共查询到20条相似文献,搜索用时 62 毫秒
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采用扫描电镜、能谱仪、万能试验机和电化学工作站等研究了单一稀土(La或Ce)以及混合稀土(La和Ce)的添加对7A04铝合金微观组织与性能的影响。结果表明:在7A04铝合金中添加稀土La和Ce后,沿晶界有块状和棒状的稀土相析出,并使呈连续网状分布的第二相变成断续分布,合金的二次枝晶组织得到细化,其中添加单一稀土Ce对合金的细化效果最好,平均晶粒尺寸为20μm;添加单一稀土La或Ce以及不同比例的混合稀土La和Ce后,7A04铝合金的力学性能和耐腐蚀性能均有所提高,性能由大到小依次为:添加单一稀土Ce、混合稀土La∶Ce=5∶5、单一稀土La、混合稀土La∶Ce=3∶7、混合稀土La∶Ce=7∶3、无稀土,说明单一稀土Ce的添加对7A04铝合金性能改善效果最好,其显微硬度、抗拉强度、伸长率分别为125.4 HV0.5、532.5 MPa和10.8%,相比未添加稀土元素的铝合金,分别提高了72.7%、30.9%和74.2%。 相似文献
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扫描电镜观察显示胫骨是一种由羟基磷灰石和胶原蛋白组成的自然生物陶瓷复合材料.羟基磷灰石具有层状的微结构并且平行于骨的表面排列.观察也显示这些羟基磷灰石层又是由许多羟基磷灰石片所组成,这些羟基磷灰石片具有长而薄的形状,也以平行的方式整齐排列.基于在胫骨中观察到的羟基磷灰石片的微结构特征,通过微结构模型分析及实验,研究了羟基磷灰石片平行排列微结构的最大拔出能.结果表明,羟基磷灰石片长而薄的形状以及平行排列方式增加了其最大拔出能,进而提高了骨的断裂韧性. 相似文献
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论述了CAD技术中参数化设计的三种建模方法,重点介绍了基于特征的参数化建模原理。在此基础上,分析机械设计中的机构结构,归纳出其零件的几何特征构成。设计了机构CAD图形库,并提出了该图形库生成步骤和人机交互界面。 相似文献
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采用激光辐照对FeCrAlW电弧喷涂层的组织进行致密化处理,借助扫描电镜和X衍射对涂层的组织进行了分析.测试了涂层的显微硬度.结果表明:涂层组织致密度提高,孔隙率明显降低.随着激光扫描速度的增加,涂层的显微硬度降低.在较低的扫描速度下,涂层与基体之间形成互熔区,涂层与基体之间产生良好的冶金结合. 相似文献
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V. S. Ivanova 《Metal Science and Heat Treatment》2005,47(7-8):305-311
A synergetic approach to solution of problems of self-controlled synthesis of nanostructures and creation of self-organizing
nanotechnologies is considered in connection with the superproblem of creation of materials with functional properties resembling
those of biosystems.
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Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005. 相似文献
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The importance of the self-diffusion of a metal during its oxidation by a gas is treated for the cases of nonstoichiometric oxides having either interstitial cation or cation vacancies. We have established a general relationship for the reaction rate when a mixed diffusion process occurs. From this relationship, we have shown that the pressure dependence can be different, according to whether the rate-determining process is the self-diffusion through the metal or through the product. 相似文献
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C. Colinet 《Intermetallics》2003,11(11-12):1095
A large number of ab-initio calculations of energies of formation of intermetallic compounds have been performed in the last 15 years. The currently used methods are listed. The paper presents a review of the aluminium based compounds which have been studied. Comparisons of calculated and experimental enthalpies of formation are provided for aluminim-3d and-4d transition metal alloys at equiatomic composition. The modelling of the enthalpies of mixing of solid solutions based on a given lattice is described. 相似文献