An investigation into temperature evolution and surface quality of AlSi10Mg components fabricated via selective laser melting technology

Selective Laser Melting (SLM) demonstrates considerable sensitivity to processing parameters in the manufacturing of thin-walled AlSi10Mg components. Nevertheless, the interdependent development of the temperature distribution and residual stresses, as well as their correlation with melt pool stability and the emergence of surface defects, has not been quantitatively elucidated. This gap in understanding impedes the informed selection of optimal process parameters in engineering applications. To address these issues, this study establishes a thermo-structural coupled finite element model for the SLM processing of AlSi10Mg alloy, enabling dynamic monitoring of temperature evolution, melt pool morphology, and stress distribution. The model was rigorously validated against experimental data on melt pool dimensions and residual stresses. The validated framework was employed to systematically analyze the temperature evolution mechanisms of AlSi10Mg during SLM and their dependence on process parameters. Complementary experiments were conducted to assess how these thermal responses influence surface quality. The results reveal that increasing laser power leads to higher peak temperatures, larger melt pools dimensions, and longer molten pool lifetimes. Conversely, higher scanning speed and hatch spacing reduce melt pool size and lifetime. Residual stresses were positively correlated with laser power, scanning speed, and hatch spacing. Furthermore, stress-relief annealing was observed during re-melting process, which becomes more pronounced with higher laser energy density. Within the experimental framework and the SEM-based surface quality assessment criteria employed in this study, the optimal set of process parameters for attaining superior surface quality was identified as follows: a laser power of 340 W, a scanning speed of 1600 mm/s, and a scanning pitch of 140 μm. This parameter combination yields formed tracks that are flat, continuous, and exhibit minimal defects. The findings of this research contribute quantitative insights into the thermo-mechanical coupling mechanisms responsible for defect formation in SLM and provide practical guidance for optimizing the process window and enhancing quality control of the AlSi10Mg alloy.