Effect of Laser Energy Density During LPBF on the Structure and Mechanical Properties of Al–15Sn–5Pb Alloy

Al-15Sn-5Pb (vol.%) alloy was fabricated by the Laser Powder Bed Fusion (LPBF) method at laser scanning speeds of 0.8, 1.0, and 1.2 m/s and laser powers ranging from 70 to 130 W. The samples were synthesized from a mixture of elemental powders using an ONSINT AM150 3D printer under a flowing argon atmosphere. The structure and mechanical properties under compression tests of the produced material were investigated as a function of the volumetric laser energy density (<i>E</i>) during LPBF. It has been established that low laser energy density during LPBF results in incomplete melting of aluminum particles and a non-uniform distribution of soft inclusions within the material. Increasing the energy density ensures a significantly more uniform distribution of the phases, resulting in the formation of a fine-grained three-phase alloy. It was established that both the ductility and strength of the alloy improve with the increase in <i>E</i> until a critical value is reached. As a result, at <i>E</i> ≥ 48 J·mm^-3, the ultimate strength of the alloy reaches 100 ± 5 MPa, and its deformation before fracture is 15 ± 1%. Substituting one quarter of the tin volume with lead results in a significant increase in the ductility of the LPBF-fabricated aluminum alloy.