Investigation on the preparation, microstructure, mechanical and degradation properties of laser additive manufactured Zn–Li–Mg alloy for bioresorbable application

Abstract

Zinc (Zn) is a potential bioresorbable metal material (BMM) with a degradation rate lower than magnesium and higher than iron. However, clinical applications of pure Zn are limited due to its poor mechanical properties and localized degrading tendency. Overcoming these drawbacks is made possible by the process of alloying. The Zn-0.6Li-0.5Mg alloy samples were prepared using the laser powder bed fusion (LPBF) process in this work. The innovative technique combining fast solidification produced by LPBF and alloying with Li and Mg was presented to enhance the mechanical properties of Zn in this work. The relative density, microstructure, mechanical properties, and corrosion resistance of LPBF-built Zn-0.6Li-0.5Mg alloy were investigated. According to the results, the LPBF fabricated Zn-0.6Li-0.5Mg alloy with fine equiaxed α-Zn grains were uniformly distributed with precipitated Mg2Zn11 and LiZn4 at grain boundaries. More interestingly, the average grain size of α-Zn was recorded at 7.2 ± 3.2 μm with Li and Mg. Due to the rapid solidification process, Mg dissolved primarily in the Zn matrix and developed a supersaturated solid solution. As a result, with the addition of Li and Mg, the mechanical properties of the Zn matrix increased considerably. When combined, Zn-0.6Li-0.5Mg alloy can be an attractive candidate for bioresorbable medical implants in orthopedic applications.

Keywords

• Additive manufacturing
• Zn–Li–Mg alloys
• Mechanical properties
• Laser powder bed fusion