Precipitation and clustering in the early stages of ageing in Inconel 718

✍ Scribed by Talukder Alam; Mahesh Chaturvedi; Simon P. Ringer; Julie M. Cairney

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 741 KB
• Volume: 527
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/j.msea.2010.08.053

✦ Synopsis

In this report we investigate the onset and evolution of precipitation in the early stages of ageing in the alloy WE 91, a variant of the Ni-Fe-Cr superalloy Inconel 718 (IN718). Transmission electron microscopy and atom probe tomography were used to study the size and volume fraction of ␥ and ␥ precipitates and the extent of pre-precipitate clustering of Al/Ti and Nb.

Co-located ␥ and ␥ precipitates were observed from the shortest ageing times that precipitates could be visualised using atom probe. At shorter times, prior to the observation of precipitates, clustering of Al/Ti and Nb was shown to occur. The respective volume fraction of the ␥ and ␥ precipitates and the clustering of Al/Ti and Nb suggest that ␥ nucleates prior to ␥ during ageing at 706 • C for this alloy.