Microstructure evolution of conventionally cast nickel base superalloy

Abstract

The microstructure evolution of a conventionally cast nickel base superalloy has been investigated during aging treatment at 900°C. It shows that two kinds of γ′ particles existed in the as heat specimens. The finer spherical γ′ ones became notably coarsening. The coarsening kinetics can be approximated by a linear volumetric growth as predicted by LSW theory. The larger cubic γ′ ones sphericised and grew at the expense of finer ones. The primary MC decomposition course was shown in detail, which occurred by the formation of γ′ films, Cr rich M 23 C 6 and Mo rich M 6 C.