Creep-fatigue rupture mechanism and microstructure evolution around film-cooling holes in nickel-based DS superalloy specimen. (December 2021)

• Record Type: Journal Article
• Authors: Zhao, Ting; Hu, Xiaoan; Jiang, Yun; Teng, Xuefeng; Liu, Fencheng; Li, Bin; Zhang, Shengliang; Sun, Yantao
• Is Part Of: Intermetallics. Volume 139(2021)
• Publication Date: 2021-12
• Subjects: Nickel-based superalloy -- Creep-fatigue -- Film-cooling hole -- Fracture analyzation -- Damage evolution; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2021.107359
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: In this paper, creep-fatigue behaviors of the thin-walled tubular specimen with film holes were experimentally studied to address the influence of cyclic stress interruptions on creep strength and creep-fatigue life of a directionally solidified superalloy. The specimens with and without multiple holes were designed and manufactured to consider the effect of stress concentration produced by film cooling holes. The creep life of the specimen with holes has reduced significantly with the introduction of fatigue. An interesting result was found that the creep strength and life was enhanced on the stress concentrated specimens even if the creep loading was interruption by fatigue loadings, while creep fatigue life will be commonly shortened for notched specimen. Failure mechanisms related with cooling holes were analyzed on the basis of microscope observation. Highlights: Creep-fatigu tests of specimens with film-cooling holes were carried out. Fatigue creep interaction is reflected in the formation of dimples. High-temperature deformation and stress concentration is a key factor leading to damage. The creep life of the specimen with holes has reduced with the introduction of fatigue. The relationship between rafting type and stress state around film cooling hole was found.