Influence of Ti content on microstructure, mechanical properties and castability of directionally solidified superalloy DZ125L

• With decreasing Ti content of DZ125L, the separation temperature of γ′ decreased.
• Lowering Ti content in DZ125L resulted in free crack casting blades.
• DZ125L alloy needs much lower Ti/Ta ratio to achieve good castability.

Directionally solidified DZ125L alloys of various Ti content were developed by low segregation technology. The microstructure, mechanical properties and castability of directionally solidified superalloy DZ125L were investigated. With decreasing Ti content in DZ125L alloy, the size, volume fraction and separation temperature of γ′ decreased. While the tensile strength and rupture life of directional solidified cylindrical samples is also obviously decreased. Lowering Ti content in alloy resulted in free hot cracking casting blades. Compared with IN792 alloy, DZ125L alloy needs much lower Ti/Ta ratio to achieve good castability.