搅拌摩擦加工对稀土镁合金组织与性能的影响

制定三种参数对Mg-Nd-Zn-Zr稀土镁合金进行搅拌摩擦加工处理(FSP),通过金相实验观察了合金加工前后的显微组织,发现该工艺在很大程度上细化了合金晶粒;通过拉伸实验测量了合金加工前后的常温及170℃高温力学性能,结果发现合金的力学性能较加工前有明显的提高和改善,且有很好的高温性能。分析表明,合金性能的提高主要源于合金晶粒的细化及FSP加工过程中的沉淀强化作用,而合金晶粒的细化主要是因为在加工过程中合金发生动态再结晶所致,同时合金组织与性能的变化与加工参数也有关。     

铝液在多孔介质中流动的水力模拟测试

本文采用单片微型机辅助测试系统对铝液在多孔介质中渗流的水力模拟流动进行了测试,通过与图像处理结果比较表明该测试稳定性好,灵敏度高,所测结果较真实地反映了流体反重力渗流的流动规律。     

恒温剥蚀对LC4CS铝合金结构和力学性能的影响

研究了恒温剥蚀对ＬＣ４ＣＳ铝合金试样表面宏观形貌及截面微观结构的影响;测定了试样欧姆电阻、力学性能随剥蚀时间的变化。由欧姆电阻值计算所得试样的腐蚀速率,在剥蚀前期快速增大,４ ｈ 后逐渐下降至一定值。金相显微观察结果表明,试样显微结构的变化是力学性能下降的主要原因     

同步辐射貌相术在研究单晶CuZnAl形状记忆合金马氏体相变中的应用

采用同步辐射貌相术跟踪单晶ＣｕＺｎＡｌ形状记忆合金随温度循环而演变的马氏体相变全过程。研究结果表明，该合金的马氏体转变为热弹性的。     

铝锂合金激光焊试验研究

研究国产8090铝锂合金YAG激光焊。试验表明：在合理的焊接工艺参数下可得到优良的焊接接头，接头表面平整、光洁。单面焊能焊厚度不大于0.70mm板，双面焊能焊不大于1.4mm板。金相分析表明接头结合良好、焊缝为细晶组织、焊缝窄，热影响区小，电子探针微区域分析表明焊缝及热影响区成分几乎无变化。8090铝锂合金易产生焊接热裂纹，并易产生延迟裂纹，焊后应进行去应力处理。     

腐蚀环境对LC4CS铝合金疲劳裂纹闭合的影响

采用透射电子显微镜观察了３．５％ＮａＣｌ溶液中的ＬＣ４ＣＳ薄膜试样裂纹扩展，并用俄歇能谱仪对ＬＣ４ＣＳ铝合金边缺口试件在３．５％ＮａＣｌ溶液中腐蚀疲劳裂纹面进行了测试。结果表明，腐蚀介质使薄膜试样理解纹扩展，裂纹面有腐蚀产物生成；腐蚀疲劳裂纹面生成的致密的钝化膜抑制了腐蚀产物的进一步发展，分析认为，３．５％ＮａＣｌ溶液中ＬＣ４ＣＳ铝合金裂纹闭合与干燥空气中相同。     

基于形状记忆合金的仿壁虎柔性脚掌设计

壁虎通过脚掌独特的外翻机制可以迅速地在壁面实现黏附与脱附。本文通过对壁虎脚掌外翻脱附过程的仿生研究,模仿壁虎外翻脱附机理,以形状记忆合金丝为驱动器,设计仿壁虎柔性脚掌,开展力学分析与计算。基于形状记忆合金的驱动特性及仿壁虎机器人的运动步态,设计了仿壁虎柔性脚掌的控制策略。最后分析了脚趾有无外翻动作脱附时的受力情况,实验测试了柔性脚趾的弯曲与外翻脱附性能,验证了仿壁虎柔性脚掌设计的有效性和可行性。     

7715D高温钛合金及其与推进剂的相容性试验

介绍了Ｔｉ－Ｓｎ－Ｚｒ－Ｎｂ－Ｍｏ－Ｓｉ－Ｃｅ系合金７７１５Ｄ高温钛合金的研制过程。７７１５Ｄ分别在Ｎ２Ｏ４及甲基肼液体中进行的浸蚀２２３２ｈ的相容性试验。结果在Ｎ２Ｏ４及甲基肼中的腐蚀速率分别为４×１０－４ｍｍ／ａ及１×１０－４ｍｍ／ａ，均优于航天工业总公司的一级相容性标准。由７７１５Ｄ高温钛合金制作的ＤＦＨ－３大型广播通信卫星的远地点发动机已通过多台次的地面试车和长程高空模拟试牢，其中两台长程高空模拟试车均超过１８０００ｓ，发动机设计研制单位结论为７７１５Ｄ钛合金能满足该发动机地面试车及长程高空模拟试车的要求     

Metallic and Oxidized Aluminum Debris Impacting the Trailing Edge of the Long Duration Exposure Facility (LDEF)

A total of 87 microcraters >30 m in diameter that were found in gold substrates exposed on the trailing edge of the non-spinning Long Duration Exposure Facility (LDEF) yielded analyzable projectile residues in their interiors. Using qualitative SEM-EDS analysis methods, some 60 of these craters were formed by natural cosmic-dust particles, while 27 residues (31%) were assigned to orbital debris (Hörz et al., 1993). The far majority of the orbital-debris impacts, 24 (89%) of the 27 events, contained only aluminum in their X-ray spectra. The present study evaluates these aluminum-rich residues in detail and employs a windowless X-ray detector, which permits for the analysis of low-Z elements and specifically of oxygen. This makes it possible to discriminate between oxidized (Al₂O₃) and metallic (Al) projectiles from dramatically different sources, the former produced during solid-fuel rocket firings, the latter resulting from explosively or collisionally disrupted spacecraft.Of the 24 craters analyzed with the windowless detector, 13 (54%) contained Al₂O₃ and 11 (46%) yielded structurally disintegrated Al metal. The oxidized residues preferentially occur in the smaller craters, all <60 m in diameter. Corresponding particles on LDEF's trailing edge are <35 m in diameter. Some 70% of this particle population is composed of Al₂O₃. Although solid-fuel rocket exhaust products are typically <5 m in size, they tend to coagulate into crusts at the rocket nozzle to be shed occasionally as relatively large, aggregate particles. Structurally disintegrated, metallic fragments compose one-third of all particles <35 m, but they dominate all particles >35 m, and thus all craters >60 m. These findings clearly establish that solid-rocket exhaust particles, as well as explosively or collisionally produced debris, exist in low-inclination, high-eccentricity orbits in sufficient quantities that they must be accounted for in models describing the present and future orbital-debris population at typical Shuttle and Space Station altitudes.     

超细铝粉的燃烧特性及燃烧模型

运用ＤＴＡ－ＴＧ、ＰＤＳＣ单幅近距摄影、扫描电镜、推进剂爆热的测定等多种实验技术，对超细铝粉燃烧特性及其燃烧模型进行了研究。结果表明，在中压区，推进剂燃面的ＳＡ１直接点火燃烧放热，提高了推进剂燃速，并提出了ＳＡ１在推进剂燃面上直接点火的观战及燃面点火的两个条件；揭示了铝粉在中、高压区内的不同作用，提出了铝焰的概念；绘制了铝和ＳＡ１的燃烧行为图。