Mn particles around which a low-density precipitate zone develops after aging treatment.Moreover,the fine and densely distributed Mg-Zn precipitates observed after aging treatment of the cold water cooled alloy are replaced by coarse precipitates with low density for the air cooled alloy.Both the low-density precipitate zone near Mn particles and the coarsening of precipitates are the source of the decrease in hardness and tensile properties of the air cooled alloy.The residual stress drops faster than the hardness with decreasing quenching rate,which makes it possible to lower the residual stress without sacrificing too much age-hardening ability of the alloy.

关键词： Mg-5Zn-3.5Sn-1Mn-0.5Ca-0.5Cu alloy Solution treatment quenching rate Residual stress Precipitation Age-hardening

ON THE CAUCHY PROBLEM FOR A REACTION-DIFFUSION SYSTEM WITH SINGULAR NONLINEARITY

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Acta Mathematica Scientia 2013年第4期33卷 1031-1048页

作者：周军 School of Mathematics and Statistics Southwest University

We consider the growth rate and quenching rate of the following problem with singular nonlinearityfor some positive constants b：, b2 （see Theorem 3.3 for the parametersfor some constantsHence, the solution （u, v） quenches at the originx = 0 at the same time ＇1＇（see Theorem 4.3）. We also tind various other conditions tor the solution to quench in a finite time and obtain the corresponding decay rate of the solution near the quenching time.

关键词： Cauchy problems singular nonlinearity growth rate quenching rate

quenching Estimates for Reaction-diffusion Equations with Nonstandard Growth Conditions

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Chinese Quarterly Journal of Mathematics 2013年第3期28卷 408-416页

作者： LIU Bing-chen HONG Zhen-zhen College of Science China University of Petroleum Qingdao 266580 China

This paper deals with reaction-diffusion equations involving nonstandard growth conditions, subject to homogeneous Neumann boundary conditions. The complete classification is established for simultaneous and non-simultaneous quenching under suitable assumptions on initial data. Moreover, quenching sets and quenching rates are obtained.

关键词： nonstandard growth conditions simultaneous quenching non-simultaneous quenching quenching set quenching rate