Strain-Induced Cracking Behavior of Coating/Substrate Systems and Strain Tolerant Design for Thick Coatings

摘要: The life span for a coating attached to its substrate is basic support their desired protective function. Therefore, it necessary find out the causes responsible failure of coatings during service. This paper developed finite element model investigate cracking behavior plasma-sprayed ceramic induced by mismatch strain thermal expansion between and substrate. Crack propagation affected thicknesses was realized virtual crack closure technique (VCCT). residual stresses (σ22 σ12) energy release rate (SERR) at tip pre-crack in are calculated. Results show that σ22 σ12 increases continuously with thickening coatings. SERRs top-coat (TC) were increased thickness coatings, resulting cracks. length coalescence lead spallation, which one main modes plasma sprayed Given that, tolerant design inserting vertical pores It found decreased increase number pores, as well depth. Moreover, appear be crack-resistant, particular thicker suggests helpful extend thick makes fundamental contribution preparation advanced future applications.