The influence of temperature on lattice parameters of coexisting phases in NiTi shape memory alloys---a neutron diffraction study

Khalil-Allafi, J.; Schmahl, W.W.; Wagner, M.; Sitepu, H.; Toebbens, D.M.; Eggeler, G.

doi:10.1016/j.msea.2003.11.062

The influence of temperature on lattice parameters of coexisting phases in NiTi shape memory alloys---a neutron diffraction study (bibtex)

by J. Khalil-Allafi, W.W. Schmahl, M. Wagner, H. Sitepu, D.M. Toebbens, G. Eggeler

Abstract:

NiTi shape memory alloys were investigated by Rietveld refinement of neutron diffraction data at various temperatures. For an aged sample of nominal composition Ni_50.7Ti_49.3 at 294 K, B2 austenite, R-phase, andNi₄Ti₃ precipitates coexist, and the Rietveld refinement provides accurate lattice parameters for the phases in this microstructure. The observed rhombohedral shape deformation occurring with the formation of Ni₄Ti₃ and R-phase in the B2 matrix is similar in magnitude and of opposite sign. Thus the strain field around a Ni₄Ti₃ precipitate can be compensated by a single variant of R-phase.

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Reference:

Khalil-Allafi, J., Schmahl, W.W., Wagner, M., Sitepu, H., Toebbens, D.M., Eggeler, G.: The influence of temperature on lattice parameters of coexisting phases in NiTi shape memory alloys---a neutron diffraction study, Materials Science and Engineering A 378, 161-164, 2004.

Bibtex Entry:

@Article{Khalil-Allafi2004a,
  author   = {Khalil-Allafi, J. and Schmahl, W.W. and Wagner, M. and Sitepu, H. and Toebbens, D.M. and Eggeler, G.},
  journal  = {Materials Science and Engineering A},
  title    = {{The influence of temperature on lattice parameters of coexisting phases in {NiTi} shape memory alloys---a neutron diffraction study}},
  year     = {2004},
  issn     = {09215093},
  number   = {1-2},
  pages    = {161--164},
  volume   = {378},
  abstract = {NiTi shape memory alloys were investigated by Rietveld refinement of neutron diffraction
data at various temperatures. For an aged sample of nominal composition
Ni\textsubscript{50.7}Ti\textsubscript{49.3} at 294 K, B2 austenite, R-phase, andNi\textsubscript{4}Ti\textsubscript{3} precipitates coexist, and the Rietveld refinement provides accurate lattice parameters for the phases in this microstructure. The observed rhombohedral shape deformation occurring with the formation of Ni\textsubscript{4}Ti\textsubscript{3} and R-phase in the B2 matrix is similar in magnitude and of opposite sign. Thus the strain field around a Ni\textsubscript{4}Ti\textsubscript{3} precipitate can be compensated by a single variant of R-phase.},
  doi      = {10.1016/j.msea.2003.11.062},
  isbn     = {4923432144},
  keywords = {Coherency strain, Lattice parameter, Ni4Ti3, NiTi shape memory alloys, Phase transformation, Rietveld method},
  url      = {http://linkinghub.elsevier.com/retrieve/pii/S0921509303015375},
}