2Cr16Ni2MoN不锈钢组织与性能研究

通过拉伸测试、冲击测试、硬度测试、透射电镜及扫描电镜观察分析等手段研究了不同热处理状态下2Cr16Ni2MoN不锈钢的组织与性能.研究结果表明,钢采用低于1000℃的固溶温度,组织中存在未溶的(Cr,Mo)23C6,当固溶温度高于1100℃时,马氏体板条明显粗化,均对钢的力学性能不利,钢比较适宜的固溶温度为1040℃.该钢时效硬化的主要原因是组织中析出与基体共格的(Cr,Fe,Mo)2C碳化物.钢经1040℃固溶,560℃时效可以获得较好的强度与韧性配合.     

SiO2溶胶作用下电沉积锌电极性能研究

 在碱性镀锌液中加入SiO₂溶胶,采用电沉积技术制备电沉积式锌电极,考察镀液中加入SiO₂溶胶对锌电极的电沉积速度、微观形貌及电化学性能的影响规律。研究结果表明：随着镀液中SiO₂溶胶浓度（0～200 mL/L）的增加,锌的电沉积速度逐渐下降;溶胶作用下得到的锌电极的微观表面较平整致密,没有出现较大孔洞,且耐腐蚀性和循环可逆性得到改善;尤其是溶胶浓度为150 mL/L时,锌电极具有最小的腐蚀电流密度,且阴、阳极峰值电位差较小,锌电极的电化学性能最好。     

海洋二号卫星微波散射计自然扩展目标在轨定标

海洋二号卫星微波散射计(HY-2 Scatterometer, HY-2 SCAT)是一种旋转扫描笔形波束散射计, 能够对同一观测面元提供4次方位角和入射角的观测组合, 并通过地球物理模型反演海面风场. 为达到设计的风场反演精度, 要求其系统定标精度达到0.5dB. 利用不同区域自然扩展目标对HY-2 SCAT进行在轨外定标, 并与OSCAT散射计在同时期内的测量结果进行了对比. 定标结果显示可以消除因散射计天线指向偏差带来的方位向测量误差. 针对HY-2 SCAT方位向测量偏差进行了误差分析, 利用仿真方法以及海洋二号卫星雷达高度计同期测量数据的反演结果进行比对, 验证了误差来源.      

由高能电子引发的风云二号C星跳变事件概率分析

通过对地球同步轨道高能电子监测数据(来自GOES)与风云二号卫星跳变事件的对比分析发现, 跳变事件均发生在高能电子增强事件即所谓高能电子暴期间, 因此初步断定, 跳变事件与高能电子引起的卫星介质深层充放电事件有关. 通过对不同通量高能电子增强事件期间所发生的跳变事件发生率进行量化计算, 给出跳变事件发生概率的计算方法, 为卫星在轨运行管理及防护提供参考.      

Generating precise and homogeneous orbits for Jason-1 and Jason-2

Driven by the GMES (Global Monitoring for Environment and Security) and GGOS (Global Geodetic Observing System) initiatives the user community has a strong demand for high-quality altimetry products. In order to derive such high-quality altimetry products, precise orbits for the altimetry satellites are a necessity. With the launch of the TOPEX/Poseidon mission in 1992 a still on-going time series of high-accuracy altimetry measurements of ocean topography started, continued by the altimetry missions Jason-1 in 2001 and Jason-2/OSTM in 2008. This paper contributes to the on-going orbit reprocessing carried out by several groups and presents the efforts of the Navigation Support Office at ESA/ESOC using its NAPEOS software for the generation of precise and homogeneous orbits referring to the same reference frame for the altimetry satellites Jason-1 and Jason-2. Data of all three tracking instruments on-board the satellites (beside the altimeter), i.e. GPS, DORIS, and SLR measurements, were used in a combined data analysis. About 7 years of Jason-1 data and more than 1 year of Jason-2 data were processed. Our processing strategy is close to the GDR-C standards. However, we estimated slightly different scaling factors for the solar radiation pressure model of 0.96 and 0.98 for Jason-1 and Jason-2, respectively. We used 30 s sampled GPS data and introduced 30 s satellite clocks stemming from ESOC’s reprocessing of the combined GPS/GLONASS IGS solution. We present the orbit determination results, focusing on the benefits of adding GPS data to the solution. The fully combined solution was found to give the best orbit results. We reach a post-fit RMS of the GPS phase observation residuals of 6 mm for Jason-1 and 7 mm for Jason-2. The DORIS post-fit residuals clearly benefit from using GPS data in addition, as the DORIS data editing improves. The DORIS observation RMS for the fully combined solution is with 3.5 mm and 3.4 mm, respectively, 0.3 mm better than for the DORIS-SLR solution. Our orbit solution agrees well with external solutions from other analysis centers, as CNES, LCA, and JPL. The orbit differences between our fully combined orbits and the CNES GDR-C orbits are of about 0.8 cm for Jason-1 and at 0.9 cm for Jason-2 in the radial direction. In the cross-track component we observe a clear improvement when adding GPS data to the POD process. The 3D-RMS of the orbit differences reveals a good orbit consistency at 2.7 cm and 2.9 cm for Jason-1 and Jason-2. Our resulting orbit series for both Jason satellites refer to the ITRF2005 reference frame and are provided in sp3 file format on our ftp server.     

