Investigating the influence of thermal behavior on microstructure during solidification in laser powder bed fusion of AlSi10Mg alloys: A phase-field analysis

The utilization of the laser powder bed fusion (L-PBF) method in additive manufacturing experiments has revealed the intriguing potential to induce morphological evolutions within the solidification microstructure by manipulating the thermal conditions. Transitions of this nature can have a substantial impact on the ultimate texture and material properties of the product. This study utilizes numerical investigations to examine the microstructure evolution of the AlSi10Mg alloy, which is fabricated using the L-PBF process, under different thermal conditions. In order to investigate the changes in the microstructure, we employ a parameter phase-field (PF) model. This model effectively replicates the natural development of nuclei from inoculant particles and accurately simulates the transitions in the morphology. The PF model's validity is determined through the numerical investigation of morphological transitions during directional solidification of the AlSi10Mg alloy. The model's predictions are then compared to the analytical Hunt model. The formation of a columnar microstructure with a significantly reduced secondary dendrite arm spacing is observed when the ratio of the temperature gradient (G) to the solidification rate (R) is increased.