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.