Rôle of elastic inhomogeneity in the development of cuboidal microstructures in Ni-based superalloys

Abstract A phase field model accounting for inhomogeneous and anisotropic elasticity has been used to investigate the consequences of inhomogeneous elasticity on the formation and coarsening of cuboidal microstructures in Ni-based superalloys. For that purpose, two- and three-dimensional calculations have been carried out considering high volume fractions of γ ′ precipitates, and accounting for their ordered crystal structure. The analysis of a substantial number of cases with different contrasts of elastic constants highlights the primary role played by the inhomogeneity Δ C ′ of the shear modulus C ′ on the shapes and spatial arrangements of the precipitates. This can be attributed to the sensitivity of the mechanisms involved in coarsening to Δ C ′ . Finally, scanning electron micrographs of the AM1 superalloy are statistically analyzed and discussed in light of the calculations.