T.L. Wang 1
,
2)
,
J.T. Guo 1)
,
D.S. Xia 2)
,
Y.Wang 1) and H.C. Yang 2) 1) Institute of Metal Research
,
Chinese Academy of Science
,
Shenyang 110015
,
China 2) Material and Metallurgical Institute Northeastern University
,
Shenyang 110006
,
China
金属学报(英文版)
Effect of revert cycles on microstructure and fatigue properties of cast cobalt base superalloy K640S has been investigated. The results show that: at 70 times of cool heat cycles, there were microcracks found in seven times revert and ten times revert. With the increasing of thermal fatigue cycles, the crack of revert grows a little faster than virgin. When the cycle time reaches 200, the crack length for both virgin and reverts have been as long as 2mm. The low cycle fatigue life has no remarkable change, with the increase of revert cycles at 815℃, 360MPa ,0 5Hz. With the times of cycles increasing, it is found that the content of impurity and gas in alloy change a little, and there is no obvious change for dendrite microstructure.
关键词:
revert
,
null
,
null
,
null
,
null
齐民华
,
沈琪
,
陈小平
,
翁林红
应用化学
doi:10.3969/j.issn.1000-0518.2003.07.004
无水YCl3与1-环戊烷基茚基锂以1/2的摩尔比在THF中反应合成了二(1-环戊烷基茚基)氯化钇(C5H9C9H6)2Y(μ-Cl)2Li(THF)2,产物用元素分析、红外光谱及XRD进行表征. 结果表明,其晶体属于正交晶系,Pna2(1)空间群,a =1.648 2(7) nm,b =1.877 2(8) nm,c =1.131 7(5) nm,V =3.501(3) nm3,Z=4,Dc=1.285 Mg/m3,最终的偏离因子R=0.068 3,Rw=0.114 3.
关键词:
环戊烷基茚基
,
稀土配合物
,
合成
,
晶体结构
沈保根
,
孔麟书
,
曹蕾
,
王芳卫
,
詹文山
,
郭慧群
,
赵见高
金属学报
用快淬方法制备了单相(Er_(1-x)Sm_x)_2Fe_(17)C_y(x=0.2,<3.0;x=0.5,y<2.0)化合物,研究了它们的形成、结构、稳定性及内禀磁性结果表明,它们在高温是稳定的,随碳含量的增加,晶体结构由六角的Th_2Ni_(17)型向菱方的Th_2Zn_(17)型转变间隙碳原子的引入导致了单胞体积的膨胀、室温饱和磁化强度和Curie温度的增加当y>1.0时,(Er_(1-x)Sm_x)_2Fe_(17)C_y样品在室温均显示出单轴各向异性
关键词:
(Er(1-x)Sm_x)_2Fe_(17)C_y间隙碳化物
,
interstitial carbides
,
magnetic properties
Nabil S. Youssef
,
K.H.Hegab
材料科学技术（英文）
Some transition metal chelates of two ligands L1 and L2 were prepared and characterized by elemental analysis. The IR and 1H NMR spectra of several chelates of two ligands L1 and L2 showed the involvement of the azo group in chelation with the transition metal ions, in most of the studied chelates, and that the two ligands L1 and L2 showed the involvement of the azo group in chelation with the transition metal ions, in most of the studied chelates, and that the two ligands L1 and L2 were coordinated either in the enol or the keto form. IR spetra also showed that Fe(III)-, Ni(II)-, Mn(II)-, VO(II)-L1 and Cu(II)-L2 chelates behaved in a bidentate manner, in contrast with the two (1:1) M:L cobalt chelates with the two ligands are tridentate. TG analysis indicated the presence of three to twelve water molecules of hydration eliminated on heating up to 150°C and one or two coordinated water molecules removed at 150-180°C. The octahedral structure is proposed for all the chelates, except Cu(II)-L2 and Ni(II)-L1 chelates which have square planar geometry, based on their electronic spectra.
