Development and characterization of Zn-xCu-yTi-zMo alloys for biomedical applications: a high-throughput gradient continuous casting approach

The limited mechanical properties of pure Zn, such as its low strength and ductility, hinder its application as a material for biodegradable implants. Addressing this challenge, the current study focuses on the development of biodegradable Zn-based alloys, employing innovative alloy design and processing strategies. Here, alloys with compositions ranging from 0.02 to 0.10 weight percent (wt.%) Cu, 1.22 to 1.80 wt.% Ti, and 0.04 to 0.06 wt.% Mo were produced utilizing a high-throughput gradient continuous casting process. This study highlights three specific alloys: Zn-1.82Cu-0.10Ti-0.05Mo (HR8), Zn-0.08Cu-1.86Ti-0Mo (HR7), and Zn-1.26Cu-0.13Ti-0.06Mo (HR6), which were extensively evaluated for their microstructure, mechanical properties, electrochemical performance, potential as bioimplants, and cytotoxicity. These alloys were found to exhibit enhanced mechanical strength, optimal degradation rates, and superior biocompatibility, evidenced by in-vivo experiments with SD rats, positioning them as promising candidates for medical implants. This research not only introduces a significant advancement in biodegradable alloy development but also proposes an efficient method for their production, marking a pivotal step forward in biomedical engineering. Statement of Significance The limited mechanical properties of pure Zn have hindered its application in biodegradable implants. Our research primarily focuses on the alloy design and process strategies of biodegradable Zn-based alloys. We explore the Zn-Cux-Tix-Mox alloys. This study introduces a high-throughput experimental approach for efficient screening of multi-component alloy systems with optimal properties. The Zn-Cux-Tix-Mox alloys were designed and processed through gradient continuous casting, followed by homogenization and hot rolling. Our findings indicate that the Zn-1.82Cu-0.10Ti-0.05Mo alloy demonstrates superior tensile, mechanical, and corrosion properties post hot rolling. The study suggests that Zn-0.13Cu-1.26Ti-0.06Mo, Zn-0.08Cu-1.86Ti-0Mo, and Zn-1.82Cu-0.10Ti-0.05Mo alloys hold significant potential as biodegradable materials.