| Abstract Scope |
Single crystal Ni-base superalloys (SXs) rely for their high temperature strength on the well known γ/γ’-microstructure. Since more than 60 years, processing routes for SXs have been established and microstructural evolution has been successfully studied (dendritic solidification, multiple step heat treatments, filling of γ-channels with dislocations, formation of networks, rafting, pairwise cutting of the γ’-phase, …). Research on elementary processes in the high temperature low stress creep regime (T>1000°C, σ<300 MPa) has started around the year 2000. Results from the last two decades are presented. These include the pairwise cutting of the γ’-phase by dislocations of different Burgers vectors and the formation of ledges and grooves at γ/γ’-interfaces. The role of misfit in mediating coupled knitting-in/knitting-out reactions of dislocations with dislocation networks and the role of topological inversion in tertiary creep are discussed. |