Analysis of crack damage mechanism of NiCoCrAlY / AlSiY coating

High-temperature oxidation damage of aero-engine turbine blades has attracted increasing attention. However, oxidation and damage behavior of NiCoCrAlY/AlSiY coatings under thermal cycling remain underexplored. Here we systematically investigate thermal residual-stress evolution and crack-damage mechanisms in NiCoCrAlY/AlSiY coatings subjected to different high-temperature cycles, combining experiments with finite-element simulation. Results clarify crack initiation, propagation paths, and damage modes under cyclic loading. By correlating residual-stress distributions with crack behavior, we elucidate the failure process and governing modes (surface/interfacial, Mode I/II). This work establishes an as-deposited baseline and provides theoretical and experimental guidance for the design, processing, and service application of NiCoCrAlY/AlSiY coatings on high-temperature components.