The effect of morphology of thermally grown oxide on the stress field in a turbine blade with thermal barrier coatings

• A 3D-FEM of a turbine blade with TBCs was developed.
• The effect of TGO morphology on stress distribution was studied.
• The dangerous regions in thermal barrier coatings were predicted.

To study the effect of morphology of thermally grown oxide on the stress distribution and evolution under cyclic thermal loading, a three-dimensional finite element model of a turbine blade with thermal barrier coatings is developed, in which the coating deposition process, high temperature creep and elastic–plastic behavior are taken into account. Based on the simulation results, dangerous regions in thermal barrier coatings can be predicted. It is shown that, during the cooling stage, tensile stress occurs at the peak of thermally grown oxide/bond coating interface, and compressive stress lies in the valley. With the increase of thickness and amplitude of thermally grown oxide, both the maximum tensile and compressive stresses increase, and the stress distribution is more sensitive to its amplitude than thickness.