Composition of excess phases in cast heat resistant Ni--Cr alloys

1. Heat tinting revealed the complex and irregular composition of excess phases — blue carbides, yellow-orange nitrides — with distinct boundaries of separation. 2. Microprobe analysis showed that the yellow-orange particles contain Ti and N, while blue particles consist mainly of Nb and C. The presence of other carbide-forming elements (Ti and Mo) in niobium carbide and the small amount of nitrogen and oxygen lead to the assumption that the niobium carbide is of complex composition (oxycarbonitride).