Creation of thin TiNi wires with stabilized martensite phase

TiNi-based alloys have a unique set of functional and structural properties, which allows them to be used as materials for creating implants. Thin TiNi threads were obtained by drawing with intermediate chemical and mechanical treatments. Thinning the threads to 40-60 μm made it possible to manufacture textile implants for use in soft tissues of the human body. However, the Young's modulus (E) of metallic TiNi-based materials can exceed that of soft connective tissues. Cryogenic treatment can reduce the elastic modulus by stabilizing the martensite phase and thereby reducing the rigidity of the material. This approach is novel and helps solve a fundamental problem in medical materials science.

Thin TiNi wires were obtained through the traditional technique and cryogen treatment. X-ray diffractometry, scanning electron microscopy, and energy dispersive spectroscopy allowed for determination of the structure and phase composition of thin wires with a composite structure based on TiNi(B2), TiNi3, TiC, and TiO2 phases. It was shown that the cryogenic treatment of thin TiNi wire resulted in the formation of two phases B2+B19 in the structure, which indicated martensite stabilization after cooling. The porosity of the obtained implants was 80 to 85%. SEM images of the structure of spherical implants after biointegration show the high integration tie between these implants and animal tissues. The high integration tie was observed between body tissues both inside and on the surface of the spherical implant.

This research was financially supported by Grant No. 24-29-00735 from the Russian Science Foundation.