Phase-Field Simulation of Solidification Behavior of AlSi10Mg Alloys Manufactured Through Direct Metal Laser Sintering

In this work, we numerically investigate the effect of building direction on the solidification behaviour and microstructure evolution of direct metal laser sintered (DMLS) AlSi10Mg. The building direction, as previously proved in experimental studies, can influence the solidification behavior and promote morphological transitions in cellular dendritic microstructures such as columnar-to-equiaxed transition (CET). We develop a thermal model to systemically address the impact of laser processing conditions and building direction on time-dependent solidification parameters including pulling velocity, thermal gradients, and cooling rates of the molten pool during DMLS of AlSi10Mg alloy. We then study the microstructure evolution of DLMS-AlSi10Mg for horizontal and vertical building directions. The present model includes heterogenous nucleation on inoculant particles that triggers the CET, and its results are consistent with the predictions of a previously developed model. In addition, findings are compared with experimental observations to ensure the accuracy of obtained numerical results.