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 |
The Columnar/Equiax Solidification Modes in Relation to Segregation in Remelted Nb-Containing Superalloy Ingots |
| Author(s) |
Alec Mitchell, Stephane Hans, Mathieu Garrigue |
| On-Site Speaker (Planned) |
Stephane Hans |
| Abstract Scope |
VAR and ESR ingots of the superalloys generally solidify as a columnar dendritic structure, strongly oriented with the primary growth direction orthogonal to the liquidus surface. However, if the melting is unstable, or the melting rate is high, the structure may transform to equiax crystallisation. The thermal conditions governing this transition are known. Liquid movement during the formation and compaction of the equiax crystal zone may lead to solute concentrations which produce locally dense collections of primary NbC precipitates. If the level of local segregation is sufficiently high as to precipitate also eutectic Laves phase, these areas may locally reduce the LCF properties in the product, leading to the possibility of random variations in the mechanical behaviour. The thermal conditions defining this transition are discussed in relation to remelting practices |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |