Advanced Manufacturing Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-2-1 Namiki, Tsukuba, Ibaraki 305-8564, Japan.
Mater Sci Eng C Mater Biol Appl. 2013 Dec 1;33(8):4746-50. doi: 10.1016/j.msec.2013.07.033. Epub 2013 Jul 27.
Though Mg alloys are promising candidates for biodegradable stents, it is very difficult to fabricate stent tubes with high dimensional accuracy using Mg alloys because of their low deformability. This study aimed to develop thin-walled, high-quality Mg alloy tubes with good performance in stent applications. Cold drawing with a fixed mandrel was carried out for extruded Mg-0.8%Ca and AZ61 alloy tubes using optimized drawing parameters and lubrication, and stent tubes with 1.5-1.8mm outer diameter and 150 μm thickness were fabricated. A dimensional evaluation showed that the tube dimensional errors were within 0.02-2.5%. Also, an immersion test of pure Mg with different crystal orientations showed that the crystal orientation affected the corrosion properties, results that are the same with other Mg alloys. The crystal orientation of the stent tube could be controlled by changing the deformation amount and direction in the drawing, showing that it is possible to further improve the biodegradability of stents by approaching their fabrication from a processing aspect.
虽然 Mg 合金是很有前途的可生物降解支架候选材料，但由于其变形能力低，很难用 Mg 合金制造具有高精度尺寸的支架管。本研究旨在开发具有薄壁、高质量和良好支架应用性能的 Mg 合金管。使用优化的拉拔参数和润滑剂对挤压 Mg-0.8%Ca 和 AZ61 合金管进行冷拉拔，制造出外径为 1.5-1.8mm、厚度为 150μm 的支架管。尺寸评估表明，管的尺寸误差在 0.02-2.5%以内。此外，不同晶向纯 Mg 的浸泡试验表明，晶向影响腐蚀性能，这与其他 Mg 合金的结果相同。支架管的晶向可以通过改变拉拔过程中的变形量和方向来控制，这表明可以通过从加工方面来进一步提高支架的生物降解性。
