生物镁合金具有优异的生物相容性和力学相容性，但降解速率过快极大的限制了其在骨修复中的应用。本项目利用激光选区熔化技术制备纳米蜂窝结构增强的生物镁合金，其中纳米蜂窝结构是由氧化石墨烯（GO）构建的第二相，而生物镁合金晶粒包裹于蜂窝单元中，以期利用GO突出的物理屏蔽作用和力学性能提高生物镁合金的耐腐蚀性能与力学强度。研究激光多场耦合下生物镁合金的熔池形成与凝固机理，揭示成形过程中纳米蜂窝结构的形成条件及优化策略；探索GO在生物镁合金基体中的均匀分散方法，查明GO对生物镁合金显微组织和力学性能的影响规律；重点研究体液环境下GO/生物镁合金的降解行为和生物活性，分析蜂窝状第二相包裹下生物镁合金的降解速率及力学性能演变规律，揭示降解过程中纳米蜂窝结构对生物镁合金的保护机制，形成生物镁合金可控降解和力学稳定的最优结构匹配准则及其快速制造技术，为开发满足骨修复要求的生物镁合金奠定理论基础。

Biomedical magnesium alloys possess excellent biocompatibility and mechanical compatibility, but the too fast degradation rates significantly limit their application in bone repair. In this project, selective laser melting is used to fabricate honeycomb nanostructure enhanced biomedical magnesium alloys, in which the honeycomb nanostructure is a second phase constructed by graphene oxide (GO) while the grains of biomedical magnesium alloys are wrapped in the honeycomb unit, aiming to improve the corrosion resistance and mechanical strength of biomedical magnesium alloys through the prominent physical shielding effect and mechanical properties of GO. The formation of molten pool and solidification mechanism of biomedical magnesium alloys under laser multi-field coupling will be studied, and the formation conditions and optimization strategies of honeycomb nanostructure during the fabrication process will be revealed. Moreover, the uniform dispersion methods of GO in the matrix of biomedical magnesium alloy will be explored, and the effects of GO on the microstructure and mechanical properties of biomedical magnesium alloys will also be investigated. Emphasis will be put on the degradation behavior and bioactivity of GO/biomedical magnesium alloys under body fluid environment. The evolution rules of degradation and mechanical properties of biomedical magnesium alloys wrapped in honeycomb-like second phase will be analyzed. And then the protective mechanisms of the honeycomb nanostructure to biomedical magnesium alloys during the degradation process will be revealed. Based on the above research, the optimal structure matching criterions and corresponding rapid manufacturing technology for the controlled degradation and mechanical stability of biomedical magnesium alloys will be established, which may provide the theoretical basis for developing biomedical magnesium alloys that meet the requirements for bone repair.