Laser powder bed fusion of biodegradable magnesium alloys: process, microstructure and properties

Magnesium (Mg) alloys have gained recognition as revolutionary biomaterials, owing to their inherent degradability, favorable biocompatibility and mechanical properties. Additive manufacturing (AM) provides high design flexibility and enables the creation of implants with personalized complex shapes and internal porous structures tailored to individual anatomical and functional needs. Particularly, laser powder bed fusion (LPBF), one prevalent AM technique, utilizes a fine laser beam as heat source and results in tiny molten pool with extremely fast cooling rate, which effectively restricts grain growth, inter-metallic precipitation and macroscopic segregation, thus facilitating the fabrication of high-performance metal parts. This review critically assesses the significance of biodegradable Mg alloys and investigates the feasibility of utilizing LPBF for Mg alloys applications in biomedical field. Detailed discussions on LPBF-processed biomedical Mg alloys parts cover process parameters, microstructure, metallurgical defects, and properties like mechanical performance, corrosion behavior, and biological response in both as-built and post-processed states. Additionally, suggestions for advancing knowledge in LPBF of biodegradable Mg alloys for biomedical applications are highlighted to propel further research and development in this field.