期刊
ACTA MATERIALIA
卷 132, 期 -, 页码 611-626出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2017.04.042
关键词
Multiscale modelling; Phase field model; Al alloys; theta' precipitates; Dislocation
资金
- European Research Council (ERC) under the European Union's Horizon research and innovation programme (Advanced Grant VIRMETAL) [669141]
- Spanish Ministry of Education [FPU15/00403]
A multiscale approach based on the phase-field model is developed to simulate homogeneous and heterogeneous formation of theta' precipitates during high temperature ageing in Al-Cu alloys. The model parameters that determine the different energy contributions (chemical free energy, interfacial energy, lattice parameters, elastic constants) were obtained from either computational thermodynamics databases or from first-principles density functional theory and molecular statics simulations. From this information, the evolution and equilibrium morphology of the theta' precipitates is simulated in 3D using the phase-field model. The model was able to reproduce the evolution of the different orientation variants of plate-like shaped theta' precipitates with orientation relationship (001)theta'//(001)alpha and [100]theta'//[100]alpha during homogeneous nucleation as well as the heterogeneous nucleation on dislocations, leading to the formation of precipitate arrays. Heterogeneous nucleation on pre-existing dislocation(s) was triggered by the interaction energy between the dislocation stress field and the stress-free transformation strain associated to the nucleation of the theta' precipitates. Moreover, the mechanisms controlling the evolution of the morphology and the equilibrium aspect ratio of the precipitates were ascertained. All the predictions of the multiscale model were in good agreement with experimental data. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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