Given the inherent complexity and specific mechanical properties of the natural bone structures, Additive Manufacturing (AM) emerges as a promising method for bone replacement, attributed to its superior design flexibility and ability to tailor mechanical properties. To date, such implants are limited to non-degradable metals, which pose challenges for maturing adolescent bones, necessitating revision surgeries. In contrast, biodegradable materials, which promote bone growth while degrading, present a viable alternative. Zinc (Zn), a biocompatible and biodegradable metal, holds a high potential for bone replacement due to its optimal degradation rate compared to iron and magnesium. However, its low mechanical strength is a drawback, which can be enhanced by alloying with non-toxic, biocompatible elements like Mg to improve strength while maintaining biodegradability.

Thermodynamic calculations identified Zn-1Mg (wt. %) as a promising alloy for this study. Optimisation of process parameters for the laser powder bed fusion (L-PBF) was carried out with a focus on laser power, scanning speed and hatch distance using an AconityMIDI printer. Densities of as-printed samples were primarily assessed through image analysis of light optical microscope images. The presence of phases was identified using X-ray diffraction while scanning electron microscopy was utilised for microstructural characterisation. Energy-dispersive X-ray spectroscopy was also carried out to produce elemental composition maps, facilitating the preliminary analysis of element segregation and formation of phases. To analyse mechanical properties, microhardness was measured as an initial quantification, complemented by tensile testing.

An optimised processing window was determined for Zn-1Mg with densities >99.5 %. Microstructural analysis and X-ray diffraction confirmed a dendritic microstructure with grain size reduction and homogeneous distribution of fine Mg₂Zn₁₁ precipitates as primary strengthening mechanisms for Zn-1Mg. Microhardness measurements and tensile testing demonstrated superior mechanical strength for Zn-1Mg compared to pure Zn. Future work aims to evaluate degradative properties. In conclusion, this ongoing systematic study of additively manufactured Zn-1Mg indicates its prospective utility for bone replacement, suggesting the need for continued investigation.