材料期刊网

INVESTIGATION ON CRYSTALLIZATION KINETICS OF Pd-Cu-Si GLASS

GAO Wenli SUI Zhitong North East University of Technology , Shenyang , China LU Ke LI Shuling WANG Jingtang State Key Laboratory for RSA , Institute of Metal Research , Academia Sinica , Shenyang , China Institute of Metal Research , Academia Sinica , Shenyang 110015 , China

金属学报(英文版)

The crystallization kinetics of Pd-Cu-Si glass was studied by means of diferential scanning calorimetry-Ⅱ.According to Kissinger peak shift methd and Arrhenius equation,the apparent activation energy was calculated.The crystallization kinetics follows Johnson- Mehl-Avrami equation with n=3.0 within 0.15

关键词: amorphous ahoy , null , null , null

Key R&D activities for development of new types of wrought magnesium alloys in China

Transactions of Nonferrous Metals Society of China

Many researchers in China are actively engaged in the development of new types of wrought magnesium alloys with low cost or with high-performances and novel plastic processing technologies. The research activities are funded primarily through four government-supported programs: the Key Technologies R&D Program of China, the National Basic Research Program of China, the National High-tech R&D Program of China, and the National Natural Science Foundation of China. The key R&D activities for the development of new wrought magnesium alloys in China are reviewed, and typical properties of some new alloys are summarized. More attentions are paid to high-strength wrought magnesium alloys and high-plasticity wrought magnesium alloys. Some novel plastic processing technologies, emerging in recent years, which aim to control deformation texture and to improve plasticity and formability especially at room temperature, are also introduced.

关键词: wrought magnesium alloy;microstructure;properties;alloy designing;plastic deformation;research projects;y-zr alloys;mechanical-properties;mg-4y-4sm-0.5zr alloy;grain-refinement;rare-earth;microstructure;gd;phase;temperature;evolution

Laboratory of Solid State Microstructures(LSSMS)

材料科学技术（英文）

关键词:

Y3+掺杂Ce∶Li6Lu(BO3)3闪烁体的发光性能研究

孙丹丹 , 潘尚可 , 任国浩 , 吴云涛 , 商珊珊 , 张国庆

无机材料学报 doi:10.3724/SP.J.1077.2013.12735

针对Ce:Li6Lu(BO3)3晶体有效原子序数(zeff)高的问题,采用低原子序数的Y3+离子部分置换晶体中的Lu3+离子.通过固相合成法制备了Ce:Li6Lu1-xYx(BO3)3(0≤x≤1)固溶体.X射线粉末衍射(XRD)分析表明,该系列固溶体结构与Li6Gd(BO3)3晶体相同,空间群为P21/c.其X射线激发发射(XSL)的发光强度随着Y3+的含量增加而降低,当x=0.5时,固溶体的有效原子序数与Li6Gd(BO3)3闪烁体相当,但XSL发光强度是其1.4倍.Ce:Li6Lu0.5Y0.5(BO3)3的XSL光谱和PL光谱都在400 nm附近出现Ce3+离子的特征峰,可拟合出361和419 nm两个发光分量,分别对应于Ce3+离子的激发态电子的5d1→2F5/2和5d1→2F7/2能级跃迁.Ce:Li6Lu0.5Y0.5(BO3)3固溶体的衰减时间比Ce:Li6Lu(BO3)3略长,为19.6 ns.当x=0.50～0.70时,Ce:Li6Lu1-xYx(BO3)3(0≤x≤1)闪烁体比较适合作为中子探测材料.

关键词: 固相合成 , Ce∶Li6LU1-xYx(BO3)3 , X射线激发发射谱 , PL光谱 , 衰减时间

Two-step magnetization in a spin-chain system on the triangular lattice: Wang-Landau simulation

Physical Review B

The Wang-Landau algorithm is used to study the thermodynamic and magnetic properties of triangular spin-chain system based on two-dimensional Ising model in order to understand the magnetic-order dynamics in Ca(3)Co(2)O(6) compound. The calculated results demonstrate that the equilibrium state of the rigid spins produces the two-step magnetization curve at low temperature even when the random-exchange term is considered. This work indicates that the four-step magnetization behavior observed experimentally must be due to the nonequilibrium magnetization.

