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宁立芹%梁德彬%李海刚%毛建英 《宇航材料工艺》2008,38(2):72-75
采用TiZrNiCu非晶态箔状钎料过渡液相(TLP)扩散连接Ti3Al基金属问化合物,通过对接头的力学性能及微观结构的分析,研究了中间层合金TiZrNiCu中Zr元素对Ti3Al基金属间化合物,TLP扩散连接接头组织和性能的影响规律和机理.结果表明,在连接工艺相同条件下,随着中间层合金中添加元素Zr含量减小,Ti3Al基TLP扩散焊接头强度增大;通过延长后续扩散处理时间,可以减小Zr元素对接头组织性能的不利影响. 相似文献
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采用Cu作为中间层实现了Ti53311S合金的TLP连接,通过SEM、EDS方法分析了接头界面的微观组织,研究了接头界面微观组织及力学性能随TLP连接温度及保温时间的变化规律。结果表明:TLP连接接头的典型界面结构为Ti53311S/β-Ti/Ti、Cu(Sn)金属间化合物/β-Ti/Ti53311S。随着TLP连接温度的升高或保温时间的增加,焊缝宽度逐渐增加,Cu元素向母材侧的扩散程度更加充分,化合物相分解消失,接头室温抗拉强度先大幅升高后趋于稳定,连接工艺为980℃/20 min时,接头抗拉强度达到最大值899 MPa。 相似文献
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为了将瞬间液相扩散焊的液相形成过程与固相扩散焊复合,充分利用TLP及固相扩散焊的优点,需要研究接头界面处母材液化规律。选用DD407镍基单晶高温合金作为试验材料,中间层合金采用含B为3.5%的BNi9进行TLP连接,观察母材液化宽度和接头宽度在不同工艺参数下的变化。通过分析得到:母材液化区宽度随着加热温度升高及保温时间增长而增加,在焊接温度为1100℃,保温时间为5min,中间层厚度为150μm的情况下,母材液化的宽度达到65.8μm;中间层厚度对母材液化的影响程度相对较大,主要降熔元素B的总量增加;TLP连接过程中,母材液化的过程为降熔元素B不断向母材中扩散,导致母材液化宽度增加,但随着扩散的进行,B元素的含量逐渐降低引起等温凝固,从而在一定程度上影响了表面清理的效果。 相似文献
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通过SiC颗粒增强Al基复合材料与Al合金的焊接工艺试验研究,重点分析了材料组合,保湿工艺,连接时间等工艺参数对连接接头性能的影响以及连接接头的微观组织及成分分布,研究表明,TLP扩散连接是一种适用于复合材料连接的重要方法,在相同工艺条件下,LF6/SiCp-6061Al的接头性能明显优于LF6/SiCp-2024Al,连接时间过短或过长,都将影响到接头性能,并且连接时间对不同材料组合的影响也不同,采用二次保温工艺可以较大幅度地提高接头性能。 相似文献
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研究脉冲电流辅助瞬间液相(Transient Liquid Phase,TLP)扩散连接技术,采用粉末中间层,利用低压高强脉冲电流通过铝基复合材料搭接面与中间层,从而实现对SiC_p/2024Al复合材料板材的TLP扩散连接。分析不同工艺参数下连接试样的微观组织和力学性能,探索脉冲电流对铝基复合材料连接的影响机理。结果表明:采用真空压强为1×10~(-3)Pa,平均电流密度115 A/mm~2,连接预紧压力为0.5 MPa,连接时间60 min条件下,连接接头形成了良好的冶金连接界面,无缺陷产生;通过对连接接头微观组织观察发现,在脉冲电流作用下,接头原位生成弥散的高强度高硬度金属间化合物增强相,有效地提高了接头的力学性能。 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