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时效前处理对新型Al-Cu-Li-X合金力学性能和显微组织的影响 总被引:1,自引:0,他引:1
《中国有色金属学报》2015,(12)
研究时效前固溶处理、预变形等对一种新型超高强Al-Cu-Li-X合金板材力学性能和显微组织的影响。结果表明:500~540℃固溶40 min时,随固溶温度的提高,合金的时效强度呈现先升高后持平的趋势,且在520℃时强度略有下降;510℃固溶20~180 min时,随固溶时间延长,合金的时效强度则呈现先升高后降低的趋势;(510℃,40 min)固溶处理后的合金具有最高的时效强度。不同固溶处理合金的强度变化主要受固溶阶段第二相粒子的回溶程度、再结晶晶粒形态及长大趋势和过烧的共同影响。合金强化相为大量T_1相(Al_2CuLi)、部分θ'相(Al_2Cu)和少量S'相(Al_2CuMg),预变形可促进T_1相细小弥散析出,但抑制θ'相及S'相的析出。预变形量小于6%的预变形可有效提高合金的时效强度,但当预变形量大于6%之后,合金强度的增量逐渐减少。 相似文献
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《中国有色金属学报》2016,(2)
利用金相组织观察(OM)、扫描电镜分析(SEM)、透射电镜观察(TEM)以及硬度测试,研究固溶处理对7B04铝合金显微组织及硬度的影响。结果表明:实验合金中的η相(Mg Zn_2)为易溶相,S相(Al_2Cu Mg)为难溶相,含Fe杂质相为不溶相;进行单级固溶处理时,随着固溶温度的升高,实验合金的固溶程度、再结晶程度和再结晶晶粒尺寸增加,当温度超过480℃时,出现过烧现象,力学性能恶化,7B04铝合金淬火敏感性较高;双级固溶可有效抑制合金再结晶、降低合金淬火敏感性,实验条件下较好的双级固溶工艺为(450℃,0.5 h)+(490℃,0.5 h),抑制合金再结晶效果最佳,经120℃时效24 h后,硬度达到最大值,为204HV1。 相似文献
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固溶处理对7150铝合金组织和力学性能的影响 总被引:2,自引:0,他引:2
通过OM、SEM、X射线衍射、DSC差热分析和室温拉伸性能测试,研究固溶处理对7150铝合金挤压板带组织和力学性能的影响。结果表明:合金固溶处理温度越高,时间越长,粗大第二相溶解越多;合金在480℃进行固溶处理时,出现过烧组织,双级固溶处理制度没有提高本合金开始出现过烧组织的温度;随着合金固溶处理时间的延长,组织出现粗化和再结晶的趋势;本合金适合采用475℃,2h的单级固溶制度,经(475℃,2h)+(120℃,24h)固溶-峰时效处理后,合金抗拉强度、屈服强度和伸长率分别为650MPa、600MPa和13.5%。 相似文献
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过时效-重固溶-再时效处理对 7055铝合金组织与性能的影响 总被引:8,自引:1,他引:8
采用拉伸试验、电导率测试及透射电镜观察等方法,研究了重固溶温度和过时效处理时间对7055铝合金组织与性能的影响.结果表明,120℃×3h+180℃×8h过时效处理后,经过不同温度(440℃~490℃)重新固溶处理以及120℃/24h再时效后,7055铝合金的电导率随重固溶温度的上升而降低,但强度升高;延长过时效时间(120℃×3h+180℃×4h~20h),470℃×1h重固溶处理后,合金电导率略微上升,而强度逐渐降低.组织观察表明,过时效处理形成的粗大析出相在不同温度重固溶时的重新溶解程度不同,重固溶温度越低,粗大析出相溶解越不充分,从而形成与回归再时效处理相类似的组织结构;同时,过时效及重固溶处理也有利于Fe、Si和Zr等残留固溶原子以化合物的形式充分析出,因此利用该工艺可以在保持强度不降低的前提下,提高合金的电导率,并最终提高合金的抗应力腐蚀性能. 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