In Situ Investigations on Stress and Microstructure Evolution in Polycrystalline Ti(C,N)/α-Al2O3 CVD Coatings under Thermal Cycling Loads

The stress behavior and the associated microstructure evolution of industrial Ti(C,N)/α-Al2O3 coatings subjected to thermal cycling are investigated by in situ energy dispersive synchrotron X-ray diffraction transmission electron microscopy. Temperature-dependent stresses changes microstructural parameters (domain size microstrain) analyzed measurements at different temperatures between 25 800 °C, both heating up cooling down step, including several cycles. Transmission microscopy is used evaluate defects before after treatment. introduction high compressive α-Al2O3 top-blasting connected a defect density basal planes alumina layer. relaxation layer with successive annihilation until reversible temperature-dependent condition set. Top-blasting does not change initial residual Ti(C,N) shows cyclic heat treatment an elastic deformation temperature range investigated.