Application of a modified Ostwald ripening theory in coarsening of γ′ phases in Ni based single crystal superalloys

A modified Ostwald ripening theory was used to evaluate the coarsening behavior of gamma' phases in Ni based single crystal superalloys during thermal exposure. After introducing a dimensionless factor correlated with volume fraction of gamma' phase into the classical Lifshitz-Slyozov-Wagner (LSW) coarsening theory, this model was thus developed by coupling formulaic interfacial energy and diffusion coefficient (including activation energy and pre-exponential factor) as function of alloy composition. The coarsening rate coefficients and radius sizes of gamma' phases were then presented, which show good agreement with the corresponding experimental results. (C) 2015 Elsevier B.V. All rights reserved.