碳纤维表面状态对C/C复合材料性能影响的研究

用两种经高温处理的碳纤维织物,以酚醛树脂作为基体先驱体,制备了二维C／C复合材料。通过扫描电镜（SEM）,X－射线光电子能谱（XPS）研究了两种碳纤维（TCF和JCF）的表面状态,测试了C／C复合材料（TCC和JCC）的层间剪切强度,拉伸性能,SEM观察表明,TCF及JCF表面都有沟槽,但TCF横断面呈腰子形非圆形,XPS分析表明TCF表面含氧官能团数量多,力学测试结果为：TCC层间剪切强度（ILSS）高于JCC,达到16．1MPa;TCC拉伸强度,模量均高于JCC,而JCC断裂延伸率达1．1％,是TCC的3倍,拉伸断口SEM分析表明,TCC断口平整,无纤维拔出,呈脆断,JCC断口有纤维拨出,是纤维控制的多层基体断裂。     

干式铣削Al-50wt%Si高硅铝合金刀具磨损与表面粗糙度评价

本文以Al-50wt%Si高硅铝合金为研究对象，采用单因素试验方法进行无涂层硬质合金刀具干式铣削试验，分析切削参数对刀具磨损和表面粗糙度的影响。结果表明：表面粗糙度受每齿进给量的影响最显著，随每齿进给量的增加而增加，当每齿进给量从0.07 mm/z增加到0.16 mm/z时，表面粗糙度增加2倍；刀具磨损受切削速度的影响最显著，随切削速度的增加而增加，当切削速度从140 m/min增加到260 m/min时，切削总长度降低3倍，而刀具后刀面磨损量仅是260 m/min速度下的0.8倍；表面粗糙度随刀具磨损的增加呈现先增加后降低的变化趋势，切削长度从350 mm增加到1 750 mm，刀具磨损量平均增加4.5倍，而表面粗糙度却下降2倍；硬质合金刀具主要的磨损形式为磨粒磨损、崩刃。     

Collaborative manufacturing technologies of structure shape and surface integrity for complex thin-walled components of aero-engine: Status,challenge and tendency

Presently, the service performance of new-generation high-tech equipment is directly affected by the manufacturing quality of complex thin-walled components. A high-efficiency and quality manufacturing of these complex thin-walled components creates a bottleneck that needs to be solved urgently in machinery manufacturing. To address this problem, the collaborative manufacturing of structure shape and surface integrity has emerged as a new process that can shorten processing cycles, improve machining qualities, and reduce costs. This paper summarises the research status on the material removal mechanism, precision control of structure shape, machined surface integrity control and intelligent process control technology of complex thin-walled components. Numerous solutions and technical approaches are then put forward to solve the critical problems in the high-performance manufacturing of complex thin-wall components. The development status, challenge and tendency of collaborative manufacturing technologies in the high-efficiency and quality manufacturing of complex thin-wall components is also discussed.     

GGTm-Ts: A global grid model of weighted mean temperature (Tm) based on surface temperature (Ts) with two modes

With the development of Global Navigation Satellite System (GNSS), the detection of precipitable water vapor (PWV) using the GNSS atmospheric sounding technique becomes a research interest in GNSS meteorology. In the conversion of zenith tropospheric delay (ZTD) to PWV, the weighted mean temperature (Tm) plays a crucial role. Generally, the Tm estimated by the linear regression models based on surface temperature (Ts) cannot meet the requirement for global use, and the accuracy of Tm derived from the empirical models is limited. In this study, a new Tm model, named GGTm-Ts model, was developed using the global geodetic observing system (GGOS) atmosphere Tm data and European Centre for Medium-Range Weather Forecasts (ECMWF) data from 2011 to 2015. Resting upon a global 2.5°*2° grid of coefficients of Tm-Ts linear function, the new model can provide Tm at any site in two modes, one for the case with measured Ts provided, i.e., the accurate mode, the other for the case that Ts provided by a subroutine, i.e., the normal mode. The performance of GGTm-Ts model was assessed against the Bevis formula, GPT2w and GPT2wh model using different data sources in 2016-the GGOS atmosphere and radiosonde data. The results show that the GGTm-Ts model in accurate mode achieves best performance with an improvement of 46.9 %/15.3 %, 37.8 %/19.5 % and 34.4 %/14.2 % over other three models in the GGOS atmosphere/radiosonde comparison. For the normal mode, the GGTm-Ts model outperforms the GPT2w model and achieves equivalence results with the GPT2wh model. Moreover, the impact of Tm on GNSS-PWV was analyzed to validate the performance of the GGTm-Ts model.     

空间级硅橡胶胶黏剂粘结界面改性分析

针对空间级硅橡胶与聚酰亚胺的粘结界面呈现低表面能、粘结可靠性差的现状，利用有机硅烷的润湿和键结作用对界面进行预处理，改善其粘结强度。通过FTIR、¹H-NMR和GC-MS分析，有机硅烷的主要成分中对粘结性能影响较大的是正硅酸丁酯和丙基三甲基硅氧烷，采用两种偶联剂对聚合物表面进行预处理，在聚合物间不同均相结构层通过硅烷相互扩散和互穿网络形成的分子桥可实现致密交联。力学试验表明，经有机硅烷对待粘结界面表面预处理，粘结构件的剪切强度值可达0.65 MPa；选择适当的有机硅烷作为附着力促进剂，利用其有机官能团、成膜性和交联性可提高粘结构件的可靠性。     

Effects of surface topography and specimen thickness on high-speed raindrop impact damage of CFRP laminates

Raindrop impact erosion has been observed since early days of aviation, and can be catastrophic for exposed materials during supersonic flight. A single impact waterjet apparatus is established for mimicking drop impacts at the velocities between 350 m/s and 620 m/s. Carbon Fiber Reinforced Polymer(CFRP) laminates with three different surface morphologies and specimen thicknesses are tested here. A central region with no visible damage has been noticed, surrounded by a “failure ring” with common...     

芳纶纤维表面改性及在EPDM 中的分散性

分别采用超声波法和物理机械法对芳纶纤维进行表面改性,研究了两种处理方法对其表面形貌、

分散性以及EPDM 复合材料性能的影响。结果表明:超声法和机械法使芳纶纤维表面形成差别较大的形貌特

征;其中芳纶经机械处理后呈现良好的分散性,其复合材料的拉伸强度和烧蚀深度分别为11. 3 MPa 和1. 2 mm

(10 phr),优于超声波法处理的结果。