Paper Title:

Creation of Superelastic Functional Properties in a Ti-50.7%Ni Wire for the Stapler Suturing of Blood Vessels

Periodical Advances in Science and Technology (Volume 76)
Main Theme 5th FORUM ON NEW MATERIALS PART E
Edited by Pietro VINCENZINI, John A. JANSEN, Kazuhiko ISHIHARA and Thomas J. WEBSTER
Pages 253-258
DOI 10.4028/www.scientific.net/AST.76.253
Citation I. Khmelevskaya et al., 2010, Advances in Science and Technology, 76, 253
Online since October, 2010
Authors I. Khmelevskaya, M. Soutorine, S. Prokoskin, E. Ryklina
Keywords Functional Property, Stapler, Superelastic Staple, Thermomechanical Treatment (TMT)
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Abstract

The technique of aorta-coronary shunting offered by Dr. M. Soutorine by means of the original stapler developed by "Endogene" allows suturing blood vessels by superelastic Тi-Ni staples on «working heart» (without heart switching-off). The material for staples is a 0.30 and 0.315 mm diam. wire which was studied by DSC, shape recovery and mechanical tests. Thermomechanical treatment (TMT) comprised warm drawing, low- temperature (LTMT) by cold drawing with 25-30% strain in the last pass and following post-deformation annealing (PDA). LTMT leads to increasing of yield stress in comparison with warm drawing. Treatment of wire under LTMT+PDA allows obtaining the highest characteristics of functional properties of the wire. The difference between “dislocation” and “transformation” yield stresses  Δ=900 MPa. Critical stress of superelastic recovery after TMT on the average is 1.5-2 times higher in comparison with warm drawing. The maximum completely recoverable strain r,1max=6.5%. The maximum obtained force value of staples is РrSE=6.5 Н. The shape recovery rate of staples was 85-97 % that provided its functionality. Storage in the stapler in straightened condition within 1 month does not worse the staples.