Extreme environments lead to failure of hot section components of gas turbines. To include high-temperature corrosion mechanisms in lifetime estimation models for industrial applications is still an open challenge. In this work we develop a multiphysical model that couples a phase-field fracture model with a multiphase-multicomponent high-temperature oxidation model. It allows us to consider the interactions between diffusion of superalloy components, oxide layer formation, strain and stress as well as crack initiation and growth. This model as well as future extensions will be validated by mechanical, creep and ultra-high cycle fatigue experiments where specimens experience a combination of mechanical, thermal and corrosive loads. With the application to a combustion chamber of a micro gas turbine under realistic conditions we will contribute an advancement of lifetime estimation.