低压液相浸渗制造高强度C/A1复合材料

本文提出非润湿性涂层框架浸渗模型,适当设计涂层形态,于低压力下可以实现金属液对涂覆非润湿性涂层纤维的完全浸渗。在1.5MPa浸渗压力下采用Al-Si-Mg合金浸渗涂覆SiC涂层碳纤维实验,结果表明该模型正确可行。所获得的C/Al复合材料试样抗拉强度达900MPa(纤维体积分数V_f=35％)。论文讨论了三种涂层状态下的浸渗结果。     

低压浸渗Preform制备Al_2O_3/Zn合金复合材料

利用液态浸渗技术制备了Al_2O_3/Zn合金复合材料。研究结果表明,在低压下使液态金属浸渗Preform制备金属基复合材料是可行的,浸渗压力低于10MPa;在浸渗过程中,液态金属的温度对浸渗压力有较大影响。所制备的复合材料具有均匀的显微组织,纤维与基体中的活性元素的相互作用有利于Zn合金的共晶组织生核和长大。     

混杂Cf／SiCp／Al复合材料的低压浸渗

提出了混杂低压浸渗模型，理论计算表明：在0.45MPa压力下可实现对非润湿体系浸杂Cf/Al复合材料的完全浸渗。采用超声混杂法制出了SiCp分布均匀的混杂预制型Cf/SiCp，探讨了混杂预制型的均匀性，采用气压浸渗法在1MPa压力下制出了纤维分布均匀的混杂复合材料Cf/SiCp/Al，分析了纤维分布与混杂预制型中SiCp分布的关系。     

颗粒增强金属基复合材料的无压浸渗新工艺

介绍了目前采用的颗粒增强金属基复合材料的制备工艺,重点阐述了碳化硅颗粒增强铝基复合材料的颗粒增强金属基复合材料新工艺,尤其是高体分SiC/Al复合材料的无压浸渗制备新工艺仍属新领域。     

熔体在连续纤维预制型中的浸渗动力学

从理论和实验上研究了熔体沿连续纤维纵向和横向的浸渗动力学。提出了熔体沿连续纤维纵向和横向的漫渗模型，依据达西定律推导出相应的纵向和横向浸渗系数，测定了铝液在碳纤维／碳化硅颗粒混杂预制型中的纵向和横向浸渗速度。结果表明：当熔体浸渗同样距离时，沿垂直于纤维轴向的浸渗速度约是沿平行于纤维轴向浸渗速度的2．0～2．5倍。     

炭／炭复合材料熔融渗Si研究

为了改善航空刹车副用炭／炭复合材料的摩擦磨损性能，对A，B2种试样进行了渗Si处理，在试样A的摩擦磨损试验中，其线性磨损由原来的42μm／次降低到17．56μm/次，摩擦因数较稳定，均为0．36，并且摩擦磨损曲线的线型较好；试样B渗Si后也比渗Si前的摩擦磨损曲线线型好，同时解决了摩擦时的振动问题，但随试样中所生成SiC含量的增加，其摩擦因数由0．40→0．34→0．30降低，静盘线性磨损是由2．0→21．21→69.33μm增加，对应的动盘线性磨损量也由1．4→23．12→52.85μm增加，并从摩擦磨损的机理上进行了分析，实验结果表明，摩擦磨损性能一方面受A，B2种试样的结构性能影响，另一方面是由渗Si后所生成SiC的性能和不同结构决定的。     

真空固体渗钛及其动力学的研究

本文采用铁钛合金、氯化铵、三氧化二铝组成的渗钛剂对45钢、3G_r2W8V钢进行低真空固体渗钛,并研究了渗钛层的组织形貌、相结构、生长过程、硬度和耐磨性.结果表明,用该渗剂可使钢获得硬度高、耐磨性好的渗钛层.渗钛层由TiC构成,硬度为HV_(m,0.05)2800～3800,推荐的渗钛工艺是1000℃×4～6h、这时渗层厚度可达5～7μm.研究发现,钢在快速渗钛后即可形成TiC细晶层,保温时间大于2小时后,TiC晶粒沿〔220〕方向柱状生长.文中在实验的基础上,进一步对渗钛的动力学过程进行了分析,提出可描述该渗钛过程的模型.     

不锈钢纤维增强ZA43复合材料的常压铸渗工艺

通过常压铸渗工艺制备了不锈钢纤维增强ZA43合金复合材料,分析了浸渗时间,N2保护对浸渗过程和复合效果的影响,研究结果表明,在一定时间和体积比下,浸渗过程宏观上是完全的,所获得的复合材料硬度和耐磨性都有不同程度的提高,但纤维与基体界面杂质和反应的控制还需进一步研究。     

无机盐熔渗多孔陶瓷的熔渗动力学分析

阐述了无机盐熔渗多孔陶瓷的熔渗原理，通过对熔渗过程的动力学分析，得出熔渗深度的表达式，分析了影响熔渗过程的主要因素，讨论了可改进熔渗工艺的几个问题，为实验工作的开展提供了有力的理论依据．     

表面活性剂对铜镀覆石墨工艺的影响

铜镀覆石墨工艺是一种新的铜－石墨复合方法，具有简便、易实现等特点。本文对影响该工艺的因素进行了探索，着重讨论了表面活性剂对铜镀覆石墨效果的影响，分析了表面活性剂的类型、浓度及其混合效应对镀覆过程的作用。本文研究认为，可利用混合表面活性剂作为铜镀覆石墨工艺的表面处理剂，并提出了混合表面活性剂的组成。     

