Processing and mechanical properties of short fibers/Si_3N_(4p) reinforced BaO·Al_2O_3·2SiO_2 ceramic matrix composites

摘要

Dense short silicon carbide (SiC_(sf)) and carbon fibers (C_(sf)) reinforced BaAl_2Si_2O_8 (BAS) glass-ceramic composites with silicon nitride were fabricated by hot-pressing technique. The phase characterization, microstructure, mechanical properties and fracture behavior of the composites were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and three-point bending tests. The results showed that short silicon carbide and carbon fibers disperse homogeneously in BAS matrix, and had good chemical compatibility with the glass-ceramic matrix. The addition of Si_3N_4 could successfully eliminate the microcracks in the BAS matrix induced by the thermal mismatch between the fiber and matrix. Both the added short fibers could effectively reinforce the BAS glass-ceramic by the associated toughening mechanisms such as crack deflection, fiber bridging and pullout effects.