Process for increasing the room-temperature ductility of a workpiece composed of an oxide-dispersion-hardened nickel based superalloy and existing as coarse, longitudinally oriented columnar crystallites

摘要

Process for increasing the room-temperature ductility of a workpiece composed of oxide-dispersion-hardened nickel-base superalloy and existing as coarse, longitudinally oriented columnar crystallites by subjecting the previously zone-annealed workpiece to a solution anneal in the temperature range between 1,160° and 1,280° C. under argon atmosphere for 1/2 h to 5 h and then to a purposefully chosen cooling down at a rate of 0.1° C./min to 5° C./min to a temperature of 500° to 700° C. Thereafter the workpiece is cooled down to room temperature in air. Preferred purposefully chosen cooling down rate: approx. 0.5° C./min.