不同构型Mg-5Zn镁合金多孔骨修复支架SLM成形质量与性能

Effect of Pore Structure on Forming Quality and Performance of Mg-5Zn Magnesium Alloy Porous Bone Repair Scaffold Fabricated by SLM

摘要:

设计并通过激光选区熔化技术制备了体心立方型（bcc）、菱形十二面体（RD）、螺旋型（G）和简单立方型（P）四种Mg-5Zn多孔支架，研究了其成形质量、压缩力学性能和降解行为。结果表明，所制备的支架具有较好的还原度，表面化学抛光处理显著改善了支架成形质量，并降低多孔支架的孔隙误差。面结构（G，P）支架粘附粉末的程度较杆结构（bcc，RD）轻，成形误差较小。相同设计孔隙率下，G构型支架的成形质量最佳。压缩时支架的失效模式以45°剪切断裂为主。孔隙率为75%时，四种构型支架的压缩性能都满足松质骨的压缩性能要求，bcc和G构型支架压缩性能相对较好。Hank's溶液浸泡168 h后，B-2-75%构型支架局部腐蚀较为严重，部分支柱连接处发生断裂；G-3-75%构型支架以均匀腐蚀为主，结构保持较为完整，腐蚀速率和压缩性能损失小于B-2-75%结构。经综合对比，优选G构型。

Abstract:

Four types of Mg-5Zn porous scaffolds with different pore geometries, including body-centered cubic (bcc), the rhombic dodecahedron (RD), gyroid (G), and primitive (P) types, were designed and fabricated using selective laser melting. Their forming quality, compression mechanical properties, and degradation behavior were investigated. Results indicate that the fabricated scaffolds exhibit good dimensional accuracy, and the surface chemical polishing treatment significantly improves the forming quality and reduces porosity error in porous scaffolds. Compared to the ones with rod structures (bcc, RD), the scaffolds with surface structures (G, P) have less powder particle adhesion. The G porous scaffold exhibits the best forming quality for the same design porosity. The predominant failure mode of scaffolds during compression is a 45° shear fracture. At a porosity of 75%, the compression property of all scaffolds meets the compressive property requirements of cancellous bone, while bcc and G structures show relatively better compression property. After immersion in Hank's solution for 168 h, the B-2-75% pore structure scaffold exhibits severe localized corrosion, with fractures in partial pillar connections. In contrast, the G-3-75% pore structure scaffold mainly undergoes uniform corrosion, maintaining structural integrity, and its corrosion rate and loss of compressive properties are less than those of the B-2-75% structure. After comparison, the G-pore structure scaffold is preferred.