材料期刊网

MICROSTRUCTURE AND PROPERTIES OF CuCr25 ALLOYS WITH DIFFERENT Ni CONTENT

C.Y.Zhang , Y.P.Wang , Z.M.Yang , B.J.Ding , Y.L.Li

金属学报(英文版)

CuCr25 alloys containing different Ni content were prepared by vacuum induction melting(VIM)l.The microstructure and proerties were tested.The results show that with the increase of Ni content in CuCr25 alloys,the Cr phase changed from developed dendrite into nodular grains and was drastically refined;the electrical con-ductivity significantly decrease,but still reach the level of convenlional CuCr50 when the Ni content is below 0.5The Ni content had little influence on their breakdown strength.The first breakdown sites transferred to the boundoary of Cu and Cr phase for CuCr25Ni compared to the Cr phase for CuCr25 without Ni.

关键词: CuCr25 , null , null

RESEARCH ON AS-CAST GRAIN REFINING TECHNOLOGY BY INOCULATING CLEAN STEEL WITH TITANIUM OXIDE

G.G.Cheng , M.L.Wang , X.E.Yang , Y.L.Li , Y.G.Wang , L.Y.Wang , P.Zhao

金属学报(英文版)

Precipitation condition and nucleation of Ti2 03 during solidification of clean steel have been studied. The behavior of Ti2 03 during solidification as well as possibility of using Ti203 to refine as-cast grains as heterogeneous nucleation sites is discussed. It is shown that Ti2 03 can be formed provided that the steelmaking and solidification process is controlled strictly. And inoculating clean steel with Ti203 is an effective way to refine as-cast grains.

关键词: clean steel , null , null

Effect of Li and Ti Additions on L■α(Al)+Mg_2Si Pseudobinary Eutectic Reaction

Shengxu ZHAO , Shunpu LI , Deqian ZHAO , Mingxiang PAN and Xichen CHEN(Institute of Physics , Chinese Academy of Sciences , Beijing 100080 , China)

材料科学技术（英文）

Effect of Li and Ti additions on Lα(AI)+Mg2Si pseudobinary eutectic reaction in ternary Al-Mg-Si system has been investigated by thermoanalysis, directional solidification and metallographic techniques in this study. It has been found that Li addition causes decreasing of the volume fraction of Mg2Si, while a little amount of Ti causes to increasing, which is of a great importance to the adjustment of phase constitution and alloy properties. Doping components have little influence on the eutectic temperature.

关键词:

L12-Al3Li金属间化合物点缺陷浓度的第一原理计算

孙顺平 , 李小平 , 于赟 , 卢雅琳 , 臧冰 , 易丹青 , 江勇

中国有色金属学报

运用第一原理平面波赝势方法计算L12-Al3Li金属间化合物点缺陷的形成焓,并结合Wagner–Schottky模型,研究L12-Al3Li金属间化合物在523、673、823和1000 K时点缺陷浓度与成分之间的关系.结果表明:在这4个温度下,L12-Al3Li金属间化合物中Al空位浓度最小,Li空位浓度次之,Al反位和Li反位的缺陷浓度较大.Al反位和Li反位缺陷浓度在理想金属间化合物Al3Li化学计量比成分处基本相同,不过两种反位的缺陷浓度随着合金成分相对于化学计量比成分的偏离而变化显著,在富Al端Al反位缺陷浓度较大,在富Li端Li反位缺陷浓度较大.运用Arrhenius方程计算点缺陷的有效形成焓,结果显示Al反位和Li反位的有效形成焓较小且基本相同,Li空位次之,Al空位最大.

关键词: Al3Li金属间化合物 , 第一原理计算 , 点缺陷浓度 , 形成焓 , Wagner–Schottky模型

Li+掺杂对Y2SiO5∶Pr3+上转换发光性能影响

刘成 , 杨毅 , 韩正玉 , 武晓雅 , 翁景霞 , 林璐

中国稀土学报 doi:10.11785/S1000-4343.20130408

采用溶胶-凝胶法制备Li+掺杂改性的Y2SiO5:Pr3+上转换发光材料,考察了Li+掺杂对样品晶型及发光性能的影响.采用XRD,DSC-TGA,FS对所制备的材料进行表征,结果表明Li+掺入浓度在7％～ 8％(摩尔分数)之间会引起Y2SiO5晶体类型由X型转变为X2型,且Li+掺入后样品转晶型温度由950℃降至800℃;样品经800℃煅烧处理后以X1型Y2SiO5为主相,850℃煅烧处理后以X2型Y2SiO5为主相;Li+掺入同时会提高Y2SiO5:Pr3+材料的上转换发光强度,Li+最佳掺杂浓度为10％,对于双掺杂pr3+,Li+:Y2SiO5体系中pr3+最佳掺杂浓度为1.2％.

