X. Y. Li
,
X. T. Tian and H. C. Zhu( 1)Weldng Division
,
Beijing Polytechnic University
,
Beijing 100022
,
China 2)National ho. of Advanced Welding Technology
,
HIT
,
Harbin 150001
,
China)
金属学报(英文版)
Mismatching is one of the basic characteristics of welded joints.Overmatched welded joint with a crack in hard weld is simplified as a cracked body of CCP type SHS (a hard bar sandwiched between two soft material with a crier perallel to the interface ) in this paper.Effects of mechanical heterogeneity on fatigue crack growth and crack closure of this model are studied by experimental and elastic - plastic finite element methods. It is found that, residual plastic deformation remaining in the wake of a growing crack tip, which cases crack closure,is affected the plastic deformation in adjacent soft mate- rial near by the crack tip. Both the shape of crack tip plastic zone and stress distribution ahead of crack tip in heterogeneous cracked body are different from that of homogeneous one. Crack closure (open- ing) loads are estimated by investigating the changes of crack tip opening displacement during fatigue loading, and a new model of crack oening process is presented. Because of the difference in the effect of mechanical heterogeneity on displacement of non - fatigue crack and fatigue crack, conventional CTOD can not reflect the real deformation at crack tip of SHS specimens.
关键词:
welded joint
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null
,
null
,
null
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
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正极材料
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Li1+x(Fey/2Niy/2Mn1-y)1-xO2
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离子掺杂
张玉荣
,
陈宇
中国稀土学报
以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1WyP2.9-yO12(以下简称Y-W-Lisicon).X射线粉末衍射分析结果表明,在x＝0.10,y≤0.20及x＝0.20,y≤0.20的组成范围内能得到空间群为R3c,类似于Nasicon的三方结构,但在上述组成范围内均有杂相存在.应用交流阻抗技术测定电导率的结果表明,起始组成为x=0.10,y=0.10的样品在室温下具有较高的离子电导率,为1.65×10-5 S·cm-1;组成为x=0.20,y=0.10的样品在573 K时具有较高的离子电导率,为6.53×10-3 S·cm-1,该样品的分解电压为3.0 V.
关键词:
矿物锂快离子导体
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Y-W-Lisicon
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高岭石
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稀土
陈宇
,
张玉荣
中国稀土学报
以LiTi2(PO4)3为母体,以天然高岭石为起始原料,经高温固相反应制得了一系列新的锂快离子导体Li1.2+x-yYxTi1.9-xAl0.1Si0.1SyP2.9-yO12(以下简称Y-S-Lisicon).X射线粉末衍射分析结果表明在x≤0.3,y＜(0.2+x)的组成范围内均能得到类似于Nasicon三方结构的相,同时还存在其他杂相.应用交流阻抗技术测定电导率的结果表明起始组成为x=0.1,y＝0.15的合成物电导率最高,其在室温下的电导率为2.93×10-5 S·cm-1,在673 K时可达3.62×10-2 S·cm-1,其在473～673 K间的活化能为37.19 kJ·mol-1,分解电压为3.0 V.
关键词:
矿物锂快离子导体
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Y-S-Lisicon
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高岭石
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稀土
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
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上转换
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晶相转变
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锂掺杂
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稀土
张玉荣
,
王文继
功能材料
以LiTi2(PO4)3为基以天然高岭石为起始原料,经高温固相反应(～900℃)制得了一系列新的锂快离子导体材料Li1+2x+ 2yAlxMgyTi2-x-ySixP3-xO1 2(以下简称Ti-Mg-Lisicon).系统的合成温度随x和y值的增大而降低.应用交流阻抗技术测定的电导率数据结果表明x=0.1,y=0.1的合成物的室温电导率最好为1.01×10-4S/cm,而400℃时x=0.1,y=0.3的合成物的电导率最大,为2.53×10-2S/cm.XRD分析结果表明在x=0.1,y≤0.8;x=0.2,y≤0.6的组成范围内均能得到空间群为R3c的合成物.
关键词:
锂快离子导体
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Ti-Mg-Lisicon
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高岭石
Applied Physics Letters
The effect of nonmagnetic Y partial substitution at the Dy site in Dy(1-x)Y(x)MnO(3) up to x=0.2 on magnetism, specific heat, and ferroelectricity is investigated, which resulted in a preliminary multiferroic phase diagram. It is revealed that the Y partial substitution suppresses the Dy-spin ordering point (T(Dy)) and ferroelectric ordering point (T(FE)) but enhances the Mn-spin ordering point (T(N)). The interaction between the spins of Dy and Mn is remarkably affected by Y substitution. The measured electrical polarization depends on the Y substitution in a complex way because the ferroelectricity is sensitive to the interaction between the spins of Dy and Mn. (c) 2011 American Institute of Physics. [doi: 10.1063/1.3536506]
关键词:
ferroelectricity;polarization
陈瑞福
,
王文继
无机材料学报
Li1+2x+yAlxNdyTi2-x-ySixP3-xO12 锂快离子导体（以下简称Al-Nd-Lisicon）可以用精选的天然高岭石Al4[Si4O10]（OH）8为起始原料，经与Li2CO3、TiO2、NH4H2PO4进行高温（800～1000℃）固相反应约20h而制得.一个空间群属于R3c的固溶体导电相可在y=0．5，x≤0.3和y=1.0，x≤0．4的组成范围内发现.该相具有较好的电导性和较低的活化能．起始组成y=1．0,x=0．3的合成物具有最高的电导率，在400℃时；其电导率达到3．08×10-2S／cm，离子导电激活能为35．2kJ／mol.
关键词:
矿物快离子导体
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null
,
null
稀土学报(英文版)
Er(3+) and Li(+) codoped Y(3)Al(5)O(12) (YAG) powders were prepared for a systematic investigation of their upconversion emissions. X-ray diffraction (XRD), upconversion emission spectra, pump power dependence, FT-IR spectra and decay time were studied to characterize the samples. With Li+ doping, the upconversion emission intensity of Er(3+) doped YAG powders was obviously enhanced, accompanied with an increase in the ratio of green to red intensity. The enhancement of emission intensity could be attributed to two mechanisms: one was the distortion of local crystal field around Er(3+), and the other was the decrease in the amount of CO(3)(2-) and OH(-) groups. Our results revealed that the latter was the dominant mechanism of the upconversion intensity enhancement in the YAG:Er(3+)/Li(+) powders.
关键词:
luminescence;optical materials and properties;sol-gel preparation;nanomaterials;rare earths;nanocrystals;nanophosphors;li+
张玉荣
,
王文继
无机材料学报
doi:10.3321/j.issn:1000-324X.2001.01.019
以LiTi2(PO4)3为基以天然高岭石为起始原料，经高温固相反应(9501150C)制得了一系列锂快离子导体材料Li1+2x+yAlxYbyTi2-x-ySixP3-xO12(以下简称Al-Yb-Lisicon). 系统的合成温度随x和y值的增大而降低. 应用交流阻抗技术测定的电导率数据结果表明y=0.3，x=0.1的合成物的电导率最好，400C时电导率达2.4510-2S/cm，200400C内的电导激活能为38.3kJ/mol. XRD分析结果表明在y=0.3，x0.4及y=0.5，x0.3的组成范围内均能得到空间群为R3c的合成物.
关键词:
锂快离子导体
,
Al-Yb-Lisicon
,
高岭石
