Matching time and spatial scales of rapid solidification: Dynamic TEM experiments coupled to CALPHAD-informed phase-field simulations
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
A combination of dynamic transmission electron microscopy (DTEM) experiments and CALPHAD-informed phase-field simulations was used to study rapid solidification in Cu–Ni thin-film alloys. Experiments — conducted in the DTEM — consisted of in situ laser melting and determination of the solidification kinetics by monitoring the solid–liquid interface and the overall microstructure evolution (time-resolved measurements) during the solidification process. Modelling of the Cu–Ni alloy microstructure evolution was based on a phase-field model that included realistic Gibbs energies and diffusion coefficients from the CALPHAD framework (thermodynamic and mobility databases). DTEM and post mortem experiments highlighted the formation of microsegregation-free columnar grains with interface velocities varying from ~0.1 to ~0.6 m s-1. After an ‘incubation’ time, the velocity of the planar solid–liquid interface accelerated until solidification was complete. In addition, a decrease of the temperature gradient induced a decrease in the interface velocity. The modelling strategy permitted the simulation (in 1D and 2D) of the solidification process from the initially diffusion-controlled to the nearly partitionless regimes. Finally, results of DTEM experiments and phase-field simulations(grain morphology, solute distribution, and solid–liquid interface velocity) were consistent at similar time (μs) and spatial scales (μm).
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States); Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344; AC05-00OR22725
- OSTI ID:
- 1415558
- Alternate ID(s):
- OSTI ID: 1474574
- Report Number(s):
- LLNL-JRNL-727840; TRN: US1800836
- Journal Information:
- Modelling and Simulation in Materials Science and Engineering, Vol. 26, Issue 1; ISSN 0965-0393
- Publisher:
- IOP PublishingCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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