高压下石墨到金刚石转变等温线理论计算

本文用统一的排列模型研究石墨及金刚石在高压下的状态方程。假定能量项可以简单相加，冷能形式取为修正的Ｂｉｒｃｈ方程，晶格振动部分用爱因斯坦模型进行计算，电子的热贡献采用低温电子比热和能量形式。利用上述模型我们计算了石墨相变到金刚石以及金刚石溶解的等温线。     

Kinetics of Nitrogen Removal from Molten Steel under Vacuum and Gas-Blowing Conditions

The kinetics of nitrogen removal from molten steel under vacuum and gas-blowing conditions has beenstudied during the VIM process. The experimental results indicated that vacuum affected the kinetics of nitrogenremoval in the range of 67-5 360 Pa. At 67 Pa, the rate of nitrogen removal is controlled by the liquid phase masstransfer of nitrogen in molten steel. At 2 680Pa, the limited step for nitrogen removal from molten steel is the chemical reaction at the metal/gas interface. Under the present experimental conditions, the type (Ar, CO, CO2) and quantity of gas flowed have no evident influences on the rate of nitrogen removal. The ratio of nitrogen removal of gasbubbles is less than 3 %. Based on the experimental results, the mechanism of nitrogen removal during the VDprocess with argon blowing and the other melting or secondary refining processes with carbon-oxygen reaction havebeen discussed. Some new viewpoints are proposed.     

PLC在真空压力浸渍设备控制系统的应用

在分析真空压力浸渍设备的现状和传统浸渍方法的基础上,针对石墨的真空浸渍过程中存在人为因素导致石墨电极生产过程控制不够稳定的问题,提出用PLC实现对真空压力浸渍系统的控制,提高了控制精度,在实践中取得良好的效果.     

硫化铜精矿焙烧的非等温动力学研究

采用DTA，TG结合X-射线衍射分析，对硫化铜精矿的焙烧的动力学进行了研究．发现硫化铜精矿焙烧可以分成两个阶段．在第一个阶段(673～857K)，铜的硫化物被氧化成硫酸盐；在第三个阶段(857～1073K)，生成的硫酸盐将分解为氧化物．其两个阶段都受界面化学反应所控制，表观活化能分别为159．5kJ／mol和242．2H／mol．     

Cathode erosion of graphite and Cu/C materials in airarcs

Cathode erosion of graphite and Cu/C was studied in direct current arcs, which were ignited between two electrodes comprised of two kinds of carbon materials and a tungsten anode in air. The arced zones on the cathode surface were investigated by a scanning electron microscope. Also, the cathode erosion rates of the investigated materials were measured. The results show that two distinct zone can be seen on both cathodes. The eroded area was located at the zone just opposite to the anode and surrounded by a white zone. The arced surface on the Cu/C containing 9.3 % Cu is rougher than that of the pure graphite. Many particles with various sizes distributed on the Cu/C. The vaporization of Cu can lower the surface temperature and reduce the cathode erosion. Therefore, the cathode erosion rate of the Cu/C is lower than that of the pure graphite.     

强磁场下金属熔体中颗粒运动的行为研究

将A1-5Ti-1B中间合金在有无磁场的条件下进行重熔凝固实验,对凝固后的样品金相组织进行了观察．分析了其中未熔化的固相颗粒在组织中的分布和排列状况,结果表明：与不施加磁场时的样品中针状的TiAl3颗粒杂乱无章排列相比,10T强磁场下的样品中呈长轴平行于外场方向排列;同时,重力引起的颗粒沉降行为明显较无磁场时的要弱．说明强磁场对金属熔体中固相颗粒迁移和旋转的行为有重要影响：针状的弱磁性颗粒在形状各向异性的影响下发生了磁致旋转,使之平行于外场排列;而施加强磁场后熔体的表征黏度系数增大抑制了颗粒的沉降行为．因此,可通过改变磁场参数控制凝固组织中强化相的分布和排列,制备性能优良的金属基颗粒复合材料．     

Mechanism of Fume Suppression and Performance on Asphalt of Expanded Graphite for Pavement under High Temperature Condition

Fume suppression mechanisms and the effect of expanded graphite on the performance of asphalt were studied by applying infrared spectroscopy(FT-IR), X-ray diffraction(XRD), scanning electron microscopy(SEM) and comprehensive thermal analysis(TG, DSC). The experimental results confirm that asphalt which is mixed with expandable graphite will expand in the process of hot mix, and the expanded graphite layer will swell by the light component in the asphalt. The light component in the asphalt and PAHs adsorption on expanded graphite surface or part of the plug in the expanded graphite layer between plates made nucleation crystallization growth. And the Van der Waals force and the bonding of the lattice can effectively restrain the asphalt fume release. Meanwhile, the expanding agent with oxidative can spread into the asphalt, leading to asphalt oxygenated and plastic abate, while the ductility decreases. Expanded graphite, SBS modifier and environment- friendly plasticizers are used to composite modified asphalt. According to asphalt fume release experiment, normal test of asphalt performance, Brookfield viscosity test, RTFOT test and asphalt mixture tests(high temperature stability, low temperature stability, water stability), it has been proven that the modified asphalt's performance is better than that of matrix asphalt and equivalent to that of SBS modified asphalt. Furthermore, it has good fume suppression effect.