OPTIMIZATION OF THE MECHANICAL-PROPERTIES OF SILICON CARBIDE-FIBER-REINFORCED ZIRCONIA TITANATE MATRIX COMPOSITES THROUGH CONTROLLED PROCESSING

The effects of processing parameters on the microstructure and mechanical behavior of a SiC-fiber-reinforced ZrTiO4 matrix composite were evaluated through a controlled study. The microstructure was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Mechanical behavior was characterized by strength and toughness measurements, which were correlated with the microstructure of the composite. The optimized processing schedule developed included incorporation of CO-heat-treated BN-coated fibers, composite calcination at 530-degrees-C, and consolidation via hot-pressing at 1270-degrees-C and 17.25 MPa applied pressure in an atmosphere of CO at an overpressure of 111.5 kPa (1.1 atm). Use of this processing schedule improved in situ fiber strength and modified the fiber/matrix interfacial microstructure to ameliorate its sliding and debonding resistance, leading to a composite with average strength over 1 GPa and a toughness of 26 MPa.m1/2.