Short range order heterogeneity on plastic mechanisms in γ-phase nickel-based superalloys

Abstract

The fine structure of slip lines in the γ-phase of Ni-based superalloy single crystals has been investigated by in situ atomic force microscopy observations of the specimen surface during deformation. For the first time, the dislocation structure is discussed in terms of short range order heterogeneity. A stress-driven unlocking mechanism is observed of dislocation pile-ups scanning the short range order in the bulk material. This is strongly enhanced by the propagation of other pile-ups a few hundreds of nanometers apart. A modelling based on elasticity is proposed and discussed.

Acknowledgement

The authors thank L. Cartz for valuable comments and useful suggestions on the manuscript.