Evaluation of WEDM performance characteristics of Inconel 706 for turbine disk application

Inconel 706 is a newly developed superalloy, which offers high mechanical strength alongwith easy fabricability thus making it suitable for turbine disk applications. Although Inconel 706 exhibits a substantial increase in stress rupture and tensile yield strength compared to other superalloys, its conventional machining yields poor surface finish and low dimensional accuracy of the machined components. Hence, wire electrical discharge machining (WEDM) of Inconel 706 has been performed and various performance attributes such as material removal rate (MRR), surface roughness (SR), recast surface, topography, microhardness, microstructural and metallurgical changes of the machined components have been evaluated. The experimental results revealed that servo voltage, pulse on time, and pulse off time greatly influence the MRR and SR. Due to high toughness of Inconel 706, no micro cracks were observed on the machined surface. Micro voids and micro globules are significantly reduced at low pulse on time and high servo voltage. But, there is a propensity of thick recast layer formation at high pulse on time and low servo voltage. EDAX analysis of recast surface exposed the existence of Cu and Zn which have migrated from the brass wire. The subsurface microhardness was changed to 80μm due to significant thermal degradation. [Display omitted] •Inconel 706 has been identified as an advanced superalloy as a substitute for Inconel 718 for turbine disk application.•Wire electrical discharge machining (WEDM) of Inconel 706 has been done to explore the usages of WEDM for the manufacturing of gas turbine components.•Various performance characteristics of WEDM process (i.e., material removal rate, surface roughness, recast layer thickness, microhardness, surface topography, microstructural and metallurgical changes) have been evaluated to achieve the feasibility in cutting of complex shaped profiles through Inconel 706.