简介：Refractorymaterialsaresubjectedtomechanicalandchemicalloadsduringapplication,whichrespectivelyleadtofractureandcorrosion.Theunderstandingofthemechanicalfractureandthemicrostructuralmodificationafterprogressivethermalshocksisnecessaryforthesuitabledesignofhighperformancerefractorymaterials.Thefractureprocesszonecanbedividedintotwoareas,wheredifferenttougheningmechanismsarelikelytotakeplace:thecracktipandthefollowingprocessregioncalledwakeregion.Inthisstudy,theemphasisislaidonthemicrostructuralmechanismsoccurringinthewakeregionofthecrackandthecracktip.Therefore,functionalaggregates,namelyfusedeutecticaggregatesofAl2O3-ZrO2-SiO2andAl2O3-ZrO2,andandalusite,areaddedtoamodelhighaluminacastableformulationbasedontabularalumina.Thediscrepancyinthermalbehaviorbetweenaggregatesandmatrixaswellasphasetransformationsuchasmulliteformationfavorfurtherthenucleationofmicrocracksthatreducethestressfieldatthelevelofthecracktip.Twodifferentgrainfractionsoftabularalumina(0.2-0.6mmor2.24-3.00mm)aresubstitutedbythesefunctionalaggregates.Aftersinteringat1500℃for6h,thesamplesarequenchedupto10timesinairwithoutpressurefrom950℃toroomtemperature.Theresultingelasticpropertiesareexaminedaftereachthermalshockcycle,aswellastheresidualbendingstrengthafter0,1,3,5,7and10thermalshocks.TheseresultsarecorrelatedwithScanningElectronMicroscopyanalysesafterthedifferentthermalshockcycles.