Measurements of Stress Distribution in top Coat and TGO Layers Processed by EB–PVD

Abstract

Measurements of stress distributions in top coat and TGO layers of EB–PVD TBC have been carried out. It is found that the stress in the top coat layer in as deposited state is –3.5 GPa and it reduces to ∼1 GPa after isothermal heat exposure in air. The stress in the TGO layer is an order of –1 GPa. The stress in the top coat layer decreases with the increase of heat exposure time and that in the TGO layer vice versa. This change originates from the release of residual stress during deposition process and change in force-balance, which originates from the growth of TGO layer.