大直径5A02铝合金薄壁管材生产工艺的研究

采用LD60三辊精密管材轧机对5A02铝合金管坯进行了轧制,利用光学显微镜、硬度计和万能试验机分析了冷加工率、中间退火温度及保温时间对5A02铝合金薄壁管材组织及性能的影响.确定了5A02铝合金溥壁管材在轧制中选择57.2%作为第一道次加工率,在380～410℃时退火保温30～60 min后组织性能较好;轧制后的成品管...     

6A02铝合金薄壁管材退火工艺试验研究

6A02铝合金薄壁管材生产中常存在力学性能不合格问题,对6A02铝合金薄壁管材采用不同的退火温度和退火保温时间进行试验,确定了该种管材合理的退火制度,使其力学性能满足了用户的要求。     

退火处理对5083铝合金组织和性能的影响

研究了退火温度和保温时间对5083铝合金组织与性能的影响。结果表明,冷轧态5083铝合金具有典型的纤维状组织,当退火温度为250℃时,合金保持轧制态的流线组织,仅发生部分再结晶。退火温度升高到300℃时,合金基本完成再结晶。其抗拉强度、屈服强度和伸长率分别为265 MPa、118 MPa和20.5%。     

大直径薄壁5A02铝合金管材旋压生产工艺研究

采用QX63-20卧式强力旋压机对5A02铝合金管坯进行多道次冷旋压,利用光学显微镜、显微硬度计分析旋压过程中大直径5A02铝合金薄壁管材组织性能的变化,并进行不同热处理工艺对其微观组织和力学性能的影响研究。研究结果表明,采用7道次旋压生产工艺可生产出无中间退火的、累积冷旋压减薄率达到80%以上的、表面质量较好、无缺陷的Ф85 mm×2 mm的5A02管材。随着旋压减薄率的增加,原始挤压管坯再结晶态组织逐渐被拉长,纤维组织变得更明显、细小、纤长,管材的显微硬度也由原始的53.3 HV逐渐增加到81.4 HV。将旋压管材在430℃保温60 min热处理后,可以得到组织、性能均满足要求的大直径5A02铝合金管材。     

Ti-Ta系近α型钛合金极薄壁管材退火工艺研究

采用多道次大变形量冷轧加滚珠旋压工艺制备出Ti-Ta系近α型钛合金极薄壁管材,研究了再结晶退火时保温时间和退火温度对管材显微组织与力学性能的影响。结果表明：冷旋态管材呈纤维组织,且纵向相对横向更为明显;退火态管材横纵向均为等轴组织。管材退火时,显微组织与力学性能对保温时间不敏感,保温时间选择范围较宽;随着退火温度的升高,晶粒聚合长大,强度降低,塑性增加。经(620～680)℃/(10～60)min/FC退火后,Ti-Ta系极薄壁管材可满足波纹管成形性能要求。     

Al-Zn-Mg系A合金板材退火工艺制度研究

为了生产符合铁路列车用材性能要求的铝合金板材,试验研究了Al-Zn-Mg系A合金板材的热轧温度,冷轧板材退火温度、保温时间与力学性能、组织之间的关系。确定了该合金板材的热轧温度为370℃~410℃,冷轧板材的退火工艺制度为(370~390)℃保温1 h。     

退火工艺对Fe-36Ni因瓦合金热轧板组织及性能的影响

通过金相显微组织分析及力学性能测试,研究了退火温度(900、950、1 000℃)及退火时间(5、7、9、11 min)对Fe-36Ni因瓦合金热轧板组织及性能的影响,并通过扫描电镜对断口形貌进行了观察。结果表明,随着退火温度的升高和保温时间的延长,奥氏体晶粒逐渐长大,并伴有少量的退火孪晶,材料的塑韧性提高,拉伸时发生典型的韧性断裂。经900℃退火后,其综合力学性能优于其它温度下处理的合金,且合金的晶粒分布比较均匀,并在保温时间为7 min时,具有最佳的综合力学性能。结合现场生产技术要求,退火温度为900℃、保温时间为7 min的热处理工艺最适合Fe-36Ni因瓦合金热轧板的后续轧制生产过程。     

退火温度对TA6合金板材组织和性能的影响

在不同温度下对TA6合金冷轧态板材保温60 min后空冷退火处理,研究退火温度对TA6合金板材组织和性能的影响。结果表明,冷轧后的TA6合金板材,在650℃以下退火时,其组织和性能变化很小;在700℃退火时开始发生再结晶,组织和性能出现明显变化;在720~800℃之间退火时,板材的力学性能已趋于稳定。TA6合金板材合理的退火工艺为(750~800)℃×60 min后空冷。     

3A21铝合金板带材再结晶退火组织性能的研究

试验和讨论了3A21铝合金连续铸轧卷的成分,冷轧变形程度、退火温度与保温时间对该合金板带材再结晶退火后组织与性能的影响规律,提出了一些可获得良好晶粒度和机械性能的控制方法。     

退火工艺对5A02铝合金板材组织与性能的影响

采用单向拉伸试验、金相显微分析和扫描电镜观察等手段,研究了退火工艺对5A02铝合金板材的力学性能、成形性能及显微组织的影响。试验结果表明,随着退火温度的上升、保温时间的延长,5A02铝合金板材抗拉强度略有下降,但是伸长率和应变硬化指数大幅提高。综合比较各种退火工艺后得出,在380℃退火90 min,材料的成形性能较优:抗拉强度为187.89 N/mm2,伸长率达到28.68%,应变硬化指数为0.33,屈强比为0.429。     

Prospects of the Use of Synergetic Approach to Solution of Problems of the Science of Nanomaterials

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. __________ Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 7, pp. 55 – 61, July, 2005.     

Kinetics of the oxidation of metals — Influence of self-diffusion of metal

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.     

胫骨生物陶瓷复合材料的微结构增韧机理

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.     

面向零件形状的计算机图形库的开发

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。     

FeCrAIW电弧喷涂层组织的致密化研究

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.     

Features of formation of the structure in production of blanks of disks of heat-resistant nickel alloys

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.     

Ab-initio calculation of enthalpies of formation of intermetallic compounds and enthalpies of mixing of solid solutions

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.