Effects of TGO with Cavern Defects on TBCs Residual Stress
HAN Zhiyong; ZHANG Hu; DING Kunying
2012 International Conference on Solid State and Materials (ICSSM 2012)
Abstract
CoCrAlY bond coat(BC) and top ceramic coating(TCC) was fabricated on the GH99 super alloy by air plasma spray(APS), interface morphology of both original and after heat treatment were investigated by scanning electron micrograph(SEM), meanwhile TGO cavern defects interface residual stresses were analyzed based upon ABAQUS software using finite element method (FEM). The results show that, fabrication of TBCs and heat treatment can cause rough interface and cavern defects in TGO layer both chemically and physically; cavern defects cause residual stress redistribution in TCC/TGO interface with rather high and low stresses in several TCC/TGO interface area, the more caverns the smaller the stress is; compressive σyy stress in interface of TGO and caverns becomes tensile stress gradually to the middle of the interval of two caverns. Mises stress in the interface of caverns and TGO increase gradually with thermal cycling.
Keywords:Thermal barrier coatings(TBCs); Residual stress; Cavern defects; TGO
|
