Additive manufacturing of commercially pure magnesium and Mg–2Ag–2Sn alloys by in situ alloying during laser powder bed fusion

Abstract

Despite the advancements in additive manufacturing to prepare personalized implants of complex geometries, the additive manufacturing of Mg alloys has posed significant challenges. In this work, commercially pure (Cp) Mg and Mg–2Ag–2Sn alloys were additively manufactured via laser-powder bed fusion (L-PBF). Elemental powders were ball-milled to prepare the alloy powder for L-PBF. Optimized fabrication parameters were determined by preparing tracks at varying laser parameters. Non-spherical powders could be successfully utilized in this process. Microstructural analysis by optical microscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy revealed the presence of different phases, including some Al uptakes from the substrate. Hardness studies revealed a 63% increase in the hardness of the Mg–2Ag–2Sn alloy compared to Cp Mg. Additionally, the fabricated Mg–2Ag–2Sn alloy system demonstrated almost two-and-a-half-fold improved corrosion resistance than Cp–Mg, making it potentially viable for orthopaedic implants. This study demonstrates the fabrication of Cp Mg via additive manufacturing by laser powder bed fusion (LPBF), accompanied by systematic optimization of the processing parameters. Furthermore, a comparative analysis between pure Mg and the Mg–2Ag–2Sn alloy is conducted to evaluate their properties. The results demonstrate that LPBF is a promising process for the advanced manufacturing of Mg-based alloys for biomedical applications.