Abstract
We study the epitaxial, columnar growth of (multiply oriented) dendrites/cells for a spot melt in a polycrystalline Al–Cu substrate using two-dimensional, phase-field, direct numerical simulations (DNS) at the full-melt-pool scale. Our main objective is to compare the expensive DNS model to a much cheaper but approximate “line” model in which a single-crystal phase-field simulation is confined to a narrow rectangular geometry. To perform this comparison, we develop algorithms that automatically extract quantities of interest (QoIs) from both DNS and line models. These QoIs allow us to quantitatively assess the assumptions in the line model and help us analyze its discrepancy with the DNS model. We consider four sets of heat source parameters, mimicking welding and additive manufacturing conditions, that create a combination shallow and deep melt pools. Our largest DNS simulation used 16K × 14K grid points in space. Our main findings can be summarized as follows. Under AM conditions, the QoIs of line models are in excellent agreement with the full DNS results for both shallow and deep melt pools. Under welding conditions, the primary spacing of the DNS model is smaller than the prediction of line model. We identify a geometric crowding effect that accounts for the discrepancies between the DNS and line models. We propose two potential mechanisms that determine the response of the microstructure to geometric crowding.
| Original language | English |
|---|---|
| Article number | 111262 |
| Journal | Computational Materials Science |
| Volume | 207 |
| DOIs | |
| State | Published - May 2022 |
Funding
This work was supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Applied Mathematics program under Award Number DE-SC0019393 ; and by the Portugal Foundation for Science and Technology (FCT) and the UT Austin-Portugal program . Any opinions, findings, and conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE. Computing time on the Texas Advanced Computing Centers systems was provided by an allocation from TACC and the NSF. This work was supported by the U.S. Department of Energy, Office of Science, Office of Advanced Scientific Computing Research, Applied Mathematics program under Award Number DE-SC0019393; and by the Portugal Foundation for Science and Technology (FCT) and the UT Austin-Portugal program. Any opinions, findings, and conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the DOE. Computing time on the Texas Advanced Computing Centers systems was provided by an allocation from TACC and the NSF. Notice: This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The US government retains and the publisher, by accepting the article for publication, acknowledges that the US 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 US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ).
| Funders | Funder number |
|---|---|
| Portugal Foundation for Science and Technology | |
| TACC | |
| UT Austin-Portugal | |
| National Science Foundation | |
| U.S. Department of Energy | |
| Office of Science | |
| Advanced Scientific Computing Research | DE-SC0019393 |
| Fundação para a Ciência e a Tecnologia |
Keywords
- Additive manufacturing
- Dendritic growth
- Melt-pool modeling
- Model reduction
- Phase-field method
- Welding
