Nanoscale lamellar γ/γ′ structure and preferred distribution of oxide particles in a new ODS superalloy

Two microstructural phenomena have been studied in a newly designed Ni-based ODS superalloy with a high solvus temperature. For the first time, a nanoscale lamellar gamma/gamma' structure was obtained along the elastically soft [100] direction by a eutectoid-like reaction from a severely deformed matrix. In addition, the preferred distribution of semi-coherent Y2Hf2O7 oxide particles was observed only in the gamma phase due to the prior partitioning of Y and O to this phase. The microstructure development during the processing route is discussed based on the solvus temperature of this new ODS superalloy in comparison to commercial ODS superalloys. (C) 2015 Elsevier B.V. All rights reserved.