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对GH4169合金开展不同变形量的冷轧和热处理实验,分析不同冷轧变形量和随后的不同热处理状态对板材显微组织及硬度的影响。不同冷轧变形量研究结果表明:随着变形量的增加,冷轧板材中的位错密度升高并形成滑移带,织构组织逐渐增强,退火孪晶界逐渐消失,板材硬度随之增大。不同热处理状态研究分析表明:980℃×10 min固溶处理后,变形量小于20%时,板材中仍残留有变形晶粒和位错,随着变形量增加再结晶逐渐发生,晶粒度尺寸逐渐细化,板材硬度随变形量的增加而升高;变形量达到25%以上时,固溶态板材可完成再结晶,变形晶粒和冷作硬化基本消除,板材的硬度降低至未变形的水平并且不随变形量增加而改变;时效热处理后板材中析出γ’’和γ’强化相,板材硬度显著高于冷轧态和固溶处理态且硬度基本不受冷轧变形量的影响;GH4169合金在980℃下固溶处理而发生再结晶的冷轧变形量门槛值处于5%~10%范围内,完全再结晶的冷轧变形量门槛值为25%左右。综合考虑实际生产情况,GH4169合金板材优化的制备工艺为冷轧变形量大于25%,相应的固溶处理制度宜选择为980℃×10 min。 相似文献
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朱大鹏%尹志民%滕浩%潘青林 《宇航材料工艺》2004,34(6):45-49
研究了添加微量Sc和Zr对系列Al-Mg-Mn合金显微组织和拉伸性能的影响。结果表明:微量Sc和Zr添加到Al-Mg-Mn合金中,热轧态合金的拉伸强度和屈服强度分别提高了75MPa-90MPa和90MPa-94MPa;经冷轧后340℃/1h稳定化退火,合金拉伸强度和屈服强度分别增加了85MPa-95MPa和90MPa。100MPa,而延伸率仍保持在11%-12%;并能显著细化合金的铸态晶粒,强烈抑制合金的热轧态和板材冷轧后退火过程中的再结晶,晶粒组织成纤维状;使合金强化的机制为晶粒细化强化、亚结构强化和铝钪锆化合物粒子引起的析出强化。 相似文献
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研究了拉拔态CP(Commercially Pure)钛不同加热温度下的组织演变,确定了再结晶温度。结果表明:在保温20min的条件下,当加热温度为550~600℃时内部组织发生回复;加热温度为600℃时开始出现再结晶组织;达到650℃时发生完全再结晶,晶粒呈等轴状,大小为2~5μm,抗拉强度为525MPa。研究了保温时间对内部组织的影响,当不进行保温时,在650℃温度下不能使材料发生完全再结晶;当保温时间为20min时,材料发生完全再结晶且组织状态良好;在650℃下保温时间达到1h,材料组织粗大。冷却方式对显微硬度的影响较小,对晶粒度有一定影响,当加热温度为600~650℃时,水冷方式晶粒细小,当加热温度小于600℃或大于700℃,冷却方式对晶粒度影响较小。 相似文献
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基于飞机油箱模型形状特征油量测量切片步长选择方法研究 总被引:1,自引:0,他引:1
在分析飞机数字式油量测量过程中目前广泛使用的切片法油量测量原理的基础上,针对现有的定步长切片法无法得到准确、可靠的燃油质量特性数据库的缺陷,结合对飞机油箱模型形状特征的分析,提出了基于飞机油箱模型形状特征的油量测量切片步长选择方法。此方法包括切片步长整体和局部选择两个过程,整体选择以实现相邻两切片平面所夹油箱模型体积近似相等为目的来确定切片步长,以体现油箱模型截面整体变化规律;局部选择以设计切片平面与截面突变平面重合或尽可能接近的方式,突出油箱截面的局部变化特征。实验结果表明:该切片步长选择方法较定步长方法能够建立更为合理、可靠的燃油质量特性数据库,从而提高了油量测量精度。 相似文献
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The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow 总被引:1,自引:0,他引:1
This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig.Measurements of heat transfer from the discs and tangential velocities are presented.The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine.Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air.Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows(Re up to 5×106 and Rez up to 2×105).Two different builds have been tested.The most significant difference between these two build configurations is the size of the annular gap between the(non-rotating) drive shaft and the bores of the discs.The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method.The velocity measurements were made using a two component,LDA system.The heat transfer results from the discs show differences between the two builds.This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity.There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig.For the narrow annular gap,there is an increase of non-dimensional tangential velocity V/Ωr with radial location to solid body rotation V/Ωr=1.For the wider annular gap,the non-dimensional velocities show a decrease with radial location to solid body rotation. 相似文献
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Abnormal Shape Mould Winding 总被引:1,自引:0,他引:1
Fu Hongya Wang Xianfeng Han Zhenyu Fu Yunzhong 《中国航空学报》2007,20(6):552-558
为解决网格化芯模的缠绕问题,本文提出了复合材料面片缠绕机理;接着详细分析了面片缠绕过程中的芯模凹曲面上纤维滑线和架空现象,应用微分几何曲面理论和空间几何理论,提出判据及其解决方案;最后,针对飞机发动机进气道的缠绕成型,编制缠绕控制程序并进行相应的实验,验证了面片缠绕方法的可行性。 相似文献
