| Abstract Scope |
Superalloys derive their superior high-temperature strength via interactions between ordered γ′ precipitates and matrix dislocations.
However, during creep deformation or cooling from service temperatures, γ/γ′ interfaces (GI) often show irregularities, which can severely deteriorate the high-temperature strength of superalloys.
For example, Parsa et al. (Acta Mater., 2015) reported the
formation of ledges and grooves (LG) over γ′ precipitates after the cooling
of crept samples.
Experiments fail to explain the formation of these irregularities as only the final state can be assessed.
Hence, we present a coupled framework that accounts for the dynamic interaction between dislocations and moving GI and their simultaneous co-evolution.
We employ an appropriate coarse-graining approach to account for the influence of the dislocations on the dynamics of GI and decoupled the glide and climb of dislocation through a time-scale separation scheme.
Using this framework, we show the mechanisms resulting in the formation of LG at the GI. |