聚二醇类淬火介质CH－202的研究

介绍了聚二醇类淬火介质ＣＨ－２０２的合成、主要性能及冷却机理，并简单介绍了该介质在航空铝与钢制零件淬火方面的应用。     

Microstructure evolution of a hypereutectic Nb–Ti–Si–Cr–Al–Hf alloy processed by directional solidification

In this work, the Nb–14Si–24Ti–10Cr–2Al–2Hf–0.1Y alloy(at.%) was processed by the liquid–metal-cooled directional solidification(DS) at 1750 C with withdrawal rates of 1.2, 6,18 mm/min and post heat treatment(HT) at 1450 C for 10 h. The microstructures of the directionally solidified and heat treated samples were investigated. The results show that the microstructure of directionally solidified alloy mainly consists of petaloid Nbss+ Nb5Si3eutectics and Ti-rich Nbss+ Nb5Si3+ Cr2Nb eutectics. With the increase of withdrawal rate, the primary Nb5Si3is eliminated, Nbss+ Nb5Si3eutectic cells turn round and connected with the microstructure refinement and Nbss+ Nb5Si3+ Cr2Nb eutectics turn to a river-like morphology. After heat treatment,Nbss+ Nb5Si3+ Cr2Nb eutectics disappeared and petaloid Nbss+ Nb5Si3eutectics turn to a specific fiber-mesh structure gradually, which is promoted by higher withdrawal rates. Furthermore,both the volume fraction of Cr2Nb and the content of Cr in Nbssof Nbss+ Nb5Si3eutectics change regularly with the increase of withdrawal rate and heat treatment at 1450 C for 10 h.     

Grinding behavior and surface appearance of（TiC_p＋ TiB_w）/Ti-6Al-4V titanium matrix composites

（TiCp＋ TiBw）/Ti-6Al-4V titanium matrix composites（PTMCs） have broad application prospects in the aviation and nuclear field. However, it is a typical difficult-to-cut material due to high hardness of the reinforcements, high strength and low thermal conductivity of Ti-6Al-4V alloy matrix. Grinding experiments with vitrified CBN wheels were conducted to analyze comparatively the grinding performance of PTMCs and Ti-6Al-4V alloy. Grinding force and force ratios, specific grinding energy, grinding temperature, surface roughness, ground surface appearance were discussed. The results show that the normal grinding force and the force ratios of PTMCs are much larger than that of Ti-6Al-4V alloy. Low depth of cut and high workpiece speed are generally beneficial to achieve the precision ground surface for PTMCs. The hard reinforcements of PTMCs are mainly removed in the ductile mode during grinding. However, the removal phenomenon of the reinforcements due to brittle fracture still exists, which contributes to the lower specific grinding energy and grinding temperature of PTMCs than Ti-6Al-4V alloy.     

指点信标结合试飞研究

民用飞机航电系统复杂,试飞科目和架次繁多,为提高试飞效率,结合试飞是一个重要途径。深入研究了指点信标系统和FAA咨询通告(AC)对于指点信标建议的试飞方法,在此基础上,提出了一种新的结合试飞方案——从飞机正常着陆中获取需要的参数作为指点信标符合性分析,相比于独立的指点信标试飞,这样不仅获得的数据量大,试飞效率也更高。     

碳纳米管增强复合材料研究进展

介绍了碳纳米管的结构、性能等特点，综述了碳纳米管在金属基复合材料、聚合物基复合材料和陶瓷基复合材料中的应用研究情况，并对今后碳纳米管复合材料的发展趋势进行了展望。     

鸟撞受损叶片压气机气动性能仿真

基于研究鸟撞现象对压气机气动性能影响的目的，进行单级压气机的气动设计，分析了主要设计参数，并以此为基础，以原型转子叶片为模型进行鸟撞模拟，建立鸟撞损伤叶片模型。在周向上改变损伤叶片的数量生成不同的计算模型，进行全环的数值模拟，考察不同受损叶片数目对压气机气动性能的影响，分析流场细节，总结受损转子气动特性的变化规律。计算结果表明：受损叶片数量分别为1、2、3的压气机转子在设计转速下，气动性能和稳定性都有明显的下降，主要表现为最大效率工况的效率分别减小了1.37%、2.55%、3.57%，压比分别减小了0.19%、0.29%、0.40%，稳定工作的流量范围减小，稳定裕度分别相对减小了14.33%、25.69%、31.97%。     

S弯进气道吞水过程仿真分析

针对配装S弯进气道的发动机在开展台架吞水试验方案设计中缺少输入条件的问题，模拟重建了F-35飞机的S弯进气 道模型，采用数值仿真手段获取了S弯进气道吞水后进气道出口水滴分布图谱。根据工作包线相近的某全尺寸进气道/发动机地 面联合试验结果对所采用的仿真方法进行了可靠性验证，仿真与试验获得的进气道总压恢复系数具有较好的一致性，证明仿真方 法可靠。开展了吞入喷射装置产生的液态水、吞入雨天空气中的液态水2种条件下的进气道吞水仿真，结果表明：S弯进气道吞水 后，在进气道出口形成的水滴分布不同于之前开展的发动机台架吞水试验中所采用的喷水方案，水滴粒子在进气道出口左上角区 域较为集中而不是正下方，在进气道入口前喷水产生的水滴分布图谱比真实雨天工作条件更为恶劣。建议在开展发动机台架吞 水试验前，通过数值仿真或试验测量获取配装进气道后发动机进口的真实水滴分布，以此为输入条件开展喷水方案设计，以便更 好地考核发动机吞水能力。