Author L.J. Chen1
,
2)
,
G. Yao1)
,
Z.G. Wang1) and J.F. Tian1) 1) State Key Laboratory for Fatigue and Fracture of Materials
,
Institute of Metal Research
,
The Chinese Academy of Sciences
,
Shenyang 110015
,
China2) Department of Metallic Material Engineering
,
Shenyang Polytechnic University
,
Shenyang 110021
,
China Manuscript received 18 October 1998
金属学报(英文版)
The cyclic stress response and lowcycle fatigue life for wrought nickelbased superalloy GH4049 were investigated in the temperature range from 500 to 800 The relationship between the strain amplitude and the number of stress reversals was given. The behavior of cyclic hardening was observed for higher strain amplitudes at all testing temperatures and the lowcycle fatigue life generally decreased with increasing testing temperature for the same strain range. In addition, fracture surfaces of the fatigued samples were examined by using a scanning electron microscope.
关键词:
superalloy
,
null
,
null
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
Journal of Alloys and Compounds
The local structures and the EPR g factors of three Ni3+ centers (1)-(3) in LaSrAl1-xNixO4 (LSAN) are theoretically investigated from the perturbation formulas of the g factors for a 3d(7) ion of low spin (S = 1/2) in tetragonally and orthorhombically distorted octahedra. In these formulas, the contributions to the g factors from the low symmetrical parts of the crystal-fields, characterized by the crystal-field parameters D-s, D-t, D-xi and D-eta are taken into account. Based on the studies, it is found that the ligand octahedra are elongated along [0 0 1] axis by about 0.9, 0.7 and 1.0% for centers (1)-(3). The above distortions have a Jahn-Teller nature instead of ordinary lattice deformation, leading to the ligand octahedra less elongated than that (approximate to 1.3%) in the host. Apart from the axial elongation, center (3) suffers additional orthorhombic distortion due to inequivalent variation by about +/- 0.3% of the planar bonding lengths along [10 0] and [0 101 axes, respectively. The calculated g factors show good agreement with the observed values. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
defect structures;electron paramagnetic resonance;crystal-fields and;spin Hamiltonians;Ni3+;LaSrAl1-xNixO4 (LSAN);transition-metal ions;optical-spectra;brillouin-scattering;superposition model;single-crystals;cr3+ ions;srlaalo4;vacancy;epr
王潇
,
戎咏华
,
陈乃录
,
王闯
上海金属
冷轧BN1G不锈钢主要应用在装饰板和家用电器等方面,除了需要满足力学性能要求外,还要求钢板表面光洁度好,不能有表面缺陷,冲压不能断裂.经近二年不等时间的跟踪统计,发现冷轧BN1G钢板的表面质量主要由前期热轧后酸洗引起的氧化皮残留、酸洗花斑、酸洗花纹、色差等缺陷,而机械损伤引起的表面缺陷较少.因此,主要分析了酸洗引起的表面缺陷的起因,并给出了相应解决办法.
关键词:
冷轧BN1G不锈钢板
,
酸洗
,
表面缺陷
史长根
,
王耀华
,
李子全
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2004.02.022
为了研究在不同爆炸焊接工艺条件下获得的复合板的轧制效果,本文对大波、小波、微波状3种界面的1Cr18Ni9Ti/20G复合板进行轧制实验研究.实验表明:只有用下限获得的微小波状界面的爆炸焊接复合板,才能实现成功轧制,而大波状复合板界面存在一定的缝隙、空洞等微观缺陷,在轧制时由于分层会使轧制失效.爆炸焊接+轧制工艺获得的复合板结合界面的组织、强度和性能的测试结果表明:轧制复合板结合界面的剪切和分离强度虽比爆炸态略低,但延伸率、冲击韧性都大大增强,轧制复合板的耐蚀性能也未降低.
关键词:
爆炸焊接
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轧制
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结合界面
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微波状
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小波状
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大波状
International Journal of Modern Physics B
The EPR g factors g(//) and g(perpendicular to) for the six-coordinated Cu2+(1) site in YBa2Cu3O6+x are theoretically investigated from the perturbation formulas for a 3d(9) ion in tetragonally elongated octahedra. The related tetragonal crystal-field parameters Ds and Dt are determined from the superposition model and the structural data for the Cu2+(1) site, by considering the effective elongation of the oxygen octahedron due to the Jahn-Teller effect of the Cu2+ cluster. Based on the calculations, the effective elongation (= 15%) of the ligand octahedron is obtained for the signals at 100K. As for the EPR signals at room temperature, the elongation declines to merely 4%, corresponding to the smaller anisotropy Delta g (=g(//) - g(perpendicular to)). The theoretical results for the g factors are in good agreement with the observed values, and the local tetragonal distortion due to the Jahn-Teller effect is discussed.
关键词:
crystal fields and spin hamiltonians;electron paramagnetic resonance;Cu2+;YBa2Cu3O6+x;single-crystals;yba2cu3o7-delta;evolution;esr
江峰
,
赵康
,
康伟
,
孙军
,
何家文
金属学报
利用奥氏体不锈钢/低碳锅炉钢(1Cr18Ni9Ti/20G)爆炸焊接复合板,通过电子束焊接得到带有界面裂纹的三点弯曲J积分裂纹扩展阻力试样和四点弯曲疲劳试样.分别进行了带界面裂纹双材料和相应单一材料试样的裂纹扩展阻力曲线及其疲劳扩展行为的实验研究.结果表明:双材料界面裂纹的静态和动态扩展阻力均低于裂纹在相应单一材料中的扩展阻力.
关键词:
爆炸层合板
,
null
,
null
胡小强
,
罗兴宏
,
李殿中
材料热处理学报
doi:10.3969/j.issn.1009-6264.2007.z1.002
本文研究了G-X12CrMoWVNbN10 1 1钢在700℃长时间等温处理过程中的组织演变.通过DTA曲线,分析得到该钢种在加热和冷却过程中的各相转变温度.采用光学显微镜、扫描电镜和能谱分析,研究不同时间等温处理后的组织.结果表明:M3C型碳化物优先在原奥氏体晶界附近析出,此后,碳化物聚集长大导致出现两相区.随着等温处理时间的增加,两相区的转变量近似以S形规律增加,基体硬度则线性降低.
关键词:
超超临界钢
,
改进型9Cr1Mo钢
,
组织演变
,
碳化物
,
等温处理