电子束物理气相沉积La2Zr2O7热障涂层研究

为克服传统热障涂层材料YSZ耐温性能和隔热性能的不足,以ZrO2和La2O3为原料,采用无压烧结法合成了烧绿石结构化合物La2Zr2O7,用电子束物理气相沉积(EB-PVD)法在高温合金基体上制备了La2Zr2O7涂层,分析了涂层的成分,并对其显微结构、热物理性能与传统YSZ热障涂层进行了对比研究.结果表明,La2Zr2O7涂层成分处于P结构范围内,呈典型的柱状晶结构,柱状晶头部呈明显的金字塔形状.与传统YSZ柱状晶相比,La2Zr2O7涂层的柱状晶紊乱度更大,尺寸更加细小,并且柱状晶上的树枝状亚晶更多.在25～1200℃范围内,La2Zr2O7涂层的热导率最大为0.985W/(m·K),最小为0.796 W/(m·K),大大低于同条件下的YSZ涂层.低本征热导率、小柱状晶直径、大紊乱度、密度轻及高孔隙率是造成La2.Zr2O7涂层低热导率的主要因素.     

Nb＋Ni中间层对Ti2AlNb与GH4169扩散连接接头组织与性能影响

在950～1100℃,20MPa,20～120min的工艺条件下,添加厚度均为10μm的Ni+Nb为中间层,对Ti2AlNb与GH4169真空扩散连接工艺进行了研究.利用扫描电镜(SEM)、能谱分析(EDS)和X射线衍射(XRD)对接头截面和断口的成分和相组成进行了分析.结果表明,添加Ni+Nb做中间层能实现Ti2AlNb与GH4169良好的连接.在GH4169与Ti2AlNb之间生成6层反应层,自GH4169侧依次为:Fe-Ni-Cr固溶体,Ni3Nb,Ni6Nb7,残留Nb层、Ti-Nb固溶体、高铌O相.在剪切试验中,接头沿Ni3Nb层与Nb层之间的Ni6Nb7层断裂.在1050℃,20MPa,40min工艺条件下,剪切强度达到最高,为460MPa.     

纤维表面PIP-SiC涂层对2D-SiC_f/SiC复合材料力学性能影响

采用低浓度先驱体溶液利用先驱体浸渍裂解(PIP)工艺在SiC纤维表面制备了SiC涂层,研究了浸渍裂解次数对纤维涂层形貌的影响.研究表明,采用10%的PCS先驱体溶液经3次浸渍裂解后可在纤维表面制得连续致密的SiC涂层.采用经涂层处理的SiC纤维布经热模压成型-先驱体浸渍裂解工艺制备了2D-SiCf/SiC复合材料,其弯曲强度随制备涂层浸渍裂解次数的增加先增后降,经3次浸渍裂解制备涂层的复合材料强度最高,由未经涂层处理的163.5MPa增大到245.9MPa,强度提高近50%.研究证明,SiC纤维表面SiC涂层使纤维在材料致密化过程所受的损伤减小,同时改善了界面,使复合材料强度明显提高.     

铝合金在模拟SO2污染大气环境中的腐蚀行为

采用扫描电镜(SEM/EDX)、增重法、傅立叶变换红外光谱(FTIR)和X射线衍射研究铝合金1060、铝合金2A12和7A04分别在表面沉积与未沉积70μg/cm2氯化钠条件下在含50×10-6SO2(50ppm)污染大气环境中的腐蚀行为和规律,并测试三种材料力学性能的变化。研究结果表明,随试验时间的延长,铝合金表面腐蚀产物不断增多,腐蚀增重符合指数衰减规律Δm/A=B Dexp(-t/k),抗拉强度和延伸率呈下降趋势;表面腐蚀产物形貌呈团状或圆团状,并不断向外扩展延伸,呈现不均匀的凹凸形貌;铝合金在50ppm SO2污染大气环境中腐蚀产物少,腐蚀增重较少,表面腐蚀产物主要为氧化铝和硫酸铝;而表面沉积70μg/cm2NaC l的铝合金在模拟50ppm SO2污染大气环境中腐蚀产物明显增多,腐蚀增重大,力学性能下降幅度大,二氧化硫和氯化钠的协同作用明显促进铝合金的腐蚀,腐蚀产物主要为氧化铝、铝的硫酸盐和铝的氯化物。