Magnesium (Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair. Rare earth elements (REEs) have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys. This study methodically investigated the impacts of scandium (Sc) and terbium (Tb) in tailoring the corrosion resistance, mechanical properties, and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn (MZZM) alloys fabricated via casting and hot extrusion. Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms. The extruded MZZM–(1–2)Sc–(1–2)Tb (wt.%) alloys exhibit compressive strengths within the range of 336–405 MPa, surpassing the minimum required strength of 200 MPa for bone implants by a significant margin. Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM (0.25 mm/y), MZZM–2Tb (0.45 mm/y), MZZM–1Sc–1Tb (0.18 mm/y), and MZZM–1Sc–2Tb (0.64 mm/y), and extruded MZZM (0.17 mm/y), MZZM–1Sc (0.15 mm/y), MZZM-2Sc (0.45 mm/y), MZZM-1Tb (0.17 mm/y), MZZM-2Tb (0.10 mm/y), MZZM–1Sc-1Tb (0.14 mm/y), MZZM-1Sc-2Tb (0.40 mm/y), and MZZM–2Sc–2Tb (0.51 mm/y) alloys, which were found lower compared to corrosion rate of high-purity Mg (∼1.0 mm/y) reported in the literature. Furthermore, addition of Sc, or Tb, or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells, but enhanced their initial cell attachment, proliferation, and spreading shown via polygonal shapes and filipodia. This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys, as they effectively enhance corrosion resistance, mechanical properties, and biocompatibility simultaneously.

中文翻译：

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钪和铽对可生物降解Mg-Zn-Zr-Mn合金力学性能、腐蚀行为和生物相容性的影响

镁（Mg）基骨植入物在人体的生理环境中迅速降解，在充分的骨修复之前影响其结构完整性和生物相容性。稀土元素 (REE) 已证明其在调节镁合金的腐蚀和机械性能方面的有效性。本研究系统地研究了钪 (Sc) 和铽 (Tb) 对通过铸造和热挤压制造的 Mg–0.5Zn–0.35Zr–0.15Mn (MZZM) 合金的耐腐蚀性、机械性能和生物相容性的影响。结果表明，Sc 和 Tb 的添加通过晶粒尺寸减小和固溶强化机制提高了 MZZM 合金的强度。挤压的 MZZM–(1–2)Sc–(1–2)Tb (wt.%) 合金的抗压强度在 336–405 MPa 范围内，大大超过了骨植入物所需的最低强度 200 MPa 。动电位极化测试表明铸态 MZZM (0.25 mm/y)、MZZM–2Tb (0.45 mm/y)、MZZM–1Sc–1Tb (0.18 mm/y) 和 MZZM–1Sc–2Tb (0.64 mm) 的腐蚀速率较低/y)，以及挤压 MZZM (0.17 mm/y)、MZZM–1Sc (0.15 mm/y)、MZZM-2Sc (0.45 mm/y)、MZZM-1Tb (0.17 mm/y)、MZZM-2Tb (0.10 mm) /y)、MZZM–1Sc-1Tb (0.14 mm/y)、MZZM-1Sc-2Tb (0.40 mm/y) 和 MZZM–2Sc–2Tb (0.51 mm/y) 合金，与腐蚀速率相比较低文献中报道的高纯镁（∼1.0 mm/y）。此外，向 MZZM 合金中添加 Sc、或 Tb、或 Sc 和 Tb 不会对 SaOS2 细胞的活力产生不利影响，但通过多边形形状和丝状伪足增强了它们的初始细胞附着、增殖和扩散。这项研究强调了在 MZZM 合金中加入 Sc 和 Tb 元素的好处，因为它们可以同时有效增强耐腐蚀性、机械性能和生物相容性。