Additive manufacturing of Mg alloys for biomedical applications: Current status and challenges

Among various biomaterials such as titanium, stainless steel, and cobalt-based alloys, magnesium and magnesium-based alloys are considered as new generation biomaterials due to their ability to completely dissolve in to the body fluids leaving no debris. Comparable mechanical strength to bone, bioabsorbable and bioresorbable property and the ability to control its degradation are the unique characteristics of magnesium-based biomaterials which makes it a natural choice for the development of biomedical implants. Owing to complex shape and design, it is strenuous to mimic hierarchical structures of bones by magnesium-based materials via conventional manufacturing techniques such as casting and other thermo-mechanical processing. Using additive manufacturing (AM), any complex geometry and near net shape of the components can be produced. Manufacturing Mg alloy satisfying compositional, microstructural, and design features as per biomedical design specification through AM process requires thorough understanding of the microstructure-property relationship. In this review, the importance of Mg in biomedical applications, feasibility of manufacturing Mg and its alloys through AM technology, challenges in microstructural engineering to achieve improved mechanical properties and corrosion behaviour are discussed.