About this Abstract |
Meeting |
Superalloys 2024
|
Symposium
|
Superalloys 2024
|
Presentation Title |
Formation of the γ'''-Ni2(Cr, Mo, W) phase during a two-step aging heat treatment in HAYNES® 244® Alloy |
Author(s) |
Thomas Mann, Victoria Tucker, Peter Kenesei, Jun-Sang Park, Reza Roumina, Emmanuelle Marquis, Michael Fahrmann, Michael Titus |
On-Site Speaker (Planned) |
Thomas Mann |
Abstract Scope |
Precipitation hardening is the dominant method of achieving high strength in most Ni-based superalloys. The formation of nanoscale precipitates during thermal exposure is often studied to determine the optimal methods of attaining high strength. The commercial Ni-based superalloy, HAYNES® 244® alloy, is strengthened through a novel γ'''-Ni2(Cr,Mo,W) intermetallic phase that forms during a two-step aging cycle. The precipitation kinetics of this intermetallic γ''' phase are sluggish for single-step aging in comparison to the γ' phase in precipitation strengthened Ni-based alloys, but a two-step aging treatment has shown to reliably harden the alloy and improve high temperature properties compared to a single-step aging heat treatment. To investigate the formation and coarsening of this phase, heat treated samples of the 244 alloy were analyzed with high energy in situ and ex situ X-ray techniques such as small angle X-ray scattering and wide angle X-ray scattering as well as Vickers microhardness, electron microscopy, and atom probe tomography. The relationship between hardness, aging parameters, and microstructure evolution are discussed. The enthalpy of formation and precipitate solvus temperature were determined with high temperature differential scanning calorimetry and dilatometry analysis. |
Proceedings Inclusion? |
Definite: At-meeting proceedings |