Melt Infiltration of SiC/SiC Preforms Using Cr-Si Alloys

The goal of this work was to develop engineered matrix SiC/SiC ceramic composites with crack blunting and self-healing capabilities for 1588 to 1755 K applications. The work optimized the temperature and time conditions for melt-infiltrating SiC/SiC preforms with chromium silicide alloys, and established that these alloys do not react with the coatings on the SiC fibers. Traditional ways of fabricating SiC fiber-based ceramic matrix composites (CMCs) use silicon to melt-infiltrate the CMC preforms, where the Si is often converted to SiC by reaction with carbon. The traditional SiC matrices have poor high-temperature creep properties due to the presence of residual silicon. They also have low fracture toughness and a low matrix cracking stress.