|About this Abstract
|10th International Symposium on Superalloy 718 and Derivatives (2023)
|Superalloy 718 and Derivatives
|Effects of High-temperature Oxidation on Fatigue Life of Additive-manufactured Alloy 625
|Grace de Leon Nope, Guofeng Wang, Juan Manuel Alvarado Orozco, Brian Gleeson
|On-Site Speaker (Planned)
The effect of thermal oxidation on fatigue performance of additive-manufactured Alloy 625 was studied. Uniaxial fatigue tests at room temperature were performed after exposures at 800°C for 24h, 300h, and 1000h in either air or argon. Exposures in air resulted in chromia-scale formation, internal attack, and subsurface precipitates. Fatigue results indicated a life reduction for the oxidized additive manufactured samples. By contrast, any of the prior high-temperature exposures were not detrimental to the performance of the wrought Alloy 625. Fractographic analysis indicated that crack initiation occurred in the subsurface, closer to the edge, for exposures to oxidation compared to those exposed to argon. The observed behavior in AM-processed samples is attributed to the exacerbation of subsurface defects during oxidation (i.e., internal attack, decohesion in the scale, and subsurface precipitates). These defects act as preferential crack-initiation sites, leading to reduce a reduction in fatigue life.
|Definite: At-meeting proceedings