关键词: calcium compounds;exchange interactions (electron);Ising model;magnetisation;thermodynamics;one-dimensional ca3co2o6;density-of-states;compound ca3co2o6;phase-diagram;proteins;crystal

富集10B的Ce：Li6Lu（10BO3）3晶体生长及其闪烁性能

刘玮 , 潘尚可 , 李焕英 , 蒋勇 , 陈晓峰 , 任国浩

无机材料学报 doi:10.15541/jim20150080

为了提高中子探测效率,以富集10B的H310BO3为原料,通过提拉法生长了富集10B的Ce：Li6Lu(10BO3)3晶体。X射线激发发射光谱测试表明：其发光峰位于360~480 nm,属于Ce3+离子典型的5d -4f跃迁发光,其闪烁发光效率为BGO晶体的3.9倍。在350 nm紫外光和137Cs所发出的662 keV的γ射线激发下测得的衰减时间分别为21.0 ns和31.7 ns,在137Cs辐射源激发下所测得的相对光输出是CsI(Tl)晶体的20%,能量分辨率为9.7%。在慢化252Cf中子源激发下可以观测到明显的中子全能峰,其能量分辨率为33%。上述研究结果表明, Ce：Li6Lu(10BO3)3晶体具有较高的闪烁效率、快的衰减时间和良好的中子探测效率,是一种具有应用前景的中子探测用闪烁晶体。

关键词: Ce:Li6Lu(10BO3)3晶体 , 中子探测 , 提拉法 , 闪烁晶体

Further development of NdFeB magnet industry in China

Yang LUO

材料科学技术（英文）

Due to continued growth in key markets, a broadening of application base and performance improvements, the market demands of NdFeB magnet increased steadily in 1998, and the global output of sintered NdFeB magnet exceeded 10,000 t, in spite of the economic recession in Asia. In 1998 China produced 3,850 t sintered NdFeB block magnet, with an annual growth rate of +22% over the output in 1997.

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Key Problems in Microforming Processes of Microparts

Chunju WANG , Debin SHAN , Bin GUO , Jian ZHOU , Lining SUN

材料科学技术（英文）

From the viewpoint of production engineering, microforming is considered as an effective process to fabricate various microparts. Several key problems in microforming processes were investigated. A new microforming apparatus with a high stiffness piezoelectric actuator as the punch driver was developed to produce microparts. To improve the forming abilities and locate the billets, a floating microdie was designed. The size effects of the billets and die cavities on the microforming abilities were studied with upsetting and coining tests, respectively. And the isothermal microforming process of microgears was performed with the developed microforming apparatus. Several analysis methods were used to evaluate the forming quality of the microparts.

关键词: Microforming , 尺寸效应 , 微塑性成形设备 , 浮动

La对Fe-P-N合金Snoek-Ke-K■ster峰的影响

戢景文 , 魏全金 , 张国福 , 赖祖涵 , 陈廷国

金属学报

研究了F? P—N合金加?对Snoek—Ke-Koster(SKK)峰的影响,发现与合金含La,P的原子浓度比(C_(La)/C_p)有关:对于C_(La)/C_p较大(例如4.56和2.6)的合金,La有明显增强SKK阻?效应:对于C_(La)/C_p=0.27的P过饱和合金,La对SKK峰无明显影响。

关键词: 内耗 , Snoek-Ke-Koster peak , Fe-P-La-N alloy

The present status and key problems of carbon nanotube based polymer composites

Express Polymer Letters

The state-of-art and key problems of carbon nanotube (CNT) based polymer composites (CNT/polymer composites) including CNT/polymer structural composites and CNT/polymer functional composites are reviewed. Based on the results reported up to now, CNTs can be an effective reinforcement for polymer matrices, and the tensile strength and elastic modulus of CNT/polymer composites can reach as high as 3600 MPa and 80 GPa, respectively. CNT/polymer composites are also promising functional composite materials with improved electrical and thermal conductivity, etc. Due to their multi-functional properties, CNT/polymer composites are expected to be used as low weight structural materials, optical devices, thermal interface materials, electric components, electromagnetic absorption materials, etc. However, the full potential of CNT/polymer composites still remains to be realized. A few key problems, such as how to prepare structure-controllable CNTs with high purity and consistently dependable high performance, how to break up entangled or bundled CNTs and then uniformly disperse and align them within a polymer matrix, how to improve the load transfer from matrix to CNT reinforcement, etc, still exist and need to be solved in order to realize the wide applications of these advanced composites.

关键词: polymer composites;carbon nanotubes;mechanical properties;electrical;properties;thermal properties