Performance Enhancement in RMI-Fabricated SiC-Ti3SiC2 Composites via Microstructure Optimization

This study focused on improving SiC-Ti3SiC2 composites fabricated through reactive melt infiltration (RMI) using TiSi2 alloy to optimize their microstructure, mechanical, and corrosion properties. The results indicated that achieving a balance between the carbon black content and the porosity of the preforms led to a decrease in residual TiSi2 and an increase in the content of the MAX phase in the composites. The composite, derived from a SiC60-C40 preform with 35% porosity, contained 76 vol.% SiC, 22 vol.% Ti3SiC2, and 2 vol.% TiSi2. The “time window” based on two reactions specific to the TiSi2 and C facilitates the creation of infiltration channels and the reduction of residual TiSi2. With minimal residual TiSi2, the composite exhibited a flexural strength of 395 MPa, a fracture toughness of 5.24 MPa·m1/2, and maintained over 70% of its original strength after thermal shock below 1200ºC. Enhanced corrosion resistance was attributed to a protective MgTiO3 layer.