| About this Abstract |
| Meeting |
Materials Science & Technology 2020
|
| Symposium
|
High Temperature Corrosion and Degradation of Structural Materials
|
| Presentation Title |
Elucidating Influence of Alloy Composition, Thermal Cycling and Environment on Oxidation Behavior of Engine Exhaust Valve Materials |
| Author(s) |
Rishi Pillai, Marie Romedenne, Allen Haynes, Bruce Pint |
| On-Site Speaker (Planned) |
Rishi Pillai |
| Abstract Scope |
Higher temperatures (T>800 °C) are required in heavy duty engines to increase efficiencies. Oxidation induced chemical failure is a key life limiting mechanism at these temperatures. Consequently, various chromia-forming Ni-base alloys (Rene41, H282, Nim80A, Pyromet31V, IN751), combining excellent oxidation resistance and creep strength are being considered as engine exhaust valve materials.
In the current work, oxidation behavior of model and commercial NiCr alloys was investigated in dry and wet air under thermal cycling conditions between 800-950°C. Coupled thermodynamic-kinetic modeling was performed to understand the role of alloying elements and predict microstructural evolution.
Different growth mechanisms of chromia scales in wet and dry air were observed. Presence of Mn and Si seemed to slightly improve oxidation resistance of the alloys while alloys with higher Ti contents performed poorly, especially at T>850 °C. This research was sponsored by the Department of Energy, Vehicle Technologies Office, Propulsion Materials Program. |