About this Abstract |
Meeting |
Superalloys 2021
|
Symposium
|
Superalloys 2021
|
Presentation Title |
Creep, Fatigue, and Oxidation Interactions during High and Very High Cycle Fatigue at Elevated Temperature of Nickel-base Single Crystal Superalloys |
Author(s) |
Alice Cervellon, Jianzhang Z. Yi, Fabien Corpace, Zéline Hervier, Joe Rigney, P. K. Wright, Chris J. Torbet, Jonathan Cormier, J. Wayne Jones, Tresa M. Pollock |
On-Site Speaker (Planned) |
Alice Cervellon |
Abstract Scope |
High-temperature fatigue of Ni-based single crystal superalloys is studied at 1000 °C in a wide range of loading conditions (-1 ≤ R ≤ 0.8) and number of cycles (103 – 109). Under fully reversed conditions, a competition between crack initiation from the surface – assisted by oxidation – and from internal metallurgical defects – mostly large casting pores – is observed. Increasing the testing frequency shifts the competition to a higher number of cycles. Conversely, decreasing the casting pore size or coating the specimen promotes surface initiations. When a positive mean stress is added (R ≥ 0), a creep deformation/damage mechanism mainly controls fatigue life, despite fracture surfaces presenting a variety of initiation types. Fatigue life can be predicted by a simple creep law if the contribution of the alternating stress is considered. A linear damage summation method that considers pure fatigue and pure creep damage is used to predict the fatigue lives and Haigh diagrams for different alloys are presented. |
Proceedings Inclusion? |
Undecided |