保温时间对Ti-28Ni钎料钎焊连接Ti60/高铌TiAl合金接头的影响研究

在钎焊温度1 080℃、保温时间0~15min条件下,用Ti-28Ni钎料对Ti60与高铌TiAl合金钎焊连接进行了研究。用SEM,EDS等方法对接头微观组织进行分析,并研究了保温时间对接头连接界面微观组织和力学性能的影响。结果表明:获得的接头无气孔和热裂纹,接头的典型界面结构为Ti60/α+(α+β)/Ti_2Ni+(α+B2)/α+Ti_3Al/Ti_3Al/B2/高铌TiAl合金;当保温时间较短时,断裂发生在钎缝处,钎缝区含大量Ti_2Ni相,随着保温时间的延长,Ti_2Ni相逐渐消失,α+Ti_3Al网状区面积不断增大且向Ti60合金侧偏移,保温时间过长时,接头断裂位置由钎缝区向高铌TiAl合金母材侧偏移,断裂形式为脆性断裂。保温时间10min时,接头平均剪切强度达到最大值139 MPa。     

钛合金夹层结构扩散钎焊工艺研究

利用Dictra动力学软件对中间层Cu元素在TC4钛合金扩散钎焊界面附近的浓度分布规律进行了模拟研究,获得了中间层厚度、连接温度和保温时间对界面元素扩散距离的影响趋势,结合夹层结构零件的焊接试验,验证了扩散模拟计算的正确性。结果表明,连接温度对钛合金夹层结构扩散钎焊的接头强度影响最大,其次为保温时间,中间层厚度对接头强度无显著影响。针对钛合金夹层结构零件,结合焊缝微观组织分析可知,较优的扩散钎焊工艺参数应为:连接温度940℃,保温时间50 min,中间层厚度为20μm,达到了产品的使用要求。     

TiAl基合金和42CrMo钢的真空钎焊

采用Ti基快速凝固钎料对TiAl基合金和42CrMo钢的真空钎焊进行研究,对分别在三种工艺条件下获得的接头性能进行了比较。通过扫描电镜和X射线衍射对接头组织进行了分析,确定了快速凝固钎料在界面层中的生成相。     

卫星钛导管安装位置感应钎焊试验

针对目前我国安装位置卫星钛导管氩弧焊存在的导管装配精度要求高、焊接周期长,接头焊缝凹陷严重等问题,在远离高频加热装置7米处,进行了模拟卫星安装位置的φ6×1mm钛导管氩气保护感应钎焊试验。试验时使用了可分式钎焊钳和70Ti—15Cu—15Ni钎料。从感应钎焊的钛导管接头的拉伸强度,液压,检漏和振动等试验结果来看,该工艺有可能替代我们目前使用的不添加焊丝的全位置氩弧焊连接工艺。     

Si3N4/TC4活性钎焊连接机理与性能

针对Si_3N_4/TC4复合结构钎焊连接问题,研究了钎料和母材中活性元素Ti对Si_3N_4/TC4接头润湿性、界面结合机制和力学性能的影响。进行了润湿、接头显微组织分析和剪切强度试验,结果表明:活性元素Ti对于钎料在陶瓷表面的润湿起主要作用,Ag-Cu钎料通过TC4母材中Ti元素的长程扩散进入Si_3N_4界面虽然实现润湿,但形成的反应产物并不明显,陶瓷/钎料界面成为断裂薄弱区域。Ag-Cu-Ti钎料中Ti元素在Si_3N_4一侧界面富集形成TiN+Ti_5Si_3反应层,对钎料在陶瓷界面润湿性和接头断裂脆性都具有改善作用,接头剪切强度达到267.3 MPa。     

固体火箭发动机粘接界面湿热老化与寿命评估

通过对固体火箭发动机衬层-推进剂粘接界面的湿热加速老化试验以及不同老化时间下粘接界面的扯离强度测量,分析了不同湿热老化条件下试验件扯离强度随老化时间的变化规律。综合运用Eyring模型与Arrhenius模型,建立了粘接界面湿热老化寿命模型,预测了正常贮存条件下发动机的贮存寿命。研究结果表明,粘接界面平均扯离强度随老化时间呈下降趋势,中间有一个强度趋于稳定的平台期;在温度为20℃,湿度为65%RH条件下,粘接界面的强度半衰期寿命为12.8 a。     

