材料期刊网

EFFECT OF QUENCHING TEMPERATURE ON SHAPE MEMORY EFFECT OF Fe 18Mn 5Si 8Cr 4Ni ALLOY

Y.H.Wen 1) , N.Li 1) , Y.G.Xu 1) , M.J.Tu 1) , P.Q.Li 2) , Y.L.Liu 2) and Y.L.Ma 2) 1) Department of Materials Shaping and Controlling Engineering , Sichuan University , Chengdu 610065 , China 2) Xi'an Petroleum Pipe Research Institute , Xi'an 710065 , China

金属学报(英文版)

The effects of quenching temperature on shape memory effect and microstructure of Fe 18Mn 5Si 8Cr 4Ni shape memory alloy have been studied. The results show that both the shape recovery ratio and the recovery strain increased as quenching temperature increased, the amount of stress induced ε martensite in the process of cold work decreased with the increase of quenching temperature, the shape recovery ratio and the recovery strain reached maximum at 650℃, and then decreased rapidly with the further increase of quenching temperature,the stress induced ε martensite wholly disappeared at 1023K. But when the quenching temperature is higher than 1023K, the further increase of quenching temperature had little effect on shape recovery ratio, the amount and size of thermal induced ε martensite would increased with the further increase in quenching temperature. The shape memory effect can be improved by the moderate amount of pre exist ε martensite in the matrix before deforming.

关键词: shape memory alloy , null , null

强双光子吸收化合物NT-G1和NO-G1合成与性能研究

刘国华 , 杨平 , 蒋宛莉 , 郭晓稚 , 许贵宝 , 蒋雪璋 , 沈梁 , 王筱梅

功能材料

选择氮杂芴(咔唑)为π-中心,分别以三苯胺和噁二唑取代基为"枝",合成了两个强双光子吸收的氮杂芴衍生物-2,8-双(4-三苯胺乙烯基)-N-乙基氮杂芴(简称NT-G1)和2,8-双(2-(4'-乙氧基)-5-(4'-苯乙烯)-1,3,4- 噁二唑)-N-基氮杂芴(简称NO-G1),进行了核磁共振谱和质谱等表征.飞秒钛宝石激光器泵浦下,NT-G1和NO-G1溶液发出强双光子上转换荧光,且后者的双光子荧光发射截面是前者的7倍;双光子荧光法计算出NT-G1和NO-G1双光子吸收截面分别为215GM和454GM.分子构型优化表明,NT-G1分子中心"氮杂芴"所在平面与两端苯环呈螺旋桨式排布;而NO-G1分子共轭长度增大,且中心的"氮杂芴"与两端延伸的"枝"呈平面构型;从结构上看,NO-G1分子属"D-A-π-A-D"型,具有明显的pn结模式,这些都使NO-G1分子具有更好的分子内电荷转移能力,因而有较高的双光子吸收截面.

关键词: 2,8-双(4-三苯胺乙烯基)氮杂芴 , 2,8-双(2-(4'-乙氧基)-5-(4'-苯乙烯)-1,3,4- 噁二唑)-N-乙基氮杂芴 , 双光子吸收 , 双光子荧光

Studies of the Local Structure and the g Factors of the Cu(2+) Site in Y(2)BaCuO(5)

Journal of Superconductivity and Novel Magnetism

The local structure and the g factors (g(x), g(y), and g(z)) of the Cu(2+) site in Y(2)BaCuO(5) are theoretically studied using the perturbation formulas of the g factors for a 3d(9) ion in orthorhombically elongated octahedra. The orthorhombic field parameters in these formulas are determined from the superposition model and the local geometry of the system. From the calculations, the oxygen octahedron is found to undergo the local elongation Delta Z (approximate to 0.05 angstrom) along c-axis and the relative bond length variation Delta X (approximate to 0.1 angstrom) along a- and b-axes, respectively. The calculated g factors based on the above local structure are in good agreement with the experimental data. The relationships between the anisotropies of the g factors and the low symmetrical (orthorhombic) distortions of the Cu(2+) site in Y(2)BaCuO(5) are discussed.

关键词: Crystal fields and spin Hamiltonians;Electron paramagnetic resonance;Cu(2+);Y(2)BaCuO(5);crystal

添加0.1mass%Y的K38G高温合金1000℃恒温氧化行为

于萍 , 王亚权

腐蚀学报（英文）

研究了添加0.1mass%稀土Y的铸造K38G高温合金在1000℃的恒温氧化行为.结果表明,较之不含Y的合金，含Y铸态K38G合金的氧化速率显著降低； 氧化时形成双层的外氧化膜，表层为以Cr2O3和TiO.2为主的混合氧化物层，内层为连续的Al2O3层；没有内氧化和内氮化，没有氧化膜的剥落，加入稀土Y有效地提高了氧化膜的粘附性能.

