Characteristics of the superelastic recovery of thermomechanically treated wire composed of alloy Ti–50.7% Ni for use in a stapler employed to reconnect blood vessels

• Published in: Metallurgist (New York) 2010-09, Vol.54 (5-6), p.401-406
• Main Authors: Prokoshkin, S. D., Khmelevskaya, I. Yu, Ryklina, E. P., Suturin, M. V., Chernov, A. N., Chernavina, A. A., Krasnoshchekov, M. V.
• Format: Article
• Language: English
• Subjects: Alloy development; Alloys; Blood vessels; Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Metallic Materials; Recovery; Staples; Superelasticity; Tempering; Titanium base alloys; Wire
• ISSN: 0026-0894; 1573-8892
• DOI: 10.1007/s11015-010-9308-z

The aortic-coronary shunting procedure developed by Dr. M. V. Suturin with the aid of a unique stapler designed by the company Endogene makes it possible to reconnect blood vessels with staples made of a superelastic Ti–Ni alloy while the heart is still working (without its stoppage). The use of proprietary methods for post-deformation annealing of the wire used to make the staples makes it possible to obtain the best possible functional properties. The difference between the dislocation- and phase-based yield points is Δσ = 900 MPa. The average critical stress associated with superelastic recovery is 1.5–2 times greater after low-temperature thermomechanical treatment than after warm drawing. Fully reversible deformation reaches a maximum of P r1 max = 6.5%, while the maximum force obtained with the staples is P r se = 6.5 N. The high functionality of the staples is proven by the fact that they recover more than 90% of their initial shape. Storage of the staples in the stapler in the straightened state for 1 month has no effect on the degree of shape recovery.