|Title||Damage mechanisms during very high cycle fatigue of a coated and grit-blasted Ni-based single-crystal superalloy|
|Publication Type||Journal Article|
|Year of Publication||2021|
|Authors||Cervellon A, Ormastroni LMaria Bort, Hervier Z, Pollock TM, Pedraza F, Cormier J|
|Journal||International Journal of Fatigue|
|Keywords||Coating, Oxidation, Recrystallization, Single-crystal superalloy, Very high cycle fatigue|
The very high cycle fatigue properties of the Ni-based single-crystal superalloy CMSX-4 coated with an MCrAlY type coating and grit-blasted were studied at 1000 °C, 20 kHz and R = -1. A recrystallized layer thicker than the size of the larger casting pores (>50 μm) drastically reduces the fatigue life without environmental influence. The recrystallized layer and roughness introduced by grit-blasting degrades the environmental resistance of the alloy and the resultant fatigue life. The fatigue life of the coated specimens is also greatly reduced from damage accumulation in the interdiffusion zone by grain boundary cracking, oxidation and internal nitridation.