Phase fraction, texture and strain evolution in superelastic NiTi and NiTi-TiC composites investigated by neutron diffraction

R. Vaidyanathan*, M. A M Bourke, D. C. Dunand

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

106 Scopus citations

Abstract

Samples of superelastic NiTi and superelastic NiTi reinforced with 10 vol.% TiC particles were deformed under uniaxial compression to 975 MPa while neutron diffraction spectra were simultaneously collected. Despite the presence of stiff TiC particles, a macroscopic strain of 3% was obtained in the composite on loading and was fully recovered on unloading. The diffraction spectra were analyzed by Rietveld refinement that included a spherical harmonic description of the texture and a lattice plane (hkl) dependent formulation of the elastic strain. The experiments provided bulk, phase-specific measurements of the evolution of phase fractions, texture and strains during the reversible stress-induced austenite to martensite transformation responsible for the large recoverable strains. For the composite, Eshelby elastic theory is used to predict the discrete phase strains measured by neutron diffraction. The observed behavior suggests that the martensite accommodates the mismatch with the transforming austenite (while they co-exist) and the TiC particles (in the case of the composite).

Original languageEnglish (US)
Pages (from-to)3353-3366
Number of pages14
JournalActa Materialia
Volume47
Issue number12
DOIs
StatePublished - Sep 29 1999

Funding

The Manuel Lujan Jr Neutron Scattering Center is a national user facility funded by the US DOE, Office of Basic Energy Science and by Defense Programs. This work was supported in part by DOE Contract No. W-7405-ENG-36. R.V. and D.C.D. acknowledge the support of Daimler-Benz (Daimler-Chrysler) AG in the form of a research grant and R.V.'s participation in the MIT–Germany program.

ASJC Scopus subject areas

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

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