"Enhanced Laser Powder Bed Fusion of Al2024 Alloy via SiC Nanoparticle Surface Modification and Custom Non-Gaussian Laser Beam Profiles"

The Laser Powder Bed Fusion (LPBF) process has revolutionized metal additive manufacturing; however, certain high-performance aluminium alloys remain difficult to process due to issues such as cracking, porosity, and evaporation of volatile elements. This research presents a combined approach aimed at enabling the LPBF processing of one such alloy, using two complementary strategies. The first strategy focuses on improving the powder feedstock through a surface engineering method, designed to modify the outer properties of the metal particles. This modification enhances the thermal response, flowability, and laser absorption of the powder without altering its core chemistry. A customized fluidized bed system was developed at laboratory and intermediate scales to achieve homogeneous and reproducible surface modification, enabling flexibility for both material characterization and part fabrication studies. The second strategy explores the use of non-standard laser beam profiles to address the limitations of traditional Gaussian beams, which tend to concentrate energy too sharply in the beam centre. By employing alternative energy distributions, the thermal gradients during melting are better controlled, helping to reduce common defects such as keyholing, lack of fusion, and columnar grain formation. These beam profiles also allow for the use of a wider power range, offering adaptability for different alloy systems. Preliminary results show a promising reduction in defect density and improved stability during part fabrication. These findings highlight the importance of both powder tailoring and energy distribution in achieving successful LPBF processing of challenging alloys. This work contributes to broadening the range of aluminium alloys that can be additively manufactured and opens new directions for process design through customized laser profiles and engineered feedstock materials.