Fatigue crack-growth in shape-memory NiTi and NiTi-TiC composites

R. Vaidyanathan, D. C. Dunand, U. Ramamurty*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

54 Scopus citations

Abstract

An experimental study was conducted to examine the room-temperature fatigue crack-growth characteristics of shape-memory NiTi matrix composites reinforced with 10 and 20 vol.% of TiC particles. Microstructural characterization of these hot-isostatically-pressed materials shows that the TiC particles do not react with the NiTi matrix and that they lack any texture. Overall fatigue crack-growth characteristics were found to be similar for the unreinforced and reinforced materials. However, a slight increase in the threshold for fatigue crack initiation was noted for the composites. The fracture toughness, as indicated by the failure stress intensity factor range, was found to be similar for all materials. Neutron diffraction studies near the crack-tip of the loaded fracture NiTi specimen detected no significant development of texture at the crack-tip. These results are explained by recourse to fractographic observations. Finally, a comparison is made between the micromechanisms of fracture of metal matrix composites, which deform by dislocation plasticity, and those of the present NiTi-TiC composites, which deform additionally by twinning. (C) 2000 Elsevier Science S.A. All rights reserved.

Original languageEnglish (US)
Pages (from-to)208-216
Number of pages9
JournalMaterials Science and Engineering A
Volume289
Issue number1-2
DOIs
StatePublished - Sep 2000

Keywords

  • Fatigue and fracture
  • Metal matrix composites
  • Micromechanisms
  • Neutron diffraction
  • Shape memory alloys

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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