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1.
Ti—60合金时效处理时初生α相的长大   总被引:4,自引:0,他引:4  
对Ti-5.6Al-4.8Sn-2Zr-1Mo-0.32Si-1Nd(wt%)高温钛合金(简称Ti-60)1010℃/2h-WQ,760℃/2h-AC热处理样品的分析表明,时效处理时,初生α相的晶界向β转变组织内部移动,形成弓出型晶界。淬火状态的相界以一列颗粒形式的残留物显示出来,残留物为富Si-Zr析出物。同时还观察到被残留物阻碍的位错。  相似文献   

2.
碳-碳复合材料Si-MoSi_2涂层的抗氧化性能   总被引:3,自引:0,他引:3  
研究了Si-MoSi2系统作为碳-碳(C/C)复合材料抗氧化涂层的可能性。结果表明,当涂层中MoSi2含量为20(wt)%时,涂层具有优良的抗氧化和抗热震性能,在1500℃下,该涂层表现出长寿命抗氧化性能,242h的氧化失重为0.57%,氧化失重速率稳定在2.43×10-5g/m2.s。  相似文献   

3.
用原位化学气相沉积方法同时沉积铬和硅于30CrMnSiNi2A钢上的研究已获成功。试验表明,理想涂层的试样在自来水、0.5%NaCl水溶液和0.5MH2SO4溶液中都显示了优良的抗蚀性。得到的涂层厚160~200μm,表面成分达到26%~34%Cr、约4%的Si(wt%)。该涂层是用90Cr-10Si(wt%)、中间合金、活化剂(95.5NaF+4.5NaCl)(wt%)和填充料(SiO2)在一定温度下保持若干小时得到的。  相似文献   

4.
一种快速制备C/C材料方法的探索研究   总被引:6,自引:0,他引:6       下载免费PDF全文
介绍了一种新的C/C材料制备方法--快速化学液气相渗透致密法。利用该技术,采用碳毡作预制体,以两种液态低分子有机物作碳源前驱体沉积时间在3h内,沉积温度在900℃ ̄1100℃范围内可获得密度达1.74g/cm^3的C/C材料。碳纤维表面最大沉积速率可达64μm/h,比传统的等温CVI沉积速率(0.1μm/h ̄0.25μm/h)提高了200倍以上,并初步分析了该技术快速致密多孔预制体的机理。  相似文献   

5.
研究了反应铸造TiC/NiAl(Fe)复合材料压缩、拉伸性能和强韧化机制。NiAl(Fe)合金的室温拉伸延伸率达11%。含20%TiC颗粒的NiAl(Fe)基复合材料的室温拉伸率为2.5%。与多晶NiAl合金及其复合材料相比,20%TiC/NiAl(Fe)复合材料的室温拉伸延伸率明显提高。原位合成的TiC增强颗粒在高温下具有明显的增强效果,含20%TiC增强颗粒复合材料的高温强度比基体合金高100%。塑性的枝晶间区域的存在是NiAl(Fe)及其复合材料在室温塑性得以改善的主要机制。XD+RC工艺导致的晶粒细化作用是NiAl(Fe)基复合材料的主要强化机制,位错强化和弥散强化对强度也有一定贡献。  相似文献   

6.
类6013铝合金热处理制度的研究   总被引:5,自引:0,他引:5  
研究了类6013铝合金Al-(0.5%-1.4%)Cu-(0.55-2%)Mg-(0.4-1.4%)Si-(0.35-1.3%)Mn合金铁固溶处理制度、人工时效制度及形变热处理对实验合金强度的影响。实验结果表明;Al-1.4%Cu-0.95%Mg-0.75%Si-0.35%Mn合金与Al-1.4%Cu-2%Mg-1.4%Si-1.3%Mn合金的极限拉伸强度为450MPa,已远超过美国6013合金的  相似文献   

7.
本文对40CrNiMoA的超细化热处理工艺和超塑变形力学行为进行了研究,结果表明,经两次调质加一次亚温淬火和高温回火后,奥氏体晶粒尺寸可细化至6μm,在690℃、ε=4.17×10(-4)S(-1)条件下超塑拉伸,可获得520%延伸率。文中还研究了超塑变形过程中的微观组织变化规律。  相似文献   

8.
研究了Si-MoSi2系统作为碳-碳复合材料抗氧涂层的可能性。结果表明,当涂层中MoSi2含量为20(wt)%时,涂层具有优良的抗氧化和抗热震性能,在1500℃下,该涂层表现出长寿命抗氧化性能,242h的氧化失重为0.57%,氧化失重速率稳定在2.43×10^-5g/ms^2.s。  相似文献   

9.
研究了3-DC/SiC复合材料的氧化行为。在航空发动机燃气环境中的实验结果表明,C/SiC复合材料的氧化失重与材料内部的大量孔隙以及涂层和基体中的微裂纹有关,其中基体内部的孔隙起着主要作用。在燃气中氧化后,C/SiC复合材料力学性能的降低幅度比在干燥空气中的小,这是由于燃气中的氧分压较低。  相似文献   

10.
用透射电子显微镜重点研究了Fe-10Ni-14Co钢的标准处理状态(830℃风冷+—73℃+510℃Sh)的微观组织结构。510℃回火不同时间,由于M2C的析出状态发生变化,钢也由峰时效(510℃/10min)→过时效(510℃/5h)→明显过时效转变。510℃5h合会开始发生逆转变。  相似文献   

