Hybrid additive manufacturing for Zn-Mg casting for biomedical application

Zinc (Zn) and its alloys have been the focus of recent materials and manufacturing research for orthopaedic implants due to their favorable characteristics including desirable mechanical strength, biodegradability, and biocompatibility. In this research, a novel process involving additive manufacturing (AM) augmented casting was employed to fabricate zinc-magnesium (Zn-0.8 Mg) artifacts with surface lattices composed of triply periodic minimal surfaces (TPMS), specifically gyroid. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) analysis confirmed that Zn-Mg intermetallic phases formed at the grain boundary. Micro indentation testing resulted in hardness value ranging from 83.772 to 99.112 HV and an elastic modulus varying from 92.601 to 94.625 GPa. Results from in vitro cell culture experiments showed that cells robustly survived on both TPMS and solid scaffolds, confirming the suitability of the material and structure as biomedical implants. This work suggests that this novel hybrid manufacturing process may be a viable approach to fabricating next generation biodegradable orthopaedic implants.