Advanced method for manufacturing hybrid nickel based components by combining single crystal (SX) subcomponents with polycrystalline (PX) structures generated by laser metal deposition (LMD)

Blade Integrated Disks (BLISKs) are turbo engine components consisting of one single part comprising both rotor disk and blades, instead of an assembly of a disk and individual, removable blades. BLISKs typically are machined from a forged solid piece of raw material. For applications such as aviation and power generation these components are exposed to extreme mechanical and thermal loads. Since local loads vary across the part, the joining of single crystal (SX) material and polycrystalline (PX) precipitation hardening alloys provides the opportunity of manufacturing tailored hybrid-BLIKs with adapted properties. Nevertheless, this concept could not be realized up to date because fusing these materials by welding is challenging, such that it is presently classified as non-weldable. In this paper, an alternative approach to metallurgically join single crystal (SX) and polycrystalline (PX) nickel-based components is presented. Initially, a PX interface volume is generated onto an SX blade by Laser Metal Deposition (LMD). In a second step, the turbine blades can be joined with conventional, certified welding processes. The approach is successfully demonstrated with LEK94 as the SX substrate material and Inconel 718 (In718) as the PX additive material.