K. B. Nielsen
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M. R. Jensen and J. Danckert Department of Production
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Aalborg University
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Denmark
金属学报(英文版)
The paper focuses on the combination of the Finite Element simulation and optimization to improve process or product quality. Three different examples to illustrate the developed genetic approach are given. In all three examples is-DYNA3D is used to simulate the process and a general aptimiza- tion sensitivity based strategy is utilized to improve the design. The included examples are: 1) stretch bending of tubes, 2) bulging of tubes, and finally 3) hydromechanical deep drawing. these examples clearly illustrate the potential of systematic optimization in the area of metal processing.
关键词:
finite element method
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null
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null
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null
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null
Materials Letters
Interfacial characteristics of molten Bi-43Sn alloy on amorphous and crystalline Fe(78)B(13)Si(9) during wetting were investigated at 523 K, 573 K, 623 K and 673 K. It is found that an intertnetallic compound exists at the interface of Bi-43Sn alloy on amorphous FC(78)B(13)Si(9), while no intermediate reaction layer is formed at the interface of Bi-43Sn alloy on crystalline Fe(78)B(13)Si(9). For Bi-43Sn alloy/amorphous Fe(78)B(13)Si(9) system, isothermal aging was performed at 323 K, 373 K and 423 K. The layer growth of the intermetallic compound is mainly controlled by a diffusion-controlled mechanism in the temperature range studied because the values of time exponent (n) is approximately equal to 0.5. (c) 2007 Elsevier B. V. All rights reserved.
关键词:
intermetallic compound;amorphous;crystalline;kinetic;diffusion;glass;cu
张承乾
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王继扬
,
胡晓波
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张怀金
人工晶体学报
doi:10.3969/j.issn.1000-985X.2005.05.005
K2Al2B2O7(KABO)晶体是近年发现的一种有应用前景的深紫外非线性光学晶体,也是目前唯一一种可以生长出大尺寸单晶的BO3基团非线性光学晶体.KABO有可能用于固态激光器的266nm及193nm高功率输出.本文对该晶体的物理化学性质及热学性质进行了研究,KABO晶体不潮解,不溶于水、酒精等溶剂,可溶于盐酸,硝酸和磷酸等强酸;测得莫氏硬度为5.5～6.5,用浮力法测得其密度为2.47g/cm3;用差热分析(DTA)方法测量其熔点为1109.7℃.用热重分析(TGA)方法结合分解产物的粉末X射线衍射(XRD)分析,确定KABO在900℃以上开始分解,分解产物主要为KAl11O17和K2Al24O37;用热机械分析仪测量了其热膨胀系数,沿物理学轴X、Y、Z方向分别为8.4×10-6/K、7.7×10-6/K、1.65×10-5/K.在室温至300℃温度范围内测量了KABO晶体的比热变化,比热随温度的升高线性增大.在47.6℃和294.6℃时比热分别为1.0084J/g℃与1.39J/g℃.
关键词:
硼酸铝钾
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热学性质
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非线性光学晶体
Solid State Communications
Temperature dependence of YCo4B compound has been studied by X-ray diffraction method in the temperature range from 78 K to 700 K. Anomalous thermal expansions were observed at about 375 K and 150 K, which correspond to the magnetic order-disorder transition and spin reorientation transition respectively.
关键词:
Fatigue & Fracture of Engineering Materials & Structures
Fatigue crack growth behavior in welded joints subjected to elastic-plastic shock waves was investigated using three-point-bend specimens. The results indicate that the fatigue crack growth rate is reduced in the affected region of elastic or plastic waves. The travel of a plastic stress wave reaches 10 to 13 mm depth, but the hardness in this region is not increased although the lattice distortion is high. The crack path morphologies were observed, and reasons for a decrease in crack growth rate are presented.
关键词:
罗学军
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马国君
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王晓峰
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田高峰
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盖其东
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穆松林
航空材料学报
doi:10.3969/j.issn.1005-5053.2011.4.006
采用热等静压扩散连接工艺实现了FGH95高温合金粉末和K418B铸造合金之间的可靠连接.研究了热等静压复合连接工艺对FGH95-K418B复合界面的成分扩散、界面组织的影响,以及对叶片材料组织和性能的影响.结果表明,通过合理的工艺选择与改进,可以在保证对偶材料性能满足要求的前提下实现界面的良好扩散与结合.
关键词:
双合金
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整体叶盘
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热等静压
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扩散连接
于保正
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汤鑫
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刘发信
机械工程材料
doi:10.3969/j.issn.1000-3738.2003.03.008
研究了不同热等静压工艺对K418B高温合金细晶铸件疏松和晶粒组织的影响.结果表明:对于不同的热等静压设备,由于设备精度和工作尺寸的原因,热等静压真实作用温度会有稍微的差异;铸件铸态晶粒越细,在进行热等静压处理时晶粒越容易长大;在1 185℃以上进行热等静压,铸件内部疏松可以完全闭合,但在1 210℃以上进行热等静压处理时,合金晶粒易于长大.该合金适宜的热等静压工艺制度为1 185～1 200℃/140～160MPa/4h.
关键词:
热等静压
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细晶
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K418B合金
Journal of Magnetism and Magnetic Materials
Easy and hard magnetization curves of YCo4B compound have been measured in the temperature range from 1.5 to 300 K. It was found that the uniaxial magnetic anisotropy field decreases with decreasing temperature, and the magnetic anisotropy changes from the easy c-axis to the easy cone at approximately 150 K. The easy and hard magnetization curves did not cross up to 6 T. High field susceptibility of the compound for magnetic field parallel to the alignment direction seems different from that for a field perpendicular to the alignment direction. A jump was observed along the easy magnetization curve at 1.5 and 77 K. The critical field of the jump is about 1.5 T at 1.5 K and 1.2 T at 77 K. The jump was shown to be reversible at 1.5 K by down hill measurement.
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