共查询到20条相似文献,搜索用时 78 毫秒
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采用传统铸渗工艺研究了工艺因素对表面复合铸渗层质量的影响,结果表明:适当的浇注温度有利于形成高质量的表面复合铸渗层,小型铸钢件的适宜浇注温度为1 650℃;要形成与基体结合良好的复合铸渗层,需有合适的涂层厚度,试验条件下,涂层厚度为5 mm时的复合铸渗层质量较好;涂层位于铸型侧面较位于铸型底部易于形成高质量的表面复合铸渗层。 相似文献
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研究了不同铸渗工艺对铸钢件表面铸渗硅复合层厚度和质量的影响。采用扫描电子显微镜(SEM)、X射线能谱(EDS)及显微硬度仪等分析手段,阐述了该铸钢件表面铸渗硅复合层的微观成分、组织及性能特点。结果表明,钢水的浇注温度为1580℃左右时,铸钢件表面可以得到厚度为0.6~2.8mm并且表面质量较好的铸渗硅复合层。另外渗硅层与母材铸钢的界面为机械结合状态。 相似文献
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研究了不同铸渗工艺对铸钢件表面铸渗硅复合层厚度和质量的影响。采用扫描电子显微镜(SEM)、X射线能谱(EDS)及显微硬度仪等分析手段,阐述了该铸钢件表面铸渗硅复合层的微观成分、组织及性能特点。结果表明,钢水的浇注温度为1580℃左右时,铸钢件表面可以得到厚度为0.6-2.8mm并且表面质量较好的铸渗硅复合层。另外渗硅层与母材铸钢的界面为机械结合状态。 相似文献
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介绍了铸渗工艺的发展及机理,分析了铸渗外层组织、中层组织、内层组织的形成原因,指出:(1)铸渗层组织由表层的合金烧结层、内层的钎焊层、界面的熔合层三个区域构成;(2)浇注温度对复合层的质量有显著的影响,当浇注温度在1 540~1 580℃、增强颗粒的粒度在60~80目之间时,复合层的综合质量较为理想;(3)由于铸渗层存在(Fe,Cr)7C3、Cr7C3、WC等组织,耐磨性能大大提高;(4)从复合层到基体显微硬度呈梯度分布,显微硬度值先升高后降低,硬度的梯度分布使复合层的强度与基材的韧性得到充分的利用。 相似文献
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介绍了采用消失模铸渗技术制备铁基表面复合材料的研究现状,列举出影响铸渗效果的几项关键因素,对增强体颗粒的选择、涂料添加剂的选择以及浇注温度的确定进行了分析总结,并指出影响铸渗质量的重要因素是表面复合层与基体的结合界面强弱。对消失模铸渗法制备表面复合材料的研究前景进行了展望。 相似文献
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刘炳 《特种铸造及有色合金》2007,27(1):14-15
研究了不同铸渗工艺对铸钢件表面铸渗硅复合层厚度和质量的影响。采用扫描电子显微镜(SEM)、X射线能谱(EDS)及显微硬度仪等分析手段,阐述了该铸钢件表面铸渗硅复合层的微观成分、组织及性能特点。结果表明,钢水的浇注温度为1560℃左右时,铸钢件表面可以得到厚度为0·5~3·3mm且表面质量较好的复合层。另外渗硅层与母材铸钢的界面为结合牢固的锯齿型冶金结合状态。 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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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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Simich-Lafitskii N. D. Koldaev A. V. Kraposhin V. S. Zaitsev A. I. Talis A. L. 《Metal Science and Heat Treatment》2020,61(11-12):675-680
Metal Science and Heat Treatment - The problem of formation of properties in microalloyed sheet steels is considered. The cause and the possible mechanism of precipitation of carbides of refractory... 相似文献
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《全面腐蚀控制》2015,(4)
NOx是大气环境的主要污染物之一,其主要来源为火力发电机组。依靠低氮燃烧技术,远达不到排放要求。选择性催化还原脱硝(简称SCR)技术是目前效率最高、最成熟、应用最广泛的电厂烟气脱硝技术。目前,在线氨逃逸监测技术存在诸多问题,影响了氨逃逸监测数据的准确度和稳定性。在燃料种类、炉膛结构、受热面布置、过量空气量、炉膛气流分布以及脱硝催化剂类型等条件确定的情况下,控制好氨加入量及其逃逸量是保证NOx脱除率的关键所在。燃煤锅炉除尘飞灰氨含量可侧面反映脱硝氨逃逸率的状况。根据国外的文献报道,正常情况下,电除尘灰中氨含量一般在50mg/kg-100mg/kg范围内。由于国内尚无灰中氨含量的测定方法,亦无脱硝运行对飞灰含氨量影响的数据积累。本文通过大量试验,确定了灰中氨溶解条件(如溶解时间、搅拌状态、灰水比、灰样量及其稳定性等),制定了灰中氨含量测定方法。 相似文献
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O. N. Vlasova N. N. Korneeva V. I. Eremenko O. Kh. Fatkullin N. M. Semenova S. N. Petrova D. D. Vaulin 《Metal Science and Heat Treatment》1991,33(12):924-931
Conclusions To provide a high level of mechanical properties in wrought blanks of cast ÉP741NP and ÉP962 alloys it is necessary to form controlled structures. A necklace-type structure formed in homogenizing isostatic treatment, subsequent thermomechanical working including alternation of the operations of deformation in the (+)-area and recrystallization anneals, and final heat treatment is preferable. The temperature conditions of all stages of thermomechanical working are strictly controlled, especially the final operation of deformation and heating for hardening. To eliminate hardening cracks and distortions it is necessary to use molten salts at t=600°C as quenchants. The use of multiple production operations makes it possible to significantly reduce the structural inhomogeneity related to inhertance of the original dendritic structure. However, the structure of the final semifinished product is nevertheless characterized by a difference in occurrence of the processes of polygonization and recrystallization between the former dendritic cells and the interdendritic spaces in deformation and heat treatment.To obtain structurally homogeneous blanks for gas turbine engine parts it is necessary to use basically new methods of remelting such as vacuum double electrode remelting and electron beam remelting with an intermediate vessel.Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 25–29, December, 1991. 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