| Titre: |
TEM Study of High-Temperature Precipitation of Delta Phase in Inconel 718 Alloy |
| Auteur(s): |
Moukrane Dehmas, Jacques Lacaze, Aliou Niang et Bernard Viguier |
| Journal: |
Advances in Materials Science and Engineering |
| Année: |
2011 |
| Volume: |
2011 |
| Pages: |
9 |
| DOI: |
10.1155/2011/940634 |
| ISSN: |
1687-6822 |
| Résumé: |
Inconel 718 is widely used because of its ability to retain strength at up to 650 degrees C for long periods of time through coherent metastable gamma `' Ni(3)Nb precipitation associated with a smaller volume fraction of gamma' Ni(3)Al precipitates. At very long ageing times at service temperature, gamma `' decomposes to the stable Ni(3)Nb delta phase. This latter phase is also present above the gamma `' solvus and is used for grain control during forging of alloy 718. While most works available on delta precipitation have been performed at temperatures below the gamma `' solvus, it appeared of interest to also investigate the case where delta phase precipitates directly fromthe fccmatrix free of gamma `' precipitates. This was studied by X-ray diffraction and transmission electron microscopy (TEM). TEM observations confirmed the presence of rotation-ordered domains in delta plates, and some unexpected contrast could be explained by double diffraction due to overlapping phases. |
| Projet: |
Département SI2M : Microstructures et Contraintes |
