Numerical Simulation and Experimental Investigation of Thermal Behavior, Microstructure Evolution and Mechanical Properties of Cu–10 wt.% Sn Alloy Fabricated by Selective Laser Melting

Selective laser melting (SLM) offers a promising route for fabricating high-performance Cu–Sn alloys; however, the extremely transient thermal behavior of the molten pool and its influence on microstructural evolution and mechanical properties remain insufficiently understood. In this study, a finite element model based on ABAQUS was developed to simulate the transient temperature field and molten pool dynamics of Cu–10Sn alloy during the SLM process. By systematically varying the volumetric energy density (VED), the interplay among molten pool geometry, thermal characteristics, microstructure, and mechanical performance was investigated through a combination of numerical simulation and experimental investigation. The results reveal that increasing VED significantly enlarges the molten pool dimensions, elevates the peak temperature, and intensifies the maximum heating and cooling rates, thereby altering solidification conditions. At a VED of 208.33 J/mm3, the molten pool reached its maximum dimensions, with a length of 230 μm, a width of 161 μm, and a depth of 85 μm, resulting in the highest relative density within the investigated range (98.33%). Under this processing condition, the Cu–10 wt.% Sn (Cu–10Sn) alloy exhibited microhardness values of 190 HV near the solidified areas of melt pool interior and 208.4 HV near the solidified areas of melt pool boundary, accompanied by an ultimate tensile strength of 494 MPa. These findings elucidate the critical role of molten pool thermal behavior in governing microstructural refinement and mechanical properties of SLM-fabricated Cu–10Sn alloys and provide a mechanistic basis for understanding the effect of process parameters.