Thermomechanical properties of silicon carbide fiber-reinforced SiAlON-based composites fabricated by reactive melt infiltration

摘要

BN coated SiC (Hi-Nicalon) fiber-reinforeed β'-SiAlON based composites have been fabricated by reactive melt infiltration β'-SiAlON was puoduced in-situ by the reaction of β-Si{sub}3N{sub}4 and AlN reactants in the preforms with Y-Al-Si-O molten glass The wettability of the fibers to the molten glass was improved by infiltration and pyrolysis of perhydropolysilazane. The reaction between the fiber and molten glass was depressed using a controlled N{sub}2 atmosphere. The mechanical properties of the composites at room temperature were significantly influenced by the composition of the nitride reactants introduced into the preforms. The increase of the amount of β'-SiAlON formed in the matrix probably increased the residual tensile radial stress between the fiber and matrix, resulting in the improvement of the mechanical properties. The high temperature mechanical performance could be improved by increasing the packing of nitride reactants into the fabrics before melt infiltration of the glass because of the decrease in the amount of residual glass.