Modeling of Residual Stress in Oxide Scales

摘要: The magnitude of the residual stress in an oxidescale, and how this varies with temperature, is majorimportance understanding failure mechanisms ofoxide scales. This encompasses both growth stresses introduced at oxidationtemperature thermal-expansion-mismatch stressesinduced on heating cooling, as well anyexternally applied or relaxation whichtakes place scale/substrate system. Althoughsome these components are reasonably understood(e.g., thermal stresses), therelaxation total scale by creep orfracture processes much less understood. Inthis study a model has been developed to predict stressgeneration oxide scales functionof time temperature for isothermal exposure cooling room temperature. modeldetermines thermal-stress generationin balanced thesubstrate. substrate then allowed relax stressesrecalculated. accurately predicts theroom-temperature range ofscale/alloy systems. can be used show howthe depends oxidation temperature,cooling rate, substrate, thickness. modelpredictions discussed light experimentalobservations alumina FeCrAlY.