Abstract
We investigate precipitation dynamics in the presence of a local solute gradient using phase-field simulations. During the homogenization heat treatment of the solidified Inconel 718 alloy, high Nb concentration within the Laves phases or at the core of the secondary arms results in Nb diffusion into the γ matrix. The volume fraction and spatial distribution of precipitation during subsequent annealing can be controlled by tailoring the Nb concentration gradient in the matrix during homogenization. We use a surrogate Ni-Fe-Nb alloy for Inconel 718 to explore the growth dynamics of δ precipitates related to the local Nb concentration levels. The simulations indicate that in the presence of a Nb concentration gradient the growth rate of δ precipitates is higher than in a matrix of uniform average Nb concentration. The higher growth rate is a result of the higher local thermodynamic driving force at the interface between the solute-rich matrix and the δ interface. We propose a phenomenological model to describe the diffusion-controlled growth kinetics of the δ phase under a solute concentration gradient.
| Original language | English |
|---|---|
| Article number | 053401 |
| Journal | Physical Review Materials |
| Volume | 5 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 2021 |
Bibliographical note
Publisher Copyright:©2021 American Physical Society.
Funding
This research was supported by the High-Performance Computing for Manufacturing (HPC4Mfg) program sponsored by the Advanced Manufacturing Office of the U.S. Department of Energy (DOE), and by the Exascale Computing Project (17-SC-20-SC), a collaborative effort of the U.S. DOE Office of Science and the National Nuclear Security Administration. This research used resources of the Oak Ridge Leadership Computing Facility, which is a DOE Office of Science User Facility supported under contract DE-AC05-00OR22725. This work has been partially supported by U.S. DOE. ORNL is managed by UT-Battelle, LLC, under Contract No. DE-AC05-00OR22725 for the U.S. DOE. The U.S. government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for U.S. government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan .
| Funders | Funder number |
|---|---|
| High-Performance Computing for Manufacturing | |
| U.S. Department of Energy | 17-SC-20-SC |
| Office of Science | DE-AC05-00OR22725 |
| National Nuclear Security Administration | |
| Oak Ridge National Laboratory |