Numerical simulation of 7/7' microstructural evolutions induced by TCP-phase in the MC2 nickel base single crystal superalloy

摘要

The influence of topologically close packed-phase (TCP-phase) precipitation on the -y/y microstructure evolution of a single crystal superalloy has been studied. Four representative configurations of needle-shaped u,-phase particles observed in the MC2 alloy after creep deformation at 1050°C/160MPa have been selected. Finite element modeling was performed on the selected configurations using a crystal plasticity framework and a viscoplastic approach. The local calculated stress/strain fields in the vicinity of TCP-phase precipitates, especially stress concentration, allow an interpretation of the observed microstructural evolutions (γ-precipitate orientation and thickness). Moreover, our numerical simulation brings a fruitful contribution to the understanding of the phenomenon often observed beyond needle-like (j,-phase: the formation of a distorted γ/γ microstructure in lieu of the expected γ/γ-rafted structure.