11.
有翼高超声速再入飞行器气动设计难点问题   总被引:2,自引:1,他引:2  
杨勇  张辉  郑宏涛 《航空学报》2015,36(1):49-57
有翼高超声速再入飞行器是近年来的研究热点,气动设计是飞行器设计的关键。为了更清楚地认识有翼高超声速再入飞行器气动设计的难点问题,对有翼高超声速再入飞行器的发展、优势及总体任务剖面进行了介绍,从5个方面详细介绍了该类飞行器气动设计的难点问题,包括多约束复杂面对称气动布局设计、高温真实气体效应对气动特性影响、天地差异与天地换算方法、反作用控制系统(RCS)喷流干扰对气动特性的影响以及气动数据不确定度等,简要阐明了这些难点问题对总体设计的重要性以及初步的解决思路,为有翼高超声速再入飞行器气动设计提供了一些参考。  相似文献   

12.
Simulation and Analysis of Crashworthiness of Fuel Tank for Helicopters   总被引:1,自引:0,他引:1  
Crashworthiness requirement of fuel tanks is one of the important requirements in helicopter designs. The relations among the protection frame, textile layer and rubber layer of the fuel tank are introduced. Two appropriate FE models are established, one is for an uncovered helicopter fuel tank without protection frame, and the other is for fuel tank with protection frame. The dynamic responses of the two types of fuel tanks impinging on the ground with velocities of 17.3 m/s are numerically simulated for the purpose of analyzing energy-absorbing capabilities of the textile layer and protection frame. The feasibility of the current crashworthiness design of the fuel tank is examined though comparing the dynamic response behaviors of the two fuel tanks.  相似文献   

13.
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   

14.
范平  范玉青 《航空学报》2008,29(3):707-715
 波音公司面临着来自空客公司的巨大挑战,企业战略性创新才是公司成功的关键。为此波音公司的全部战略性研究集中在扩大产品的差异性上,体现在3个方面:电子化(e-Enabled)运营环境、整体复合材料机身部件的制造技术和支持波音787客机的全球协同环境(GCE)。  相似文献   

15.
临近空间飞行器测控与信息传输系统频段选择   总被引:7,自引:0,他引:7  
柴霖 《航空学报》2008,29(4):1007-1012
 临近空间飞行器是高性能信息化武器平台,测控(TT&;C)与信息传输系统是其信息保障的核心,而选择合理、可行的频段是展开系统设计的前提和基础。频段选择影响到整个技术方案的制定,是一个需综合考虑、影响深远并具有战略意义的关键问题,从国际电联(ITU)国际标准、高速数传、接收信噪比(SNR)、“三抗”、超视距中继、黑障、雨衰以及设备研制成熟度8个方面全面、细致论证了近空间平台测控系统的频段选择问题,最终得出在视距链路中以Ka频段为宜,在超视距链路中以Ku/Ka双频段为宜的结论。  相似文献   

16.
基于弯曲激波压缩系统的高超声速进气道反设计研究进展   总被引:3,自引:0,他引:3  
张堃元 《航空学报》2015,36(1):274-288
总结了近十年来弯曲激波压缩研究的主要成果。提出了弯曲激波压缩系统的新概念,即利用特殊设计的楔形弯曲压缩面或空间弯曲压缩面,产生一系列与前缘弱激波相互交汇或叠加的压缩波系,从而使前缘激波弯曲,形成特殊的弯曲激波,它与波后的等熵压缩波来共同完成对气流的压缩。在此基础上,实现了由给定出口气动参数的超声速内流道反设计,实现了由给定压缩面压力分布和给定压缩面马赫数分布要求的型面反设计,实现了由给定激波波面的压缩型面反设计。研究证明,弯曲压缩面-弯曲激波压缩系统具有良好的综合气动性能,为高性能高超声速进气系统的气动设计提供了一种全新的设计方法。  相似文献   

17.
In order to investigate the effects of fuel injection distribution on the scramjet combustor performance, there are conducted three sets of test on a hydrocarbon fueled direct-connect scramjet test facility. The results of Test A, whose fuel injection is carried out with injectors located on the top-wall and the bottom-wall, show that the fuel injection with an appropriate close-front and centralized distribution would be of much help to optimize combustor performances. The results of Test B, whose fuel injection is performed at the optimal injection locations found in Test A, with a given equivalence ratio and different injection proportions for each injector, show that this injection mode is of little benefit to improve combustor performances. The results of Test C with a circumferential fuel injection distribution displaies the possibility of ameliorating combustor performance. By analyzing the effects of injection location parameters on combustor performances on the base of the data of Test C, it is clear that the injector location has strong coupled influences on combus- tor performances. In addition, an inner-force synthesis specific impulse is used to reduce the errors caused by the disturbance of fuel supply and working state of air heater while assessing combustor performances.  相似文献   

18.
(高)超声速流动试验技术及研究进展   总被引:1,自引:1,他引:1  
易仕和  陈植  朱杨柱  何霖  武宇 《航空学报》2015,36(1):98-119
近年来,与高速飞行器相关的(高)超声速流动受到了极大的关注。这类流动所具有的非定常性、强梯度和可压缩性对试验方法和风洞设计技术提出了挑战。超声速纳米示踪平面激光散射(NPLS)技术是由作者所在团队研发的非接触光学测试技术。它能够以较高的空间分辨率来揭示超声速三维流场的一个瞬态剖面的时间解析的流动结构。介绍了NPLS技术以及基于NPLS开发的密度场测量、雷诺应力测量和气动光学波前测量等方法,并回顾了这些技术在超声速边界层、超声速混合层、超声速压缩拐角、激波/边界层相互作用和光学头罩绕流等流动中的应用,清晰地再现了边界层、混合层、激波等典型流场结构及其时空演化特性。另外,为了模拟和研究高空大气条件下边界层自然转捩和超声速混合层的转捩特性,介绍了高超声速静风洞、超-超混合层风洞的设计技术以及层流化喷管的设计方法。  相似文献   

19.
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   

20.
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