Thermodynamic study of molten pool during selective laser melting of AlSi10Mg alloy

A study of the thermodynamic behavior during the selective laser melting process of AlSi10Mg alloy was conducted using a combined numerical simulation and experimental approach. A multiphase flow model incorporating gas-liquid-solid phases was established. The numerical simulation results aligned well with experimental findings, affirming the reliability of the numerical model. Insufficient and excessive laser power densitie,s respectively, led to incomplete fusion defects and spherical pore defects. The evolution of the melt pool was primarily influenced by recoil pressure, Marangoni force, and surface tension, resulting in keyhole formation, convective flow, and liquid surface oscillation as characteristic features of melt pool evolution. Solidification process and mechanical analyses revealed that the central region of the melt pool exhibited smaller temperature gradients and higher solidification rates. Properly increasing the scanning speed under suitable laser power conditions is more conducive to optimizing the solidification structure and enhancing the mechanical properties of selective laser melting components. This study elucidates the thermodynamic evolution mechanism during the selective laser melting process of aluminum-based alloys, providing theoretical support and guidance for optimizing the selective laser melting process.