Abstract
Phase separation in the γ-γ' alloy 5.2%Al-14.2%Cr-Ni at 873.15 K has been investigated by three-dimensional phase-field simulations, employing a model where both thermodynamic and kinetic parameters were experimentally verified. 510 individual nuclei corresponding to a density of 1024 m-3 were introduced in accordance with classical nucleation theory, and the microstructural evolution was simulated up to a time of 32 h. The microstructural evolution was characterized, and regimes were identified according to the dominant mechanisms for microstructural evolution, where the final regime was found to be a coarsening regime obeying well-known power laws for the particle density and the average γ' particle radius. The evolution of the volume-averaged composition of the particles was found to follow a complicated trajectory, while the composition of individual particles were found to depart significantly from the average. The simulations were compared to experimental results from the literature based on atom probe tomography, and in general good qualitative correspondence was found, albeit with quantitative differences. These are discussed in terms of the assumptions inherent to the phase-field model, and by extension to most common continuum models of diffusive phase transformations.
Original language | English (US) |
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Pages (from-to) | 98-108 |
Number of pages | 11 |
Journal | Acta Materialia |
Volume | 113 |
DOIs | |
State | Published - Jul 1 2016 |
Funding
The authors gratefully acknowledge economic support from DARPA grant W91CRB1010004 , under which part of the work was performed, and SOP additionally gratefully acknowledges economic support from the Carlsberg Foundation grant 2012_01_0787 . The authors thank Dr. Thomas Philippe for providing comments on the manuscript.
Keywords
- Coalescence
- Coarsening
- Ni-Al-Cr
- Phase field modeling
- Phase separation
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Ceramics and Composites
- Polymers and Plastics
- Metals and Alloys