骨植入用铸态Mg-Ga合金的力学性能、生物降解行为及细胞相容性

Mechanical Properties,Biodegradation Behavior,and Cytocompatibility of As-Cast Mg-Ga Alloys for Bone Implant Applications

研究了铸态Mg-2Ga和Mg-5Ga合金的力学性能、生物腐蚀行为、细胞相容性与其微观组织结构的变化关系。采用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对材料的微观组织结构进行了分析。结果表明:添加Ga元素后,在镁基体的晶界上形成了球状和带状的Mg_(5)Ga_(2)析出相,Ga元素显著细化了镁基体的晶粒尺寸。力学拉伸试验结果表明,Ga元素可通过固溶强化、晶界强化、析出强化等作用提高Mg-Ga合金的力学性能。在37℃模拟体液中的电化学腐蚀和浸泡腐蚀试验结果表明,低Ga含量能够提高Mg-Ga合金的表面稳定性,从而改善其腐蚀行为。此外,间接接触细胞培养试验结果表明,Mg-2Ga与Mg-5Ga合金均对小鼠成纤维细胞(L929)表现出良好的细胞相容性,未对其产生明显的细胞毒性。

The microstructures, mechanical properties, biodegradation behavior, and cytocompatibility of the as-cast Mg-2Ga and Mg-5Ga alloys were investigated. The microstructure characteristics were studied by X-ray diffractometer(XRD) and scanning electron microscopy(SEM). The results show that the Mg_(5)Ga_(2)precipitates with globular and strip-like shapes are formed along the grain boundaries in Mg matrix after Ga addition. The grains of Mg-Ga alloys are obviously refined by Ga addition. The tensile tests reveal that the mechanical properties of Mg-Ga alloys are enhanced by Ga addition via solution strengthening, grain boundary strengthening, and precipitation strengthening. The electrochemistry and immersion corrosion tests in simulated body fluid at 37 ℃ reveal that the improved corrosion behavior is attributed to the enhanced surface stability caused by Ga addition of low content. In addition, the indirect contact assay suggests that both Mg-2Ga and Mg-5Ga alloys exhibit favorable cytocompatibility with no cytotoxicity for the mouse fibroblast(L929) cells.