Fabrication and characterization of biodegradable Zn-Cu-Mn alloy micro-tubes and vascular stents: Microstructure, texture, mechanical properties and corrosion behavior
Fabrication and characterization of biodegradable Zn-Cu-Mn alloy micro-tubes and vascular stents: Microstructure, texture, mechanical properties and corrosion behavior
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DOI：
10.1016/j.actbio.2022.07.049
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发表时间：
2022-09-29
影响因子：
9.7
通讯作者：
Yuan, Guangyin
中科院分区：
文献类型：
--
作者：
Jiang, Jimiao;Huang, Hua;Yuan, Guangyin
锌合金是一种很有前途的可生物降解血管支架材料。本研究旨在制备具有高尺寸精度和合适力学性能的可生物降解Zn-2.0Cu-0.5Mn合金微管和血管支架，并研究其显微组织、织构、力学性能和腐蚀行为。采用挤压、拉伸、激光切割和电化学抛光等工艺成功制备了微管道和血管支架。挤压态和拉拔态微管的显微组织均由Zn基体和不同尺寸的CuZn 4和MnZn 13第二相组成，Zn基体为近等轴晶（平均晶粒尺寸约为2 μ m）。由于变形机制由挤压时的基底位错滑移转变为拉拔时的棱柱< a >< a >位错、锥状< c + a >位错和{ 10 1 over bar 2 }孪晶，使得织构由挤压态的近似平行于变形方向的基面演变为拉拔态的近似垂直于变形方向的基面。作为支架材料，拉伸后的微管表现出合适的机械性能，极限拉伸强度为约298 MPa，伸长率为约26%。此外，具有约125 μ π ι的厚度的经处理的支架具有约150 kPa的足够的径向强度和良好的球囊扩张性。此外，拉制管的体外腐蚀速率约为158 μ m/年，腐蚀形貌基本均匀。结果表明，可生物降解的Zn-2.0Cu-0.5Mn合金是一种很有前途的血管支架材料候选者，该工艺制备的微管和支架是可行和有效的。
Zinc (Zn) alloys are a promising biodegradable material for vascular stent applications. This study aimed to fabricate biodegradable Zn-2.0Cu-0.5Mn alloy micro-tubes and vascular stents with high dimensional accuracy and suitable mechanical properties, and to investigate their microstructure, texture, mechanical properties and corrosion behavior. The micro-tubes and vascular stents were successfully fabricated by a combined process of extrusion, drawing, laser cutting and electrochemical polishing. The microstruc-tures of as-extruded and as-drawn micro-tubes consisted of Zn matrix with near-equiaxed grains (aver-age grain size: similar to 2 pm) and second phases of epsilon (CuZn4) and MnZn13 with different sizes. The texture evolved from basal planes approximately paralleling to deformation direction for as-extruded micro-tube to approximately perpendicular to deformation direction for as-drawn micro-tube, because predominant deformation mechanisms changed from basal < a > dislocation slip during tube extrusion to prismatic < a > dislocation, pyramidal < c + a > dislocations, and { 10 1 over bar 2 } twins during tube drawing. As-drawn micro -tube exhibited suitable mechanical properties with an ultimate tensile strength of about 298 MPa and elongation of about 26% as a stent material. Moreover, the processed stent with a thickness of about 125 pm possessed sufficient radial strength of about 150 kPa and good balloon expandability. In addi-tion, as-drawn tube exhibited an in vitro corrosion rate of about 158 pm/year with a basically uniform corrosion morphology. These results indicated that biodegradable Zn-2.0Cu-0.5Mn alloy is a promising vascular stent material candidate, and the procedure for processing the micro-tube and stent is practical and effective.