Effect of Processing Parameters on the Densification of Magnesium Alloy Fabricated by Laser Powder Bed Fusion

Magnesium (Mg) is a lightweight metal with mechanical properties comparable to cortical bone and excellent biocompatibility. When alloyed with suitable elements and processed using advanced manufacturing techniques, Mg can yield alloys with enhanced performance, making it highly attractive for biomedical implants. Among them, the WE43 alloy, specifically developed for improved properties, has gained increasing attention for biomedical applications. To fully exploit its potential, Laser Powder Bed Fusion (L-PBF) offers the capability to fabricate complex Mg components; however, achieving high density and full interlayer bonding requires careful optimization of process parameters. This study investigates the densification behavior of WE43 fabricated by L-PBF across a range of laser powers (50–200 W) and scan speeds (500–2000 mm/s). Porosity was quantified using two complementary techniques: the Archimedes method and optical microscopy image analysis. At low porosity levels, both methods exhibited consistent trends; however, image analysis method reported slightly lower density values because powder-filled voids were removed during polishing, leaving only continuous pores visible. Increasing volumetric energy density improved relative density by reducing lack of fusion and stabilizing pore morphology. Nevertheless, excessive energy input beyond the optimal window induced melt pool instability and gas entrapment, resulting in keyhole porosity. This study demonstrates the complementary roles of the Archimedes method and optical microscopy image analysis in reliable density quantification of L-PBF processed WE43 alloy. The findings provide valuable process–structure insights to guide parameter optimization and advance the development of Mg-based implants with improved structural integrity.