Damage mechanisms during very high cycle fatigue of a coated and grit-blasted Ni-based single-crystal superalloy

TitleDamage mechanisms during very high cycle fatigue of a coated and grit-blasted Ni-based single-crystal superalloy
Publication TypeJournal Article
Year of Publication2021
AuthorsCervellon A, Ormastroni LMaria Bort, Hervier Z, Pollock TM, Pedraza F, Cormier J
JournalInternational Journal of Fatigue
Volume142
ISSN01421123
KeywordsCoating, Oxidation, Recrystallization, Single-crystal superalloy, Very high cycle fatigue
Abstract

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.

DOI10.1016/j.ijfatigue.2020.105962