Development of TiNi Alloy Superelastic Guidewire Needle for New Type of Medical Arthroscopic Surgery

This research focuses on the development of TiNi alloy super elastic guide needles for new medical arthroscopic surgery. With the development of sports medicine and the increasing demand for minimally invasive arthroscopic surgeries, the limitations of traditional surgical needles have become more prominent. TiNi shape - memory alloy (SMA) has unique super elasticity, shape - memory effect, and excellent mechanical properties, making it suitable for manufacturing super elastic suture needles. The project aimed to develop high - performance nickel - rich Ti - 50.8Ni - 0.4V SMA. The preparation process included designing alloys, melting into ingots, hot forging, rolling, and heat treatment. Various experimental methods were used, such as SEM, OM, DSC, TEM, and tensile testing, to analyze the phase transformation temperature, phase composition, microstructure, and super elastic properties of the alloys under different processing conditions. The results showed that for NiTi alloy wires, when annealed at 400 - 600 °C, as the heat - treatment temperature increased, the critical stress for stress - induced martensitic transformation decreased, the residual strain after tensile testing increased, and the super elasticity decreased significantly. When aged at 500 °C, with the prolongation of aging time, similar changes occurred. In the cyclic stress - strain curves, as the heat - treatment temperature increased, the residual strain of the wire increased, indicating a greater loss of super elasticity. However, wires annealed at 400 - 450 °C showed good continuous super elasticity. Also, the fatigue performance test of the alloy showed a fatigue life of more than 88,800 cycles under a stress of 200 MPa, with low energy loss and little impact on accuracy during use. In conclusion, low - temperature and short - time heat treatment is beneficial for obtaining good superelasticity of the alloy. The research provides a theoretical basis and experimental support for the actual production and application of superelastic guide needles with high strength and superelasticity for low - temperature use in arthroscopic surgeries.