  The out-of-equilibrium heterogeneous microstructure typical of AlSi10Mg
processed by Laser Powder Bed Fusion (LPBF) is often modified by further heat
treatment to improve its ductility. According to literature, extensive
experimental investigations are generally required in order to optimize these
heat treatments. In the present work, a phase-field approach is developed based
on an extended Kim-Kim-Suzuki (KKS) model to guide and accelerate the
post-treatment optimization. Combined with CALculation of PHAse Diagrams
(CALPHAD) data, this extended KKS model predicts microstructural changes under
anisothermal conditions. To ensure a more physical approach, it takes into
account the enhanced diffusion by quenched-in excess vacancies as well as the
elastic energy due to matrix/precipitate lattice mismatch. As the developed
model includes the computation of the evolution of the thermo-physical
properties, its results are validated through comparison with experimental DSC
curves measured during the non-isothermal loading of as-built LPBF AlSi10Mg.
The computed microstructure evolution reproduces the microstructural
observation and successfully explains the peaks in the DSC heat flow curve. It
thus elucidates the detailed microstructural evolution inside the eutectic
silicon phase by considering the growth and coalescence of silicon precipitates
and the matrix desaturation.
