S and B microalloying of biodegradable Fe-30Mn-1C - Effects on microstructure, tensile properties, in vitro degradation and cytotoxicity
S and B microalloying of biodegradable Fe-30Mn-1C - Effects on microstructure, tensile properties, in vitro degradation and cytotoxicity
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DOI：
10.1016/j.matdes.2018.01.005
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发表时间：
2018-03
影响因子：
8.4
通讯作者：
J. Hufenbach;F. Kochta;H. Wendrock;A. Voß;L. Giebeler;S. Oswald;S. Pilz;U. Kühn;A. Lode
中科院分区：
文献类型：
--
作者：
J. Hufenbach;F. Kochta;H. Wendrock;A. Voß;L. Giebeler;S. Oswald;S. Pilz;U. Kühn;A. Lode
奥氏体Fe-Mn-C基合金具有较高的强度、延展性和降解过程中的机械完整性，被认为是可生物降解血管植入物的理想候选材料，本研究表明，添加S和B的微合金化是一种有效的方法，可以进一步提高Fe-30 Mn-1C孪晶诱导塑性（TINNING诱导塑性，TINNING诱导塑性）合金的降解速率和力学性能，同时不降低其生物相容性。为了研究由于S或B的加入而引起的微观结构变化，通过X射线衍射（XRD）以及扫描电子显微镜（SEM）结合能量色散X射线光谱（EDX）、波长色散X射线分析（WDX）和电子背散射衍射（EBSD）来分析合金。因此，在奥氏体基体中检测到（Fe 0.3Mn 0.7）S和（Fe，Mn）23（C3 B3）类型的沉淀物。这些析出物不仅对拉伸载荷下的机械性能，而且对发生的腐蚀机制具有明显的影响。通过动电位极化测量和模拟体液（SBF）中的浸泡试验以及相关的SEM和X射线光电子能谱（XPS）研究显示了这一点。L929成纤维细胞的体外细胞毒性试验表明，S和B的加入并不影响合金的细胞相容性，因此，新型合金改性材料作为生物可降解植入材料具有很高的应用前景。
Austenitic Fe-Mn-C-based alloys are considered as promising candidates for biodegradable vascular implants due to their high strength, ductility and mechanical integrity during degradation.The present study demonstrates that microalloying with S and B is an effective method to further enhance the degradation rate and the mechanical properties of a Fe-30Mn-1C twinning-induced plasticity (TWIP) alloy without deteriorating the biocompatibility. For studying the microstructural changes due to S or B addition, the alloys were analysed by X-ray diffraction (XRD) as well as scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDX), wavelength dispersive X-ray analysis (WDX) and electron backscatter diffraction (EBSD). Thereby precipitates of (Fe0.3Mn0.7)S and (Fe,Mn)23(C3B3) types were detected in the austenitic matrix. These precipitates have a distinct influence not only on the mechanical properties under tensile load but also on the occurring corrosion mechanism. This was displayed by potentiodynamic polarization measurements and immersion tests in simulated body fluid (SBF) and associated SEM as well as X-ray photoelectron spectroscopy (XPS) investigations. In vitro cytotoxicity analyses with L929 fibroblast cells indicated that microalloying with S and B does not affect the cytocompatibility.Thus, the novel alloy modifications show a high potential for future application as biodegradable implant material.