Novel Zn-based alloys for biodegradable stent applications: Design, development and in vitro degradation
Novel Zn-based alloys for biodegradable stent applications: Design, development and in vitro degradation
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DOI：
10.1016/j.jmbbm.2016.03.018
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发表时间：
2016-07-01
影响因子：
3.9
通讯作者：
Vedani, M.
中科院分区：
文献类型：
--
作者：
Mostaed, E.;Sikora-Jasinska, M.;Vedani, M.
寻找一种可降解的金属，同时显示出与不锈钢相同或更高的机械性能和均匀的降解仍然是一个开放的挑战。已经研究了几种镁基合金，但它们的降解速度太快，而且很少均匀。铁基合金表现出适当的机械性能，但降解率非常低。在本工作中，四个新的锌镁和两个锌铝二元合金作为潜在的可生物降解材料的支架应用进行了研究。通过铸造工艺开发合金，并在350 ° C下均质化48小时，随后在250 ° C下热挤出。在300 ° C下进行管挤出，以生产外径/内径为4/1.5 mm的管，作为可生物降解支架的前体。使用Hanks改良溶液进行腐蚀试验。挤压合金表现出略优于上级耐腐蚀性和较慢的降解速率比他们的铸造同行，但所有的腐蚀速率约一半的标准纯度镁控制。锌镁合金的热挤压转变的腐蚀制度从局部点蚀更均匀的侵蚀，主要是由于第二相粒子的细化。Zn-0.5Mg是用于支架应用的最有前途的材料，具有强度、延展性、应变硬化指数和降解期间机械完整性的适当损失率的良好组合。在激光切割的Zn-0.5Mg管附近进行的EBSD分析未发现晶粒粗化或纹理改性，证实激光切割后，最终支架的晶粒尺寸和纹理取向保持不变。这项工作显示了锌合金被认为是支架应用的潜力。(C)2016爱思唯尔有限公司版权所有。
The search for a degradable metal simultaneously showing mechanical properties equal or higher to that of stainless steel and uniform degradation is still an open challenge. Several magnesium-based alloys have been studied, but their degradation rate has proved to be too fast and rarely homogeneous. Fe-based alloys show appropriate mechanical properties but very low degradation rate. In the present work, four novel Zn-Mg and two Zn-Al binary alloys were investigated as potential biodegradable materials for stent applications. The alloys were developed by casting process and homogenized at 350 degrees C for 48 h followed by hot extrusion at 250 Tube extrusion was performed at 300 degrees C to produce tubes with outer/inner diameter of 4/1.5 mm as precursors for biodegradable stents. Corrosion tests were performed using Hanks' modified solution. Extruded alloys exhibited slightly superior corrosion resistance and slower degradation rate than those of their cast counterparts, but all had corrosion rates roughly half that of a standard purity Mg control. Hot extrusion of Zn-Mg alloys shifted the corrosion regime from localized pitting to more uniform erosion, mainly due to the refinement of second phase particles. Zn-0.5Mg is the most promising material for stent applications with a good combination of strength, ductility, strain hardening exponent and an appropriate rate of loss of mechanical integrity during degradation. An EBSD analysis in the vicinity of the laser cut Zn-0.5Mg tube found no grain coarsening or texture modification confirming that, after laser cutting, the grain size and texture orientation of the final stent remains unchanged. This work shows the potential for Zn alloys to be considered for stent applications. (C) 2016 Elsevier Ltd. All rights reserved.