About this Abstract |
| Meeting |
11th International Symposium on Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
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| Symposium
|
Superalloy 718 and Derivatives 2026: Legacy, Innovations, and Future Directions
|
| Presentation Title |
Mechanical Behaviour and Microstructure Changes During Heat Treatment of Nickel-Based Superalloy AD730® |
| Author(s) |
Emeline Nomede-Martyr, Florence Hamon, Laurane Finet, Christian Dumont, Patrick Villechaise, Jonathan Cormier |
| On-Site Speaker (Planned) |
Emeline Nomede-Martyr |
| Abstract Scope |
Turbine discs are designed to have excellent mechanical properties at high temperatures for engine operation. However, some process operations, such as solution heat treatment (SHT) quenching, lead to the introduction of high residual stress magnitudes. These stress levels can lead to part distortion or even cracking during subsequent machining operations. The quench rate controls both residual stresses and precipitate evolution, with opposing effects: higher quench rates increase residual stress magnitudes while refining precipitates size, enhancing mechanical strength. The problem is to understand how residual stresses generated during SHT quenching can be released without affecting too much final mechanical properties of the material. One method to reduce these residual stresses is to tailor a specific ageing heat-treatment. To understand the residual stresses/mechanical properties evolution during heat-treatment in AD730 γ/γ’ superalloy, sub-solvus heat treatment using a monocrystalline structure were used. Samples were treated with different quenching rates and ageing heat treatments. As a result, different microstructures were obtained, which were observed by SEM, allowing us to discuss the relationships between microstructures, heat-treatments and mechanical properties. Then, tensile, creep and relaxation tests were performed to compare the performances of various heat-treatments. The monocrystalline structure enabled us to study a grain boundary-free structure and assess if the conditions employed are sufficient to achieve a favourable relaxation kinetic, which is typically slower in monocrystalline materials. Subsequently, the polycrystalline microstructure will be utilised to deepen our understanding of the effects of ageing. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |