Development, Characterisation, and Modelling of Processability of Nitinol Stents using Laser Powder Bed Fusion
Development, Characterisation, and Modelling of Processability of Nitinol Stents using Laser Powder Bed Fusion
复制标题
DOI：
10.1016/j.jallcom.2022.164681
复制
发表时间：
2022-03
影响因子：
6.2
通讯作者：
P. Jamshidi;C. Panwisawas;E. Langi;S. Cox;Ji-Ling Feng;Liguo Zhao;Moataz M. Attallah
中科院分区：
文献类型：
--
作者：
P. Jamshidi;C. Panwisawas;E. Langi;S. Cox;Ji-Ling Feng;Liguo Zhao;Moataz M. Attallah
定制血管或外周支架的增材制造（AM）对于外科医生和患者具有巨大的潜力，使患者能够具有定制的支架并从支架植入手术中获得更好的结果，具有具有资源高效的制造过程的进一步优势。在这项研究中，研究了超弹性镍钛基形状记忆合金（镍钛诺）支架的AM潜力。研究了两种用于治疗下肢复杂性外周动脉狭窄的支架设计。研究了两种支架设计的激光粉末床融合（LPBF），以研究工艺参数对支架几何形状、支柱尺寸、结构完整性和相变的影响。该研究证明了通过LPBF成功制造镍钛合金支架，支柱尺寸范围为250 µm至560 µm。支架的弹性模量在56 - 73 GPa之间，与标准奥氏体镍钛诺的弹性模量匹配良好。使用化学蚀刻来减小支柱直径并去除部分熔融的颗粒。结果表明，激光能量输入在控制Ni蒸发和随后的转变温度变化以及支架的形态方面具有至关重要的作用。较低的能量输入导致Ni蒸发减少，除了产生良好的构建形态之外，还将奥氏体完成温度保持在预期范围内。
Additive manufacturing (AM) of customised vascular or peripheral stents is of great potential for surgeons and patients, enabling the patients to have customised stents and achieving better outcomes from stenting procedures, with further advantages of having a resource efficient manufacturing process. In this study, the potential for AM of superelastic NiTi-based shape memory alloy (Nitinol) stents was investigated. Two stent designs, which are used for the treatment of complex peripheral artery stenosis in the lower limbs, were studied. Laser Powder Bed Fusion (LPBF) of two stent designs was studied to investigate the impact of the process parameters on the stent geometry, strut size, structural integrity and the phase transformations. The study demonstrated the successful manufacture of Nitinol stents via LPBF, with strut sizes in the range between 250 µm and ≈ 560 µm. The elastic modulus of the stents was between 56 and 73 GPa, which matches well with the elastic modulus of standard austenitic Nitinol. Chemical etching was used to reduce the strut diameter and to remove the partially melted particles. It was shown that the laser energy input has a vital role in controlling the Ni-evaporation and the subsequent changes in the transformation temperatures, as well as the morphology of the stents. The lower energy input results in a reduced Ni-evaporation, maintaining the austenite finish temperature at the expected range, in addition to generating a good build morphology.