关键词: 高温氧化 , null , null , null

添加0.1 mass%Y的K38G高温合金1000℃恒温氧化行为

于萍 , 王亚权

腐蚀学报（英文） doi:10.3969/j.issn.1002-6495.2007.03.010

研究了添加0.1 mass%稀土Y的铸造K38G高温合金在1000℃的恒温氧化行为.结果表明,较之不含Y的合金,含Y铸态K38G合金的氧化速率显著降低;氧化时形成双层的外氧化膜,表层为以Cr2O3和TiO2为主的混合氧化物层,内层为连续的Al2O3层;没有内氧化和内氮化,没有氧化膜的剥落,加入稀土Y有效地提高了氧化膜的粘附性能.

关键词: 高温氧化 , K38G , 高温合金 , 稀土元素 , Y

Theoretical explanation of the g factor for Cr4+ in Y2SiO5 crystal

Solid State Communications

The g factor of Cr4-- in Y2SiO5 crystal is calculated from a completed high-order perturbation formula, in which not only the conventional contribution to the g-shift Deltag(= g - g(c)) from the crystal-field mechanism, but also the contribution from the charge-transfer mechanism (which is neglected in the crystal-field theory) are considered. The calculated result shows good agreement with the observed value. It is found that the calculated Deltag due to the charge-transfer mechanism is opposite in sign and about 38% in magnitude, compared with that due to the crystal-field mechanism. So, in the studies of the g factor for a 3d(n) ion having high valence state in crystals, the contribution due to the charge-transfer mechanism should be taken into account. (C) 2004 Elsevier Ltd. All rights reserved.

关键词: insulators;points defects;crystal and ligand fields;electronic states;(localized);electron paramagnetic resonance;atomic screening constants;scf functions;cr4+-y2sio5;transition;pressure

稀土元素Y对K38G高温合金800 ℃恒温氧化行为的影响

于萍 , 王亚权 , 王文

腐蚀学报（英文）

对加入0.05mass%～0.5mass%稀土Y铸造的K38G高温合金800 ℃恒温的氧化行为进行了研究.结果表明,含Y铸态K38G合金的氧化动力学曲线偏离了抛物线规律，接近于立方规律；Y有效抑制了该合金的内氧化；当Y含量达0.5mass%时，该合金中析出富Y相，降低了其氧化抗力.  

关键词: 高温氧化 , null , null

稀土元素Y对K38G高温合金 800℃恒温氧化行为的影响

于萍 , 王亚权 , 王文

腐蚀学报（英文） doi:10.3969/j.issn.1002-6495.2006.03.008

对加入0.05mass%～0.5mass%稀土Y铸造的K38G高温合金800℃恒温的氧化行为进行了研究.结果表明,含Y铸态K38G合金的氧化动力学曲线偏离了抛物线规律,接近于立方规律;Y有效抑制了该合金的内氧化;当Y含量达0.5mass%时,该合金中析出富Y相,降低了其氧化抗力.

关键词: 高温氧化 , K38G高温合金 , 稀土元素 , 钇(Y)

Investigations of the anisotropic g-factors for the Er3+ doped YBa2Cu3Oy (6 < y < 7) superconductor

Materials Science and Engineering B-Solid State Materials for Advanced Technology

The anisotropic g factors g(//) and g(perpendicular to) for the tetragonal Er3+ center associated with Er3+ on y(3+) site in YBa2Cu3Oy(6 < y < 7) superconductor are investigated by using the second-order perturbation formulas of g factors for a 4f(11) ion in tetragonal symmetry. In these formulas, the contributions to the g factors from the second-order perturbation and the admixture of different energy levels are considered. The related crystal field parameters are calculated from the superposition model parameters obtained for similar tetragonal [ErOs](13-) clusters in some zircon compounds. The reasonableness of the results is discussed. (C) 2003 Published by Elsevier B.V.

关键词: electron paramagnetic resonance (EPR);high-T-c superconductor;YBCO;crystal- and ligand-field theory;Er3+;superposition-model;spin probes;epr;la2-xsrxcuo4;esr

Multiferroic phase diagram of Y partially substituted Dy(1-x)Y(x)MnO(3)

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