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以Mg为助渗剂,采用液态铝自发熔渗经氧化处理的SiC粉体压坯的方法,制备出高增强体含量的SiCp/Al复合材料。通过考察铝液在SiC粉体压坯中的渗入高度与温度、时间的关系来研究铝液的熔渗机理,并对SiCp/Al复合材料进行X射线衍射、能量散射谱和金相分析。结果表明:在熔渗前沿发生的液-固界面化学反应促进两相润湿,毛细管力导致铝液自发渗入到SiC多孔陶瓷中;熔渗高度与时间呈抛物线关系。熔渗激活能为166kJ/mol,这表明渗透过程受界面反应控制。经氧化处理的SiC粉体均匀地分布在金属基体中,其轮廓清晰。在SiCp/Al复合材料中未发现Al4C3的存在。
Using Mg as penetration enhancer, the SiCp / Al composites with high reinforcement content were prepared by spontaneous infiltration of oxidized SiC powder compact by liquid aluminum. The infiltration mechanism of molten aluminum was investigated by examining the infiltration height of molten aluminum in the SiC powder compact and its relationship with temperature and time. The X-ray diffraction, energy dispersive spectrum and metallographic analysis of SiCp / Al composites were carried out. The results show that the liquid-solid interfacial chemical reaction at the melt infiltration front promotes two-phase wetting, and the capillary force causes the liquid aluminum to spontaneously infiltrate into the porous SiC ceramics. The infiltration height is parabolic with time. Infiltration activation energy is 166 kJ / mol, indicating that the infiltration process is controlled by the interfacial reaction. The oxidized SiC powder is uniformly distributed in the metal matrix with a clear outline. No Al4C3 was found in the SiCp / Al composites.