About this Abstract |
Meeting |
5th International Congress on 3D Materials Science (3DMS 2021)
|
Symposium
|
5th International Congress on 3D Materials Science (3DMS 2021)
|
Presentation Title |
Precipitation and Strengthening in AlCoCrFeNi High Entropy Alloys as Studied by Atom Probe Tomography |
Author(s) |
Keith E. Knipling, Patrick Callahan, David Beaudry |
On-Site Speaker (Planned) |
Keith E. Knipling |
Abstract Scope |
High entropy alloys (HEAs) typically contain five or more principal elements in nearly equiatomic proportions, significantly expanding the composition space and achievable properties of novel metallic materials. In this study we present the complex three-dimensional nanoscale microstructures formed in Al<sub>0.5</sub>CoCrFeNi (atomic fraction) HEAs in the as-cast state and after thermal aging at 700 and 1000 °C. The alloy solidifies into dendritic regions that have a face-centered cubic (FCC) crystal structure enriched in Co, Cr, and Fe, and interdendritic regions that are comprised of a disordered body-centered cubic (BCC, A2) phase and an ordered BCC phase (B2) formed by spinodal decomposition. During aging these regions form a variety of strengthening precipitates, including NiAl (B2 structure), Ni<sub>3</sub>Al (L1<sub>2</sub>), and α-Cr (BCC). Atomic-scale clustering and ordering is assessed in three dimensions using atom-probe tomography and these experimental results are compared with the equilibrium phases predicted by thermodynamic modeling. |
Proceedings Inclusion? |
Definite: Other |