Effect of Directional Solidification Condition on Interfacial Reaction between DD6 Single Crystal Superalloy and Zirconia-silica Ceramic Core

摘要

The characterization of the interfaces between DD6 single crystal superalloy and zirconia-silica (ZrO_2-SiO_2) ceramic cores was performed by optical microscope (OM), SEM and EDS analysis in order to study the influence of directional solidification condition on the interfacial reaction. The results showed that there were chemical reactions on interfaces between DD6 melt and ZrO_2-SiO_2 ceramic cores and the main reaction product was Al_2O_3. The interfacial reaction involved a complex, interdependent system including the oxidation of Al element, the destabilization of calcia stabilization zirconia (CSZ) and the formation of liquid phase with low melting point. The intensity of interfacial reaction increased with the increase of pouring temperature and solidification time, but the number and size of reaction zones could not increase together because of the limited Al content in DD6 alloy.