某单室双推力发动机串联装药固体推进剂界面力学性能分析

为解决某单室双推力发动机串联装药两级固体推进剂界面力学性能差的问题,通过热力学理论计算,采用优选燃速调节剂,优化匹配两级推进剂的固体物级配、键合剂组合、增塑比、固化参数(NCO/OH摩尔比或R)等方法优化推进剂配方,对试样进行力学性能测试,并分析了各助剂对推进剂界面力学性能的影响。结果表明,在70℃,拉伸速率2 mm/min条件下,抗拉强度σ_m≥0.6 MPa,最大延伸率ε_m≥45%;在-50℃,拉伸速率100 mm/min条件下,σ_m≥3.0 MPa,ε_m≥45%。所研制的高固含量、高能量密度两级推进剂的界面力学性能优良,解决了单室双推力发动机现有串联装填药型、能量和燃速不同的推进剂界面力学性能偏低的问题。     

固体推进剂宽温-气体围压试验系统设计与试验

针对固体推进剂常压条件下力学性能满足要求,而发动机药柱结构完整性破坏频发的难题,研制了固体推进剂宽温-气体围压试验系统,对某HTPB推进剂进行了不同环境压力、温度和拉伸速率下的定速拉伸试验,获得了环境压力、温度和拉伸速率对推进剂应力-应变曲线的影响规律。研究表明,围压环境下推进剂应力-应变曲线没有明显的"脱湿"点,推进剂的抗拉强度明显提高;快速拉伸条件下,围压环境极大地降低了推进剂的延伸率,23℃常温8 MPa围压环境1000mm/min拉伸速率条件下推进剂最大延伸率相对常压条件降低45%;低温围压快速拉伸条件下推进剂的力学性能最为恶劣,-50℃低温8 MPa围压环境500 mm/min拉伸速率条件下推进剂最大延伸率降至11%。相关方法和结论可为固体发动机精细结构完整性分析和贮存寿命预估提供参考。     

铜及铜合金真空扩散焊接工艺优化及接头组织性能分析

采用真空扩散焊接技术进行了铜及铜合金焊接工艺试验,研究了焊接温度、保温时间、焊接压力、镀层(Ni)对接头界面组织及性能的影响,并测量分析了接头金相、力学性能与显微硬度。结果表明:通过镀镍有效消除了零件表面粗糙度带来的不利影响,提高了扩散界面的接触面积,焊合率超过95%;连接界面铜与镍扩散充分且均匀;接头拉伸强度与母材等强,断口位于母材侧,为韧性断口。     

芳基乙炔改性甲基苯基硅树脂的合成及性能

用芳基乙炔改性甲基苯基硅树脂来提高硅树脂及其复合材料的耐热性能.通过红外光谱对其改性前后树脂的结构进行表征;并且测试了复合材料界面剪切强度、弯曲强度和层间剪切强度.测试结果显示,改性后复合材料在室温及200 ℃下的界面剪切强度分别提高了3 MPa和8 MPa;室温下的弯曲强度提高到349.72 MPa,500 ℃烧蚀30 min后复合材料弯曲强度为301.01 MPa;室温下的层间剪切强度为25.21 MPa,经500 ℃烧蚀30 min后降至17.43 MPa,这些性能均高于相应条件下甲基苯基硅树脂复合材料.以上结果表明,芳基乙炔的引入提高了甲基苯基硅树脂的耐热性、界面性能及玻璃纤维复合材料的力学性能.     

15CrMoV钢管的射线检测

阐述了15CrMoV耐热钢管对接焊缝的射线检测技术要点,指出在射线检测工作中,检测人员要严格执行射线检测的有关标准,更要具体地分析该材料的焊接特点,调整检测工艺和方法,避免漏检,更好地保证产品的质量。     

十五升燃料铝贮箱的焊接

介绍了某型号发动机用十五升铝贮箱的焊接方法。针对铝贮箱壳体焊接中容易出现的问题,提出了相应的工艺措施和解决方法,对铝合金的焊接具有一定的参考价值。     

LM-4C Put Yaogan 15 into Space

At 15:31 Beijing time on May 29, a LM-4C launch vehicle lifted off from the Taiyuan Satellite Launch Center and put the Yaogan 15 satellite into its preset orbit. The satellite will mainly be used for scientific experiments, land survey, crops estimation and disaster prevention and reduction, thus will play an active role in China’s national     

