Additive manufacturing of magnesium alloys for biomedical applications: Critical review on sinterability and alloy development

Magnesium (Mg) alloys have been receiving increased attention as an emerging class of biomedical metallic materials due to their outstanding combination of biocompatibility and bioresorbability. The customisation of biomedical Mg-based alloys via additive manufacturing (AM) technologies is a revolutionary step towards creating a new generation of Mg implants that are personalised for the patient and designed to resorb as the native tissue heals. AM surpasses the limitations of conventional manufacturing methods by enabling precise control of porosity and microstructure, essential for optimising mechanical strength and degradation rates. However, the inherent properties including low ignition temperature, high vapour pressure, and oxygen affinity make Mg one of the most challenging metals to be processed via AM. Furthermore, poor sinterability limits the efficiency of AM methods. Hence, a comprehensive understanding of the state-of-the-art covering the alloy development efforts on Mg-based systems combining bioresorption rate, sinterability and mechanical performance, and linking with printability and resultant properties of AM-fabricated Mg alloys is what makes this review critical and timely. Ultimately, the objective of this review is to reveal the strong potential of Mg AM for their use as next generation biomedical applications and to highlight challenges that must be addressed to advance their clinical translation. • Critical review of the sinterability of magnesium alloys and the potential solutions towards Mg sinterability enhancement • Summary of the most recent magnesium alloy development studies for biomedical applications combining bio-resorption rates and mechanical performance • Comparison of bio-resorption rates and mechanical properties of additively manufactured magnesium alloys produced by high and low-temperature routes • Overall comparison of magnesium parts produced via conventional routes with additive manufacturing