Crystallization and microstructure formation of glass with Y2Si2O7-mullite eutectic composition

The crystallization and microstructure formation of glass with a Y2Si2O7-mullite eutectic composition were examined. A crystallization of Y2Si2O7 and the mullite phase due to phase separation occurred at 1174 °C, and a well-developed Y2Si2O7 facet crystal was formed. This sample was melted down and solidified via heat treatment at 1250 °C and 1300 °C, temperatures below the melting point of a Y2Si2O7-mullite eutectic. As a result of this solidification, a directional eutectic microstructure was formed.