NEPE推进剂/衬层粘接界面细观力学性能/结构研究

研究了不同组成的NEPE推进剂/衬层粘接界面细观力学性能和结构的差异,以及对应粘接界面贮存过程中粘接性能和破坏方式的变化规律,探索了粘接界面的细观力学性能、结构与破坏方式的内在关联,初步提出NEPE推进剂/衬层粘接界面失效模式。试验结果表明,粘接界面细观力学性能、结构与界面粘接质量相关,是影响界面失效模式的主要因素。粘接界面具有高模量、高硬度层,N元素含量高且有明显梯度变化时,粘接质量较好,发生内聚破坏,反之发生界面破坏或混合破坏;老化过程中,粘接界面的模量和硬度降低、N元素的含量明显降低决定粘接界面依次发生内聚破坏、混合破坏和界面破坏。     

整体加筋壁板的破损安全特性与断裂控制分析

用有限元和断裂力学方法分析大型整体机翼下壁板的破损安全特性。对一个九桁条铝合金整体加筋板,裂纹从断裂筋条下向两侧均匀扩展的开裂形式,进行了应力强度因子和剩余强度计算,并和另一个具有相同构形的铆接加筋板的结果进行对比。当裂纹长度在两倍桁条间距以内时两种加筋板的剩余强度水平相当。但是当整体壁板中的裂纹穿过外侧相邻桁条时,整体桁条的止裂能力逐渐减弱。研究对整体壁板蒙皮胶接止裂条的断裂控制措施及有限元建模分析方法,描述止裂条胶层局部脱粘的处理方法和迭代过程。止裂条材料分别选用了钛合金和单向层压复合材料。计算结果说明胶接止裂措施能显著提高整体加筋板的破损安全性能。     

国外固体推进剂及其粘结界面贮存老化研究进展

对国外固体推进剂及其粘结界面贮存老化性能的研究进展和最新研究成果进行了综述。介绍了国外在固体推进剂及其粘结界面老化与监测的情况,展望了该研究领域未来的发展趋势,认为以光谱学和埋入微型传感器等方法为代表的固体推进剂的无损评估技术将是今后研究的重点。     

Investigation of the role of aziridine bonding agents on the aging of the composite solid rocket propellant(CSRP)

The role of bonding agents on the aging characteristics is one of the important research topics.Aging program of the prepared propellant samples was conducting as follows:Five samples,two free of bonding agents,and three containing an aziridine based bonding agents(MAPO,HX-752,MAT4),four samples based on different bonding and curing agents all were aged at 70 ℃.The prepared bonding agent "MAT4" gave remarkable improvements and resulted in highly stable mechanical properties comparing with HX-752 or MAPO.The selected bonding agents family inhibited the rate of decomposition of the propellants during the aging periods and supported the propellant matrix against decomposition at the elevated temperatures.      

补片尺寸对复合材料胶接修理性能的影响

在复合材料胶接修补中，补片的尺寸对胶接强度的影响非常关键。本文针对单面胶接修理结构建立了“三板模型”，并且，通过试验来验证该有限元模型的正确性，然后，利用该模型来分析补片尺寸对胶接质量的影响。对计算结果的分析发现：补片的直径为孔直径的2—3倍，厚度为孔深的45％～60％时，修补结构的强度恢复能达到最大值。     

扩散焊接及其在航空航天领域的应用

扩散焊接是制造航空航天构件非常重要的连接技术。本文简略地介绍了它人特点，分类，连接机理，焊接设备以及它们在航空航天领域的应用。     

因康镍718合金的超塑成形和扩散连接

介绍了用于制造火箭发动机零件的因康镍７１８合金的超塑成形和扩散连接工艺。经特殊加工的细晶粒因康镍７１８合金具有促进的超塑性，历而能用于超塑成形相当复的零件。     

Ti3Al—Nb基合金的焊接性研究进展

介绍了Ti3Al-Nb基金属间化合物合金焊接性的研究状况，重点评述了其物理和焊接冶金特点、主要焊接工艺下的焊接性和焊后热处理对接头显微组织和力学性能的影响，指出了需深入研究的问题。     

Microstructure and Optical Characterization of Magnetron Sputtered NbN Thin Films

Some fundamental studies on the preparation, structure and optical properties of NbN films were carried out. NbN thin films were deposited by DC reactive magnetron sputtering at different N2 partial pressures and different substrate temperatures ranging from –50 ℃ to 600 ℃. X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM) were employed to characterize their phase com- ponents, microstructures, grain sizes and surface morphology. Optical properties inclusive of refractive indexes, extinction coefficients and transmittance of the NbN films under different sputtering conditions were measured. With the increase in the N2 partial pressure, δ-NbN phase structure gets forming and the grain size and lattice constant of the cubic NbN increasing. The deposited NbN film has relatively high values of refractive index and extinction coefficient in the wavelength ranging from 240 nm to 830 nm. Substrate tem- perature exerts notable influences on the microstructure and optical transmittance of the NbN films. The grain sizes of the δ-NbN film remarkably increase with the rise of the substrate temperature, while the transmittance of the films with the same thickness decreases. Ultra-fine granular film with particle size of several nanometers forms when the substrate is cooled to –50 ℃, and a remarkable aug- mentation of transmittance could be noticed under so low a temperature.     

Si3N4陶瓷二次部分瞬间液相连接模型

在Si3N4陶瓷PTLP连接的基础上,提出了Si3N4陶瓷二次PTLP连接中间层设计的一般规律为Ti Cu X(X为Ni,Pt,Au,Pd等),X与Cu在固相和液相均是完全互溶的;分析了陶瓷二次PTLP连接过程并建立了连接模型,阐述了利用该模型选择连接参数的方法。