Repair of nickel-based alloy turbine disk

A method of adding material to a nickel-based superalloy component, such as a gas turbine rotor disk, without damaging the underlying material and without creating an unacceptable level of cracking. The method is advantageously applied in the repair of Alloy 706 turbine rotors having experienced operating failures in the steeple region of the disk. Once the damaged material is removed, replacement nickel-based superalloy material is added using a welding process that protects both the underlying material and the replacement material. The replacement material may be added by welding, with the preheat temperature maintained no lower than 100° C. below the aging temperature of the deposited alloy and with the interpass temperature maintained below the solution annealing temperature of the alloy. Alternatively, the replacement material may be preformed and welded to the original material using a friction welding process. In one embodiment, a replacement steeple of directionally solidified or single crystal material is installed onto a disk hub using a linear friction welding technique.