纳米Ni／CNTs对AP／HTPB推进剂热分解及燃烧性能的影响

采用化学液相沉淀法制备了纳米Ni/CNTs复合催化剂,用SEM、XRD、XPS对纳米Ni/CNTs的形貌、微观结构、组成进行了表征,采用DSC研究了其对AP和AP/HTPB推进剂热分解的催化性能,并考察了纳米Ni/CNTs对AP/HTPB推进剂燃速和压强指数的影响.结果表明,纳米Ni能够均匀包覆在CNTs表面,纳米Ni/CNTs可显著降低AP及AP/HTPB推进剂的热分解峰峰温,使AP及AP/HTPB的总表观分解热明显增大,并能有效提高AP/HTPB推进剂的燃速和降低其压强指数.相同量的纳米Ni/CNTs、纳米Ni和纯CNTs进行对比,纳米Ni/CNTs具有更好的催化性能,表现出较好的正协同催化效应.     

双损耗Al2O3基多孔吸波材料的制备及其吸波性能

基于片状Al₂O₃陶瓷互锁结构强度高的特点,制备出夹杂石墨的高气孔率的Al₂O₃多孔陶瓷,并通过原位还原在多孔骨架中制备出Ni微粒,形成一种轻质的双损耗陶瓷基吸波材料。通过XRD、FE-SEM和EDS研究了还原温度对多孔吸波材料的组成、微观形貌、元素分布和吸波性能的影响。结果表明,还原温度升温至700 ℃可将多孔网络中Ni完全还原,形成以堆叠互锁Al₂O₃为基,夹杂片状石墨和孔表面覆盖Ni微粒的双损耗轻质吸波材料。当复合材料厚度为6.5 mm时,最小反射损耗为-35.01 dB,有效吸收带宽达到1.75 GHz。片状Al₂O₃锁定的石墨片构筑的导电网络,Ni微粒与基体之间的极化效应等共同促进复合材料良好的微波吸收性能。     

NiAl基金属间化合物多晶和单晶合金的力学性能研究

研究了Ｎｉ５０Ａｌ３０Ｆｅ２０金属间化合物合金多晶和单晶室温下拉伸，Ｎｉ５０Ａｌ３０Ｆｅ２０和Ｎｉ５０Ａｌ４０Ｔｉ１０金属间化合物合金多晶和单晶在室温和高温下的压缩性能，以及表面镀镍处理对Ｎｉ５０Ａｌ４０Ｔｉ１０性能的影响。     

航空用不锈钢焊接导管的损伤容限研究

基于断裂力学方法开展了1Cr18Ni9Ti导管TIG焊对接结构的损伤容限分析,在测试其母材和TIG焊接头拉伸性能、断裂韧度和疲劳裂纹扩展速率的基础上,分析其失效模式,确定损伤容限ac。研究结果表明:1Cr18Ni9Ti导管TIG焊对接结构在工况振动载荷下,损伤容限ac为0.9mm,导管失效形式为泄露。     

Invar36合金端面铣削力研究

为了研究Invar36端铣过程中切削参数对切削力的影响规律,进行了切削力的单因素实验。对比分析了Invar36与0Cr18Ni9的切削力,研究了切削过程中切削力信号的产生及特征,并对加工过程中的动态切削力进行了频谱分析。分析了切削速度、每齿进给量和轴向切深对切削力的影响规律,建立了切削参数与切削力之间的数学模型。结果表明:刀具坐标系内的径向分力Fr表征了工件对刀具后刀面的挤压作用,单个切削周期内的切向铣削力Ft的峰值超前径向铣削力Fr的峰值。回归模型中的相关系数表明,切削参数对切削力影响的显著性依次为轴向切深、每齿进给量、切削速度。随着轴向切削力的增大,试件表层的Invar36晶粒扭曲程度更加明显,晶粒扭曲深度也随之加深。     

涂敷目标RCS数值分析与并行计算研究

进行了矩量法在计算涂敷目标雷达散射截面方面的研究.详细推导了将RWG基作为基函数时,任意涂敷目标的电磁流方程表达式.鉴于矩量法计算量过大,耗时太长,使分析与优化遇到实质性的困难,结合RWG基函数特点,在对具体的矩阵方程求解时采用了并行处理.通过计算结果和精确结果对比,证明了此种方法的准确性和有效性,同时并行方法的使用大大降低了计算时间.     

Research on influence of typical microstructure characteristics of Ni base single crystal on creep rupture and deformation analysis of turbo blade

Considering the influence of typical microstructure characteristics on creep performance,a series of UM-F single crystal alloys which had similar element components but different microstructures were used to analyze the relationship between creep life and microstructure characteristics of Ni base single crystal.Three main factors were proposed:misfit,volume fraction of precipitate and maximum matrix channel width.The Microstate parameter Ymicro was established to estimate the deformation state of the materials.The linear relationship between the initial value of microstate parameter Y0 and creep life under a certain temperature/load was affirmed.By analyzing the high temperature region of turbo blade using the material parameters of DD 3,the creep deformation and the life prediction of the critical points of blade were obtained and the result closed to the test.     

汽车用钢板的现状和发展趋势

汽车工业发展推动冶金工业中汽车用钢板的发展,汽车用钢板的发展反过来又促进汽车工业技术进步。针对汽车用钢板的质量要求,本文对汽车用钢板的现状和发展趋势述评了。现代汽车用钢板主要有热轧钢板、冷轧钢板、涂镀层钢板和复合减震钢板。随着汽车减重、防腐、防噪声要求的不断提高,节能和环保是现代化汽车发展的主要趋势,降低油耗、减少废气等已成为汽车工程界主攻的方向。因此汽车用钢板的发展趋势是高强度、深冲压性良好、涂镀层钢板和减震钢板。     

Yield anisotropy and tension/compression asymmetry of a Ni3Al based intermetallic alloy

In order to investigate the yielding behavior of the newly developed Ni 3 Al-based intermetallic alloy IC10, yield stresses have been measured in tension and compression with different orientations. The specimens were cut from a sheet with different angles inclined from the solidification direction. The inclined angles were taken to be 0 , 22.5 , 45 , 67.5 and 90 . All experiments were conducted at room temperature except for orientation 0 , whose deformation temperatures ranged from 298 to 1273 K. Experimental results show that the yield strength of alloy IC10 has the anomalous behavior which has been observed for other Ll 2 -long-range ordered intermetallic alloys, but it is less pronounced. The abnormalities show the following characteristics: (i) the yield strength increases as the temperature is raised below the peak temperature, (ii) yield strength anisotropy, (iii) tension/compression asymmetry. Compared to Ni 3 Al single crystals, the polycrystalline exhibits some different yielding behaviors which may be due to the high volume fraction of c phase.