关键词: 溶胶-凝胶法 , 上转换 , 晶相转变 , 锂掺杂 , 稀土

Sm对Mg-l0Y合金组织的细化作用

张清 , 李全安 , 井晓天 , 张兴渊

材料工程 doi:10.3969/j.issn.1001-4381.2011.03.016

Mg24Y5相的细化是进一步提高Mg-l0Y合金力学性能的关键.研究了稀土元素sm对Mg-l0Y合金中的Mg24Y5相及其基体组织的细化作用,结果表明:sm的加人,改善了Mg24Y5相的形貌,促进了细小弥散分布的Mg24Y5颗粒相的形成;同时,Sm的加人,通过固溶作用,进一步细化了基体组织;显微组织的改善导致了合金高温下力学性能的提高.

关键词: Sm , Mg-10Y合金 , 组织细化 , 力学性能

Y 对8090Al-Li 合金拉伸性能和断裂行为的影响

桂全红 , 马禄铭 , 蒋晓军 , 梁国军 , 李依依

材料研究学报

研究了两种不同Y 含量对8090Al-Li 合金拉伸性能及断裂行为的影响。实验表明:加入0.1wt-%Y 可在不降低强度的情况下提高合金的塑性,加入0.5wt-%Y 可在不降低塑性的情况下提高合金的强度。在峰值时效条件下,不加Y 的合金断裂为穿晶韧窝型和沿晶塑性混合方式,并伴有沿晶二次裂纹,加0.1%Y 不改变合金断裂模式,但使沿晶成分减少;加0.5%Y 合金则发生快速剪切断裂。本文从晶粒结构角度对断裂行为提出了解释。

关键词: A—Li 合金 , rare earth element Y , tensile properties , intergranular fracture , transgranular fracture

添加Y对Mg-3.5%Li合金冲击变形行为的影响

沙桂英 , 刘翠云 , 刘腾 , 孙晓光 , 李根

材料工程 doi:10.3969/j.issn.1001-4381.2010.07.014

利用Hopkinson压杆技术对Mg-3.5%Li及Mg-3.5%Li-0.77%Y合金在不同应变率下进行了冲击压缩实验,分析了两种合金的动态应力-应变行为及其应变率效应.结果表明,随应变率提高,Mg-3.5%Li合金的应力-应变行为表现出应变率强化效应与应变率弱化效应的双重特性.添加稀土元素Y后,合金有所强化,但其应力-应变行为仍具有应变率弱化效应,随应变率提高产生的微裂纹引起的内部损伤是导致合金应变率弱化效应的主要原因.

关键词: Mg-Li合金 , Mg-Li-Y合金 , 应变率 , 微裂纹

L1(2)- and L1(0)-like cation-ordered structures in ZrO2-Y2O3 ceramics

Journal of Materials Research

Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y phases, with L1(2-) and L1(0-) like cation-ordered structures, respectively, have been found in ZrO2-Y2O3 ceramics in both the sintered and annealed states. High-resolution electron microscopy, energy-dispersive x-ray spectroscopy and computer simulation have been used to reveal the presence of the phases. The formation of Y0.25Zr0.75O2-x, and Y0.5Zr0.5O2-y phases was initiated during the sintering procedure and developed with the increase in annealing temperature and time. Segregation of yttrium, which was prevalent in different regions even within one grain, induced the formation of Y0.25Zr0.75O2-x and Y0.5Zr0.5O2-y phases.

关键词: yttria-stabilized zirconia;percent y2o3 alloy;x-ray-diffraction;solid-solutions;electron-diffraction;neutron-diffraction;modulated;structure;diffuse-scattering;average structure;tetragonal phase

Li1+x(Fey/2Niy/2Mn1-y)1-xO2正极材料的合成及电化学性能

王秋艳 , 徐连义 , 付煜 , 张艳丽 , 谢嫚

稀有金属材料与工程

采用低温共沉淀-水热-煅烧法合成了锂离子电池Fe-Ni-Mn体系正极材料Li1+x(Fey/2Niy/2Mn1-y)1-xO2,并用XRD、SEM、ICP光谱和电化学性能测试对材料进行了表征.XRD测试和ICP分析表明,Fe、Ni取代Li2MnO3中的部分Mn,形成很好的固溶结构yLiFe1/2Ni1/2O2-(1-y)Li2MnO3 (y=0.l,0.2,0.3,0.4,0.5).SEM测试表明,取代量y不同,材料的表观形貌有所不同,y=0.4时材料的颗粒粒径均匀、较小,呈类球形结构.电化学性能测试表明,当y=0.4时,循环稳定性最好,充放电50次后放电比容量仍可维持在195.0 mAh/g,放电中值电压为3.5 V,y=0.4时样品在大倍率放电下的电化学性能表现良好.

关键词: 锂离子电池 , 正极材料 , Li1+x(Fey/2Niy/2Mn1-y)1-xO2 , 离子掺杂