Medium-entropy Zr–Nb–Ti alloys with low magnetic susceptibility, high yield strength, and low elastic modulus through spinodal decomposition for bone-implant applications

作者：Zhaolin Hua, Dechuang Zhang, Lin Guo, Sihan Lin, Yuncang Li, Cuié Wen · 发表于：Acta Biomaterialia · 年份：2024 · DOI：10.1016/j.actbio.2024.11.001 · 被引用次数：28 · 研究领域：High Entropy Alloys Studies、Titanium Alloys Microstructure and Properties、Intermetallics and Advanced Alloy Properties

Medium-entropy Zr–Nb–Ti (ZNT) alloys are being extensively investigated as load-bearing implant materials because of their exceptional biocompatibility and corrosion resistance, and low magnetic susceptibility. Nevertheless, enhancing their yield strength while simultaneously decreasing their elastic modulus presents a formidable obstacle, significantly constraining their broader utilization as metallic biomaterials. In this study, three medium-entropy ZNT alloys, i.e., Zr 45 Nb 45 Ti 10 , Zr 42.5 Nb 42.5 Ti 15 , and Zr 40 Nb 40 Ti 20 (denoted ZNT 10 , ZNT 15 , and ZNT 20 , respectively), were designed based on the miscibility gap in the ZNT phase diagram and prepared by annealing of cold-rolled ingots. Their microstructures, mechanical properties, wear resistance, corrosion resistance, magnetic susceptibility, and biocompatibility were systematically studied. Spinodal decomposition occurred in the cold-rolled ZNT 10 and ZNTi 15 after annealing at 650°C for 2 h and resulted in nanoscale Zr-rich β 1 and (Nb, Ti)-rich β 2 phases, which significantly improved their yield strength and reduced their elastic modulus. The wear resistance of the alloys decreased with an increase in Ti content. Dense ZrO 2 , Nb 2 O 5 , and TiO 2 oxide layers were formed during the polarization process in Hanks’ solution, which enhanced the corrosion resistance of the alloys. These ZNT alloys exhibited significantly lower magnetic susceptibility than medical Ti alloys. The ZNT alloys showed a cell viab...