Degradable Zn–5Ce alloys with high strength, suitable degradability, good cytocompatibility, and osteogenic differentiation fabricated via hot-rolling, hot-extrusion, and high-pressure torsion for potential load-bearing bone-implant application

• Published in: Journal of materials research and technology Vol. 28; pp. 1752 - 1763
• Main Authors: Tong, Xian, Hong, Xinhua, Chen, Liang, Zhang, Yaru, Wang, Yilin, Chen, Yuge, Zhu, Yunpeng, Wang, Cheng, Zhu, Li, Lin, Jixing, Huang, Shengbin, Ma, Jianfeng, Luo, Peng
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024; Elsevier
• Subjects: Bio-tribological behavior; Biocompatibility; Corrosion behavior; High-pressure torsion; Zn-RE alloy; Biocompatibility; Bio-tribological behavior; Corrosion behavior; Zn-RE alloy; High-pressure torsion
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2023.12.098

Zinc (Zn)-based alloys are considered the next-generation biodegradable material for promising bone-implant devices due to their good degradability, formability, and functionality. Nevertheless, the as-cast Zn alloys showed a low strength-toughness, making it challenging to meet the mechanical properties requirements for high-load-bearing bone implants due to their hexagonal close-packed structure, coarse grain size, and less sliding system. Herein, we have developed biodegradable Zn–5Ce alloys by cerium (Ce) alloying followed by hot-rolling, hot-extrusion, and high-pressure torsion (HPT), respectively, for potential bone-implant application. Mechanical testing revealed that the HPT sample exhibited the best mechanical performance matching among the Zn–5Ce samples with a high ultimate tensile strength of ∼345 MPa, yield strength of ∼230 MPa, a moderate elongation of ∼11.4%, and macro-hardness of ∼96.6 HB. Electrochemical corrosion and static immersion testing revealed that the HPT sample showed the highest electrochemical corrosion rate of ∼416 μm/y and degradation rate of ∼43.8 μm/y in Hanks' solution among the Zn–5Ce samples, which is suitable for degradation rate requirements for bone-implant application. Bio-tribological testing revealed that the HPT sample showed high bio-tribological properties matching in Hanks’ solution with the lowest friction coefficients of ∼0.530 and moderate wear loss of ∼2.2 mg. Cytocompatibility and osteogenic differentiation assessment revealed that the diluted extract of the HPT sample showed the highest cytocompatibility towards 3T3 and MG-63 cells and osteogenic differentiation performance towards 3T3 cells among the most diluted extracts. Accordingly, the HPT Zn–5Ce sample is expected to be used for high-load-bearing degradable bone-implant devices, including bone fixation and guided bone regeneration systems.