Processing and performance of alumina fiber reinforced alumina composites

Processing alumina fiber-reinforced alumina matrix composites by hot-pressing was described. The mechanical properties of the composites fabricated by different sintering conditions including temperature and pressure have been investigated. The results indicate that the higher sintering temperature and pressure correspond to the higher bulk density and the higher maximum strength of the composite, whereas the pseudo-ductility of the composite is lower. The preliminary results of the composite with monazite-coated fibers show that the maximum strength could be improved up to 35% compared with the non-coated fiber reinforced alumina composite in the same sintering condition. Moreover, the fracture behavior of the composite changes from completely brittle fracture to non-brittle fracture under the suitable sintering conditions. The SEM observation of the fracture surface indicates that the coating works as a protective barrier and avoided the sintering of the fibers together even at high temperature and pressure during the densification process.