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航天器返回地球的气动特性综述 总被引:4,自引:0,他引:4
航天器返回地球的飞行过程中,气动特性是实现将宇宙飞行速度减到落地前速度、保证再入飞行得到有效控制以及再入防热安全可靠的关键因素。针对简单旋成体气动外形、半弹道式再入控制、烧蚀防热类返回航天器,综述了返回地球过程中变化的空气流域特性、航天器周围的气体绕流环境、空气与航天器作用产生的动力学与热效应等。系统地给出了该类航天器的再入气动特性参数与飞行性能的共性规律,包括:气动阻力与再入减速、气动升力与再入轨迹控制、配平攻角与飞行稳定性、气动加热与防热,以及再入过程中不同气动特性航天器、气象条件变化等对再入飞行性能的影响规律。为航天器开展返回飞行过程的跨流域气动性能工程研制提供设计参考。 相似文献
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Research on Auto-detection for Remainder Particles of Aerospace Relay Based on Wavelet Analysis 总被引:2,自引:0,他引:2
GAO Hong-liang ZHANG Hui WANG Shu-juan 《中国航空学报》2007,20(1):75-80
Aerospace relay is one kind of electronic components which is used widely in national defense system and aerospace system. The existence of remainder particles induces the reliability declining, which has become a severe problem in the development of aerospace relay. Traditional particle impact noise detection (PIND) method for remainder detection is ineffective for small particles, due to its low precision and involvement of subjective factors. An auto-detection method for PIND output signals is proposed in this paper, which is based on direct wavelet de-noising (DWD), cross-correlation analysis (CCA) and homo-filtering (HF), the method enhances the affectiv-ity of PIND test about the small particles. In the end, some practical PIND output signals are analysed, and the validity of this new method is proved. 相似文献
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Effects of Mo on the Microstructure and Hydrogen Sorption Properties of Ti-Mo Getters 总被引:1,自引:0,他引:1
ZHOU Hong-guo WEI Xiu-ying MAO Chang-hui XIONG Yu-hua QIN Guang-rong 《中国航空学报》2007,20(2):172-176
The effects of Mo on the microstructure evolution, porosity and hydrogen sorption properties of Ti-Mo getters are investigated in this work. The results show that the addition of Mo prolongs the densification process of Ti-Mo getters and results in a significant amount of sintered pores. With the Mo content increasing, the porosity of getters firstly increases reaching the maximum value as it at- tains about 7.5wt.%, and then drops. At the room temperature, the hydrogen sorption property of getters increases progressively with the Mo content increasing, but the tendency is not very clear before its content lies below 2.5wt.%. When the Mo content achieves about 7.5wt.%, the hydrogen sorption property proves to be the best. The discussion is made about the above mentioned phenomena inclusive of hydrogen sorption properties of getters under different activation conditions (from 500-750 ℃). 相似文献
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YANG Fen ZHANG Xue-jun TIAN Fang WU Xu GAN Fu-xing 《中国航空学报》2007,20(2):181-186
Antimony-doped tin hydroxide colloid precipitates have been synthesized by hydrolysis of SnCl4 and SbCl3 using: (1) an ion-exchange hydrolysis to remove chlorine ions, and (2) isoamyl acetate as an azeotropic solvent to obviate water. The obtained dried powder is of high dispersivity without any need for further grinding. The size and dispersivity of the final particles are investigated with the aid of TG-DTA, BET, XRD and TEM. After having calcined, the antimony-doped tin oxide nanopowder possesses a tetragonal rutile structure with high dispersivity, uniform particles and low hard agglomeration. 相似文献