Microstructure evolution of conventionally cast nickel base superalloy

The microstructure evolution of a conventionally cast nickel base superalloy has been investigated during aging treatment at 900 degrees C. It shows that two kinds of gamma ' particles existed in the as heat specimens. The finer spherical gamma ' ones became notably coarsening. The coarsening kinetics can be approximated by a linear volumetric growth as predicted by LSW theory. The larger cubic gamma ' 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 gamma ' films, Cr rich M(23)C(6) and Mo rich M(6)C.