关键词:
Journal of Physics and Chemistry of Solids
The layered ternary ceramics Ti3SiC2 and Ti3AlC2 are isostructural and can form Ti3Si1-xAlxC2 solid solutions combining the advanced properties of both compounds [H.B. Zhang, Y.C. Zhou, Y.W. Bao, M.S. Li, Improving the oxidation resistance of Ti3SiC2 by forming a Ti3Si0.90Al0.1C2 solid solution, Acta Mater. 52 (2004) 3631-3637; E.D. Wu, J.Y. Wang, H.B. Zhang, Y.C. Zhou, K. Sun, Y.J. Xue, Neutron diffraction studies of Ti3Si0.9Al0.1C2 compound, Mater. Lett. 59 (2005) 2715-2719; J.Y. Wang, Y.C. Zhou, First-principles study of equilibrium properties and electronic structure of Ti3Si0.75Al0.25C2 solid solution, J. Phys.: Condens. Matter 15 (2003) 5959-5968; Y.C. Zhou, J.X. Chen, J.Y. Wang, Strengthening of Ti3AlC2 by incorporation of Si to form Ti3Al1-xSixC2 solid solutions, Acta. Mater. 54 (2006) 1317-1322]. In the present work, the solid solutions of Ti3Si1-xAlxC2 (x = 0, 0.25, 0.33, 0.5, 0.67, 0.75, 1) are investigated by first-principle calculations based on pseudo-potential plan-wave method within the density functional theory framework. The results show that as Al content increases in the solid solution, all the bonds have weakened to certain extents, which lead to an unstable structure both energetically and geometrically. The calculated results are compared and discussed with the reported data for the Ti3Si1-xAlxC2 solid solutions. (c) 2007 Elsevier Ltd. All rights reserved.
关键词:
ceramics;ab initio calculations;electronic structure;electrical;conductivity;oxidation behavior;mechanical-properties;ti3sic2;temperature;ti3alc2;air;si
Chinese Journal of Organic Chemistry
2,5-Dihydrazino-1,3,4-thiadiazole was prepared by 2,5-dimecapto-1,3,4-thiadiazole and hydrazine, and then the six novel different 2,5-bis(benzylidenehydrazino)-1,3,4-thiadiazole compounds were obtained by a condensation reaction of 2,5-dihydrazino-1,3,4-thiadiazole with substituted benzaldehyde and structurally confirmed by elemental analysis, IR, H-1 NMR and mass spectra. The result indicates that the six 2,5-bis(benzylidenehydrazino)-1,3,4-thiadiazole compounds are of definite inhibition against silver surface in corrosion jet fuel.
关键词:
2,5-dimercapto-1,3,4-thiadiazole;hydrazine;benzaldehyde;aldehyde-hydrazone;synthesis;anti-corrosion;derivatives
杨微微
,
高翔
应用化学
doi:10.3724/SP.J.1095.2011.00625
为了考察取代基团对C60衍生物性质的影响,分别进行了一系列1,2-H(XPhCH2) C60(X=H,o-CH3,m-CH3,p-CH3,o-Br,m-Br,p-Br)的1H NMR、13C NMR和电化学循环伏安测试.结果表明,邻位取代基团对苄基中亚甲基氢原子和碳原子的核磁响应具有较大的影响,而取代基团位置对C60-H和C30sp3碳原子核磁响应影响较小；在循环伏安中,苄基上的-CH3和-Br基团位置对C60衍生物的氧化还原电势并未表现出显著影响,但与1,2-H(PhCH2) C60相比,所有具有CH3PhCH2一基团的化合物氧化还原电势均表现出负移,而具有BrPhCH2-基团的化合物氧化还原电势均表现出正移,表明诱导效应是影响C60衍生物性质的主要因素,因此,可通过调控衍生物的电子结构来探究其性质.
关键词:
富勒烯衍生物
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取代基效应
,
核磁共振
,
循环伏安
王琨
,
康利涛
,
陈石
,
董丽
,
梁伟
,
高峰
无机材料学报
doi:10.3724/SP.J.1077.2014.14026
本工作研究了水热法制备钨系氧化物过程中反应温度对产物物相、微结构和光学性能的影响.XRD结果表明100℃条件下制备的样品为纳米六方相铵钨青铜(NH4)xWO3-y.随着水热温度升高(140和180℃),部分六方相(NH4)xWO3-y逐步转变为正交相三氧化钨WO3·1/3H2O,形成两相共存产物.SEM和TEM分析证实(NH4)xWO3-y和WO3·1/3H2O粒子均为沿[001]方向(c轴)生长的短棒状单晶,随水热反应进行它们会通过取向融并(oriented attachment)方式进一步长大.结构分析同时证实,棒状晶的物相与其尺寸存在明显联系,纳米尺寸的棒状晶为六方(NH4)xWO3-y相,而微米尺寸的棒状晶为正交WO3·1/3H2O相.依据实验结果,提出了一种表面能控制的六方相(NH4)xWO3-y向正交相WO3·1/3H2O相转变机理.光学性能测量表明,100℃制备的六方相(NH4)xWO3-y样品可以很好的遮蔽近红外光(遮蔽率:74.5％),同时保持高可见光透过率(67.6％).
关键词:
(NH4)xWO3-y
,
WO3-x·1/3H2O
,
反应温度
,
近红外光遮蔽性能
