Mechanical anisotropy of shape-memory NiTi with two-dimensional networks of micro-channels

Anselm J. Neurohr, David C. Dunand

Research output: Contribution to journalArticlepeer-review

23 Scopus citations

Abstract

Ni-51.4 at.% Ti (Nitinol) containing 24 and 34 vol.% orthogonally interweaving micro-channels with 350-400 μm diameters was fabricated by a powder-metallurgy method. NiTi powder preforms containing steel wire meshes arranged in parallel layers were hot-pressed into NiTi/steel composites, from which the meshes were removed electrochemically, thereby producing micro-channels with tailorable morphology, fraction, and orientation. The compressive stiffness (15-35 GPa) and strength (420-780 MPa) can be controlled by the volume fraction and orientation of the micro-channels. Stiffness values are compared against analytical foam and composite models. A combination of elasticity, superelasticity, and the shape-memory effect allows for high strain recovery (93-95% of an applied compressive strain of 5%).

Original languageEnglish (US)
Pages (from-to)4616-4630
Number of pages15
JournalActa Materialia
Volume59
Issue number11
DOIs
StatePublished - Jun 2011

Keywords

  • Nickel titanium
  • Nitinol
  • Porous material
  • Shape memory
  • Space-holder

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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