Role of interfacial dislocation networks during secondary creep at elevated temperatures in a single crystal Ni-based superalloy

Abstract

Generally, the denser dislocation networks in the γ/γʹ interface should result in a lower minimum creep rate in single crystal Ni-based superalloy at high temperatures. However, in this study, with rising temperature from 1100 °C to 1150 °C, the spacing of dislocation networks decreases almost linearly, while the minimum creep rate increases nonlinearly. This is attributed to the enhanced dislocation-climb in the γ/γʹ interface and γʹ-cutting by a<010> superdislocations. Further, dislocation networks can act as a superdislocation source during the secondary creep stage besides the well-known strengthening effect.