High strength, low stiffness, porous NiTi with superelastic properties

Christian Greiner, Scott M. Oppenheimer, David C. Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticle

177 Scopus citations

Abstract

Near-stoichiometric NiTi with up to 18% closed porosity was produced by expansion at 1200 °C of argon-filled pores trapped by powder metallurgy within a NiTi billet. When optimally heat-treated, NiTi with 6-16% porosity exhibits superelasticity, with recoverable compressive strains up to 6% at a maximum compressive stress up to 1700 MPa. The apparent Young's modulus of NiTi with 16% porosity, measured during uniaxial compression, is in the range of 15-25 GPa (similar to human bone), but is much lower than measured ultrasonically (∼40 GPa), or predicted from continuum elastic mechanics. This effect is attributed to the reversible stress-induced transformation contributing to the linear elastic deformation of porous NiTi. The unique combination of low stiffness, high strength, high recoverable strains and large energy absorption of porous superelastic NiTi, together with the known biocompatibility of NiTi, makes this material attractive for bone-implant applications.

Original languageEnglish (US)
Pages (from-to)705-716
Number of pages12
JournalActa Biomaterialia
Volume1
Issue number6
DOIs
StatePublished - Nov 1 2005

Keywords

  • Bone replacement
  • Foams
  • Nickel
  • Nitinol
  • Superelasticity
  • Titanium

ASJC Scopus subject areas

  • Biotechnology
  • Biomaterials
  • Biochemistry
  • Biomedical Engineering
  • Molecular Biology

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