Numerical Modelling of Diffusion Coupled with Cyclic Oxidation. Application to Alumina-Forming Coatings Used for Industrial Gas Turbine Blades

Abstract

A model using a finite elements code is developed to simulate degradation due to combined cyclic oxidation and interdiffusion in materials used in high temperature components of gas turbines. Coating recession due to cyclic oxidation (oxide growth and spalling) is also modelled using a statistical approach. Interdiffusion between coating and superallloy is modelled to predict total Al depletion in the coating. The phase transformations in the alumina-forming coating and the effects of the precipitates at the coating / superalloy interface are investigated. The results of simulations are compared with experimental data. Effects of diffusion parameters and of cyclic oxidation kinetics are discussed.

Coated single crystal superalloys: processing, characterization, and modeling of protective coatings

“…Basic composition evaluation could be based on binary phase diagram analysis and diffusion coefficient of Ni and Al [165,203,204]. Moreover, this kind of analytical model could be easily linked to oxide loss analysis to consider evolution of realistic boundary condition for diffusion analysis [143].…”