医用稀土镁合金微观组织特征及力学行为研究进展

Research Progress on Microstructure and Mechanical Properties of Medical Rare-Earth Magnesium Alloys

摘要:

近年来，镁合金作为生物医用金属材料受到了广泛关注，但其较差的力学强度极易导致植入物在服役周期内崩塌断裂，严重危及患者生命安全。稀土微复合金化作为当下提高可降解镁合金力学性能的有效措施，在消除镁合金杂质元素、净化熔体的同时，还可以起到促进动态再结晶、形成长周期堆垛有序相等作用。因此，本文从稀土镁合金微观结构转变及其与力学性能的基本关联出发，综述了近年来医用稀土镁合金组织特征及力学性能的研究进展，深入发掘了稀土元素、第二相及镁合金力学性能之间的本质关联，详细阐述了连续动态再结晶对稀土镁合金的强韧化机理，全面叙述了稀土元素诱导长周期堆垛有序结构对镁合金力学性能的影响规律。最后，本文对医用稀土镁合金未来的发展方向进行了展望。

Abstract:

Recently, magnesium alloys attract much more attention as the biomedical metallics. Unfortunately, due to their low strength, the implantation materials of Mg alloys are prone to collapse and fracture during the in-vivo/vitro service, which seriously endangers the life-safety of patients. Rare-earth micro-alloying is an effective method to enhance the mechanical properties of degradable Mg-based alloys, which cannot only eliminate the impurities and purify the melt, but also promote the dynamic recrystallization and form the long period stacking ordered phase structure. Therefore, based on the correlations between mechanical properties and microstructure transformation of Mg alloys, the research progress on the microstructure and mechanical properties of rare-earth Mg alloys was reviewed. The essential correlations among the rare-earth elements, the secondary phases, and the mechanical properties of Mg alloys were investigated. Additionally, the strengthening and toughening mechanisms of the continuous dynamic recrystallization of medical rare-earth Mg alloys were clarified. Besides, the effect of long-period stacking ordered structure induced by rare-earth elements on the mechanical properties of Mg alloys was comprehensively summarized. Finally, the development directions of medical rare-earth Mg alloys was proposed.