TA15钛合金自动TIG焊工艺试验研究

探讨了TA15钛合金自动氩弧焊接工艺,采用恒流TIG焊和脉冲TIG焊,通过无损检测、力学性能试验等手段,分析了工艺参数对接头性能的影响。试验表明,TA15钛合金自动氩弧焊,焊缝外观、内部质量良好,接头抗拉强度达到基体的90%以上,且具有良好的韧性。     

China Plans To Carry Out 15 Launch Missions In 2008

In 2007,China made 10 launch missions and achieved complete success,including the launch of Chang'e-1 satellite,in-orbit delivery of Nigcomsat-1 and 100th launch of Long March series launch vehicle. 2008 will be a peak year in China's space activity history,17     

14th and 15th BeiDou Satellites Launched into Orbit

The 14th and 15th satellites for BeiDou (COMPASS) Navigation Satellite System were launched from the Xichang Satellite Launch Center (XSLC) by a LM-3B GI carrier rocket. While the 16th BeiDou satellite is in space within 2012, a regional network will be     

15CrMoR＋Incoloy825复合板的焊接工艺

通过大量的焊接工艺试验、分析及工艺评定试验验证,确定了15CrMoR＋In—coloy825复合板焊接及在15CrMoR基体上堆焊Incoloy825复合层最佳的焊接工艺规范参数及焊接工艺方法。熔敷金属（包括堆焊金属）的力学性能、化学成分及复合层的耐腐蚀性能等各项技术指标均达到了设计要求。     

Ti-15-3环板的翻孔成型研究

针对Ti—15—3环板零件的形状特点,分析了成型工艺的几种可能性,说明了翻孔成型的优点。详细介绍了钛合金环板翻孔成型工艺过程,对成型中遇到的工艺技术难题提出了解决办法,如工艺参数的选取、成型模具的结构设计及零件回弹量的确定方法等。对此类零件的成型生产具有一定的借鉴作用。     

NEEMO 15: Evaluation of human exploration systems for near-Earth asteroids

The NASA Extreme Environment Mission Operations (NEEMO) 15 mission was focused on evaluating techniques for exploring near-Earth asteroids (NEAs). It began with a University of Delaware autonomous underwater vehicle (AUV) systematically mapping the coral reef for hundreds of meters surrounding the Aquarius habitat. This activity is akin to the type of “far-field survey” approach that may be used by a robotic precursor in advance of a human mission to a NEA. Data from the far-field survey were then examined by the NEEMO science team and follow-up exploration traverses were planned, which used Deepworker single-person submersibles. Science traverses at NEEMO 15 were planned according to a prioritized list of objectives developed by the science team. These objectives were based on review and discussion of previous related marine science research, including previous marine science saturation missions conducted at the Aquarius habitat. AUV data were used to select several areas of scientific interest. The Deepworker science traverses were then executed at these areas of interest during 4 days of the NEEMO 15 mission and provided higher resolution data such as coral species distribution and mortality. These traverses are analogous to the “near-field survey” approach that is expected to be performed by a Multi-Mission Space Exploration Vehicle (MMSEV) during a human mission to a NEA before extravehicular activities (EVAs) are conducted. In addition to the science objectives that were pursued, the NEEMO 15 traverses provided an opportunity to test newly developed software and techniques. Sample collection and instrument deployment on the NEA surface by EVA crew would follow the “near-field survey” in a human NEA mission. Sample collection was not necessary for the purposes of the NEEMO science objectives; however, the engineering and operations objectives during NEEMO 15 were to evaluate different combinations of vehicles, crew members, tools, and equipment that could be used to perform these science objectives on a NEA. Specifically, the productivity and acceptability of simulated NEA exploration activities were systematically quantified and compared when operating with different combinations of crew sizes and exploration systems including MMSEVs, EVA jet packs, and EVA translation devices. Data from NEEMO 15 will be used in conjunction with data from software simulations, parametric analysis, other analog field tests, anchoring models, and integrated testing at Johnson Space Center to inform the evolving architectures and exploration systems being developed by the Human Spaceflight Architecture Team.