可生物降解镁合金是医用金属材料的前沿方向，而多孔结构可进一步改善其生物和力学相容性。本项目提出采用固/气共晶定向凝固(Gasar工艺)制备镁合金规则多孔结构，实现生物和力学相容。选取典型可生物降解镁合金Mg-M(M=Zn,Mn,Ca)二元系作为研究对象，重点解决镁合金在Gasar凝固过程中糊状区枝晶与气泡相互作用机制、气泡形貌与凝固界面形貌关系、结构参数理论预测等关键科学问题。理论和实验相结合，系统研究制备工艺参数、合金化元素种类及加入量对镁合金多孔体的气孔形貌、气孔率以及气孔尺寸的影响规律，最终通过工艺参数的调节实现对气孔形貌、大小和分布的主动控制。在获得镁合金规则多孔结构基础上，研究其弹性模量、压缩强度和弯曲强度等力学性能与气孔率、孔径、形貌以及分布的关系。该项目的开展对于推动我国可降解镁合金生物医用材料的应用以及Gasar凝固理论的发展具有重要作用。

Biodegradable Mg-based alloy is a new frontier of biomedical materials and porous structure can further improve its biocompatibility and mechanical compatibility. In order to achieve a better biocompatibility and mechanical compatibility, this project will first make an attempt to fabricate regular porous Mg-based biodegradable alloys by the solid/gas eutectic directional solidification (Gasar process). Through practical Gasar solidification experiment of Mg-M(M=Zn,Mn,Ca) alloys, this project will focused on these key scientific items including the solidification interface/gas bubble interaction mechanism, pores structural control and theoretical prediction of porous structural parameters in Gasar solidification of magnesium alloys. Combining theoretical analysis and fabrication experiments, this project will systematically investigate influence of the processing parameters, adding content of different alloying elements on pore morphology, size and distribution, finally achieve the fabrication of biodegradable porous Mg-based alloys and active control of porous structural parameters. After that, the influence of porous structural parameters on the mechanical properties including the elastic modulus and the compression strength of porous Mg-M(M=Zn,Mn,Ca) alloys will be investigated systematically. These research contents will make a strong foundation for the biodegradable Mg-based alloys' application in the reparation and promote the development of solidification theory.