# Ytterbium-Modified Rapidly Solidified Mg-Zn-Ca Alloys: Improvements in Strength and Corrosion Resistance for Biodegradable Implant Applications

## TL;DR

Adding ytterbium to magnesium-zinc-calcium alloys improves their strength and corrosion resistance, making them better for biodegradable medical implants.

## Contribution

Ytterbium modification is shown to enhance structural and electrochemical properties of Mg-Zn-Ca alloys for biomedical use.

## Key findings

- Adding 2–4 at.% Yb enhances amorphous formation in Mg66Zn30Ca4 alloys.
- Yb addition improves mechanical and electrochemical properties of Mg-Zn-Ca alloys.
- Yb-modified alloys show an oxygen-rich corrosion layer of ~18 μm thickness.

## Abstract

What are the main findings?

Yb addition (2–4 at.%) enhances amorphous formation in Mg66Zn30Ca4 alloys.

Yb addition improved mechanical and electrochemical properties of Mg-Zn-Ca al-loys.

What are the implications of the main findings?

Controlled Yb incorporation optimize structural integrity and biocompatibility in Mg–Zn–Ca–Yb systems.

Yb modification enhances the suitability of Mg-Zn-Ca alloys for biodegradable or-thopedic implants.

Biodegradable alloys are increasingly studied in medical research to find the best balance between mechanical performance and biocompatibility. Magnesium (Mg) alloys are particularly attractive because of their low density, good mechanical properties, and compatibility with the human body. However, rapid corrosion limits their wider use. Recently, Mg alloys containing zinc (Zn) and calcium (Ca) have drawn interest due to more suitable degradation rates. In this study, Mg66Zn30Ca4 was chosen as the base alloy due to its high mechanical strength, excellent biocompatibility, and favorable corrosion behavior, making it an ideal starting point for biodegradable implants. We investigated how adding ytterbium (Yb) affects the mechanical and corrosion behavior of this base alloy. Mg66−xZn30Ca4Ybx (x = 2, 4, 6) rods were produced using rapid solidification, and their mechanical and electrochemical properties were systematically evaluated. The results show that adding Yb significantly improves corrosion resistance while maintaining high mechanical strength, making these materials promising for applications requiring both strength and controlled degradation. Corrosion tests indicated that the surface of the samples developed an oxygen-rich layer approximately 18 μm thick, as identified by EDS mapping. Overall, Yb modification enhances the suitability of Mg-Zn-Ca alloys for biodegradable orthopedic implants.