METHOD FOR PROCESSING METAL-REINFORCED CERAMIC COMPOSITES

A new process is developed to form a ceramic containing a three‐dimensional network of metal reinforcement. The process involves four steps: (1) forming a powder compact containing a continuous network of either organic or carbon material by pressure filtration, (2) pyrolyzing the network to form channels within the powder compact, (3) densifying the powder while retaining the channel network, and (4) intruding metal into the channel network by squeeze casting. Pressure filtration is used to form the powder compact containing the pyrolyzable network either by mixing slurries of powder with chopped fiber or by packing powder within pyrolyzable preforms. When pressure is removed after filtration, the differential strain recovery of the powder matrix relative to the organic material can cause damage. Such damage is prevalent for a powder matrix formed from flocced slurries. However, this problem is avoided by using dispersed slurries which produce consolidated bodies that alleviate stresses arising from differential strain recovery by viscous flow. Metal‐reinforced ceramic composites with different reinforcement architectures, volume fractions, and sizes can be produced with this technique. Copyright © 1990, Wiley Blackwell. All rights reserved