The influence of grain size on the ductility of micro-scale stainless steel stent struts

  • B. P. Murphy
  • H. Cuddy
  • F. J. Harewood
  • T. Connolley
  • P. E. McHugh
Article

Abstract

Vascular stents are used to restore blood flow in stenotic arteries, and at present the implantation of a stent is the preferred revascularisation method for treating coronary artery disease, as the introduction of drug eluting stents (DESs) has lead to a significant improvement in the clinical outcome of coronary stenting. However the mechanical limits of stents are being tested when they are deployed in severe cases. In this study we aimed to show (by a combination of experimental tests and crystal plasticity finite element models) that the ductility of stainless steel stent struts can be increased by optimising the grain structure within micro-scale stainless steel stent struts. The results of the study show that within the specimen size range 55 to 190 μ m ductility was not dependent on the size of the stent strut when the grain size maximised. For values of the ratio of cross sectional area to characteristic grain length less than 1000, ductility was at a minimum irrespective of specimen size. However, when the ratio of cross sectional area to characteristic grain length becomes greater than 1000 an improvement in ductility occurs, reaching a plateau when the ratio approaches a value characteristic of bulk material properties. In conclusion the ductility of micro-scale stainless steel stent struts is sensitive to microstructure and can be improved by reducing the grain size.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    E. J. TOPOL, New Engl. J. Med. 339 (1998) 1702.CrossRefGoogle Scholar
  2. 2.
    A. HALKIN and G. W. STONE, J. of Interventional Cardiology 17 (2004) 271.Google Scholar
  3. 3.
    R. T. VAN DOMBURG, P. A. LEMOS, J. M. TAKKENBERG, T. K. K. LIU and L. A. VAN HERWERDEN, et al., Eur. Heart J. 2005 (in press).Google Scholar
  4. 4.
    G. SIANOS, S. HOFMA, J. M. R. LIGTHART, F. SAIA, A. HOYE, P. A. LEMOS and P. W. SERRUYS, Catherization and Cardiovascular Interventions 61 (2004) 111.Google Scholar
  5. 5.
    D. R. HOLMES and D. J. KEREIAKES, Reviews in Cardiovascular Medicine 6(Suppl. 1) (2005) 31.Google Scholar
  6. 6.
    B. P. MURPHY, P. SAVAGE, P. E. MCHUGH and D. F. QUINN, Ann. Biomed. Eng. 31 (2003) 686.CrossRefGoogle Scholar
  7. 7.
    J. PACHE, A. KASTRATI, J. MEHILLI, H. SCVHLEN, F. DOTZER and J. HAUSLEITER, et al., Journal of the American College of Cardiology 41 (2003) 1283.Google Scholar
  8. 8.
    A. KASTRATI, J. MEHILLI, J. DIRSCHINGER, F. DOTZER and H. SCVHLEN, et al. Circulation 103 (2001) 2816.Google Scholar
  9. 9.
    S. Z. H. RITTERSMA, R. J. DE WINTER, K. T. KOCH, M. BAX and C. E. SCHOTBORGH, et al. American Journal of Cardiology 93 (2004) 477.CrossRefGoogle Scholar
  10. 10.
    C. SIMON, J. C. PALMAZ and E. A. SPRAGUE, Journal of Long-Term Effects of Medical Implants 10(1/2) (2000) 143.Google Scholar
  11. 11.
    P. W. SERRUYS and M. J. B. KUTRYK, in “Handbook of Coronary Stents” (Martin Dunitz Ltd., London 2000)Google Scholar
  12. 12.
    D. MÖLLER, W. REIMERS, A. PYZALLA and A. FISCHER, J. Biomed. Mater. Res. 58 (2001) 69.Google Scholar
  13. 13.
    Y. KOHNO, A. KOHYAMA, M. L. HAMILTON, T. HIROSE, Y. KATOH and F. A. GARNER, J. Nucl. Mater. 283–287 (2000) 1014.Google Scholar
  14. 14.
    P. SAVAGE, B. P. O'DONNELL, P. E. MCHUGH, B. P. MURPHY and D. F. QUINN, Ann. Biomed. Eng. 32 (2004) 202.CrossRefGoogle Scholar
  15. 15.
    C. MEYER-KOBBE and B. H. HINRICHS, Medical Device Technology 14(1) (2003) 20.Google Scholar
  16. 16.
    D. PIERCE, R. J. ASARO and A. NEEDLEMAN, Acta Metall. Mater. 31 (1983) 1951.Google Scholar
  17. 17.
    Y. HUANG, A User-Material Subroutine Incorporating Single Crystal Plasticity in the ABAQUS Finite Element Program. Harvard University Report, MECH 178 1991.Google Scholar
  18. 18.
    J. P. MCGARRY, B. P. O'DONNELL, P. E. MCHUGH and J. G. MCGARRY, Comput. Mater. Sci. 31 (2004) 421.Google Scholar
  19. 19.
    X. YOU, T. CONNOLLEY and P. E. MCHUGH, Manuscript in Preparation, 2005.Google Scholar

Copyright information

© Springer Science + Business Media, Inc. 2006

Authors and Affiliations

  • B. P. Murphy
    • 1
  • H. Cuddy
    • 1
    • 2
  • F. J. Harewood
    • 1
    • 2
  • T. Connolley
    • 1
  • P. E. McHugh
    • 1
    • 2
  1. 1.National Centre for Biomedical Engineering ScienceNational University of IrelandGalwayIreland
  2. 2.Department of Mechanical and Biomedical EngineeringNational University of IrelandGalwayIreland

Personalised recommendations