CALPHAD-informed phase-field modeling of grain boundary microchemistry and precipitation in Al-Zn-Mg-Cu alloys
نویسندگان
چکیده
The grain boundary (GB) microchemistry and precipitation behaviour in high-strength Al-Zn-Mg-Cu alloys has an important influence on their mechanical electrochemical properties. Simulation of the GB segregation, precipitation, solute distribution these requires accurate description thermodynamics kinetics this multi-component system. CALPHAD databases have been successfully developed for equilibrium thermodynamic calculations complex systems, recent years combined with diffusion simulations. In work, we directly incorporated a database into phase-field framework, to simulate, high fidelity, non-equilibrium microstructures that develop commercial during heat treatment. particular, diffusion, precipitate number density, far-field matrix composition, growth population ?-precipitates, was systematically investigated model alloy near AA7050 composition. It is shown early stages ageing highly heterogeneous strongly affected by ?-precipitates. Significant Mg Cu segregation predicted remain overageing, while Zn rapidly depleted. This non-trivial markedly influenced resulting morphologies, but overall transformation were relatively unaffected. Furthermore, depletion adjacent largely determined which will affect development free zones ageing. simulation results compared scanning transmission electron microscopy atom probe tomography characterisation similar good agreement.
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ژورنال
عنوان ژورنال: Acta Materialia
سال: 2021
ISSN: ['1873-2453', '1359-6454']
DOI: https://doi.org/10.1016/j.actamat.2021.116966