| About this Abstract |
| Meeting |
Superalloys 2024
|
| Symposium
|
Superalloys 2024
|
| Presentation Title |
E-14: Surface-roughness Effects on Creep Performance In Ni-based Single-crystal Superalloys |
| Author(s) |
Aidan J. O'Donnell, Pawan Chaugule, Jean Briac Le-Graverend |
| On-Site Speaker (Planned) |
Aidan J. O'Donnell |
| Abstract Scope |
Ni-based single-crystal superalloys must endure high temperature applications where creep is the main cause of failure. Coatings to protect against oxidation are not always applicable and oxidation should, therefore, be factored in. Thermogravimetric analyses were performed at 1000°C on René N4 to obtain the oxidation rate depending on the surface roughness. It was observed a strong non-linearity attributed to a transition between chemisorption and physisorption. The evolution of the oxidation rate was then phenomenologically modelled combining Lennard-Jones-type and Gaussian-type equations. The obtained expression was then implemented in a crystal-plasticity model used to predict the lifetime variation depending on the initial value of the surface roughness. The predicted lifetimes were then compared to the creep experiments at 1000°C/200 MPa. The evolution of the lifetime depending on the surface roughness match the evolution of the oxidation rate depending on the roughness and, therefore, the model predictions. Clearly, the results point to the importance of considering the contribution of surface roughness not only for fatigue loading but also to creep, which will allow to better understand creep-fatigue interactions. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |