Advancing biodegradable medical implants, along with an in-depth understanding of their degradation mechanisms, is critical to revolutionizing orthopedic medicine and improving patient outcomes. MgZnCa metallic glass (MG) stands out among degradable metallic materials due to its superior potential for orthopedic applications than traditional crystalline alloys. Despite its advantages, there has been a lack of comprehensive insight into the degradation behavior of MgZnCa MG, particularly under conditions simulating daily activities of patients. In this work, the degradation mechanism of MgZnCa MG is elucidated, highlighting the formation of a distinctive Zn-rich amorphous layer that markedly decelerates the matrix degradation. Detailed analysis reveals that the unique amorphous structure of MgZnCa MG facilitates the selective dissolution of Mg and Ca, resulting in numerous vacancies within the matrix. These vacancies facilitate the inward migration of Zn atoms, culminating in the formation of a dense Zn-rich layer. This cyclical formation and dissolution of the Zn-rich layer serve as a buffer in the degradation pathway, thus ensuring a degradation rate for MgZnCa MG that is significantly slower than that of its crystalline counterparts.

中文翻译：

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调控 MgZnCa 金属玻璃的降解：通过锌内部迁移形成富锌非晶层


推进可生物降解的医疗植入物，以及深入了解其降解机制，对于彻底改变骨科医学和改善患者预后至关重要。MgZnCa 金属玻璃 （MG） 在可降解金属材料中脱颖而出，因为它比传统的结晶合金在骨科应用中具有更大的潜力。尽管具有优势，但人们对 MgZnCa MG 的降解行为缺乏全面的了解，尤其是在模拟患者日常活动的条件下。在这项工作中，阐明了 MgZnCa MG 的降解机制，突出了独特的富锌无定形层的形成，该层显着减慢了基质降解。详细分析表明，MgZnCa MG 独特的无定形结构促进了 Mg 和 Ca 的选择性溶解，导致基质内出现许多空位。这些空位促进了 Zn 原子的向内迁移，最终形成致密的富 Zn 层。富锌层的这种循环形成和溶解作为降解途径中的缓冲剂，从而确保 MgZnCa MG 的降解速率明显慢于其晶体对应物。