3D-Printed Zn-based Orthopedic Implants: The Effect of Additives on Microstructure, Mechanical Properties and Degradation Behavior (Review)

The rise of additive manufacturing (AM) has fundamentally transformed the production of patient specific biomedical implants, providing unprecedented flexibility in terms of design and customization. Among biodegradable metals, zinc (Zn) has been recognized as a highly promising material due to its optimal corrosion rate and crucial role in bone metabolism. However, its widespread use is limited by its mechanical drawbacks, such as inadequate strength and ductility, which are critical for load–bearing applications. To overcome these limitations, strategic addition of various elements has been extensively explored. Present review provides a comprehensive overview of the current state–of–the–art in 3D-printed Zn–based implants, with a particular focus on the impact of various additives on their properties. We systematically analyze the influence of key elements including magnesium (Mg), copper (Cu), silver (Ag), lithium (Li) and others—on the microstructure, mechanical performance, and degradation behavior of 3D-printed Zn-based implants. The review discusses the influence of these additives on the printing processability and the resultant microstructure and properties of the implants, highlighting the mechanisms behind strength enhancement and corrosion modulation.