Scholarlink

<p>The key to successful transcatheter aortic valve replacement (TAVR) lies in the development of the aortic valve stent. Due to its unique shape memory effect and superelasticity, NiTi shape memory alloy has become the mainstream self-expanding stent material. Given the high-temperature sensitivity of NiTi alloys, precise control over the heat treatment process is critical to enhance performance stability and ensure reliable service life. This study explores a two-stage aging heat treatment process for the NiTi alloy material used in transcatheter aortic valve stents. The first stage of aging treatment was performed at temperatures ranging from 370 to 430 °C (in 30 °C intervals, for durations between 8 and 60 min) to optimize the microstructure for stable superelastic performance. The second stage was conducted at temperatures between 500 and 550 °C (in 25 °C intervals, for durations between 5 and 60 min) to shape the NiTi alloy to the desired service geometry. This work systematically investigates the influence of the two-stage aging process on microstructural evolution, phase composition, phase transformation behavior, and mechanical properties of the material. The results indicate that the optimized first-stage aging parameters (400 °C-60&#xa0;min) maximized martensite content while achieving 40% elongation. For the second stage, the optimal parameters are 500 °C for 5 min, producing NiTi alloy with good superelasticity, meeting the requirements for stent applications.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Effect of Two-Stage Aging Heat Treatment on the Properties of NiTi Alloy for Transcatheter Aortic Valve Stents

  • 期刊论文

  • 发表日期：

    2025年9月26日

查看全文
  • Zipeng Wang,
  • Zherong Huang,
  • Kaikun Wang,
  • Jianye Zhou

摘要

The key to successful transcatheter aortic valve replacement (TAVR) lies in the development of the aortic valve stent. Due to its unique shape memory effect and superelasticity, NiTi shape memory alloy has become the mainstream self-expanding stent material. Given the high-temperature sensitivity of NiTi alloys, precise control over the heat treatment process is critical to enhance performance stability and ensure reliable service life. This study explores a two-stage aging heat treatment process for the NiTi alloy material used in transcatheter aortic valve stents. The first stage of aging treatment was performed at temperatures ranging from 370 to 430 °C (in 30 °C intervals, for durations between 8 and 60 min) to optimize the microstructure for stable superelastic performance. The second stage was conducted at temperatures between 500 and 550 °C (in 25 °C intervals, for durations between 5 and 60 min) to shape the NiTi alloy to the desired service geometry. This work systematically investigates the influence of the two-stage aging process on microstructural evolution, phase composition, phase transformation behavior, and mechanical properties of the material. The results indicate that the optimized first-stage aging parameters (400 °C-60 min) maximized martensite content while achieving 40% elongation. For the second stage, the optimal parameters are 500 °C for 5 min, producing NiTi alloy with good superelasticity, meeting the requirements for stent applications.