SiO2玻璃原位反应合成Al/Al2O3复合材料

利用SiO₂玻璃具有易近成型、致密及各向同性的特点,通过SiO₂玻璃与铝熔体间的反应合成了Al/Al₂O₃复合材料,克服长期以来在合成Al/Al₂O₃复合材料时均采用颗粒反应物的局限。反应产物是一种组织均匀致密的Al 与Al₂O₃互为网络的Al/Al₂O₃陶瓷基复合材料。反应温度升高,整个反应产物中的Al的体积分数上升。Al/Al₂O₃复合组织在三维空间的真实形态中存在着Al相被Al₂O₃完全包围的形态,证明了网络状Al₂O₃组织形成的烧结机理。与合成Al/Al₂O₃的其它工艺相比,本工艺可在1000℃的较低温度进行,并具有反应速度快、断裂韧性和抗弯强度值高的特点。

IN SITU REACTIVE SYNTHESIS OF Al/Al2O3 COMPOSITES USING SILICA GLASS

An innovative technology is presented, by which Al/Al2O3 composites could be synthesized with the reaction between silica glass and aluminum melts, because silica glass has a series of specialities, such as easy to be net-shaped, highly dense, and isotropic. This method could overcome the limitation of granular reactants, which were only used in the course of studying and synthesizing Al/Al2O3 composites up to now. The products are compact, homogeneous and network Al/Al2O3 ceramic matrix composite structures, in which Al and Al2O3 are mutually interpenetrated. The volume fraction of aluminum in Al/Al2O3 would increase with the increase of reactive temperature. Since it is found that there are some aluminum phases encompassed by Al2O3 particles existing in the Al/Al2O3 composites, the microstructure evolution of network Al/Al2O3 is confirmed to be a sintering process. Compared with that of technologies synthesizing Al/Al2O3, the process has the lower reactive temperature of 1000℃, faster reactive rate, and higher values of fracture toughness and bending strength.