Microstructure Stability of 4th Generation Single Crystal Superalloy, PWA 1497, during High Temperature Creep Deformation

Abstract

The microstructure stability of 4th generation single crystal superalloy, PWA 1497, during high temperature creep testing is discussed and compared with 2nd generation single crystal PWA 1484 superalloy. Quantitative scanning- and transmission electron microscopy methods are used to characterize the alloy microstructure and its changes during creep deformation at 980°C, especially the formation and subsequent directional coarsening of γ′ precipitates. The results show that the rafting parameter R is a suitable and reliable quantitative measure of the developed rafting.