Microstructural Characterization of Lamellar Features in TiAl by FIB Imaging

Peter, D.; Eggeler, G.; Wagner, M.F.-X.

doi:10.1002/adem.200900339

Microstructural Characterization of Lamellar Features in TiAl by FIB Imaging (bibtex)

by D. Peter, G. Eggeler, M.F.-X. Wagner

Abstract:

A novel experimental procedure is introduced to determine phase fractions and the distribution of individual phases of TiAl-based two-phase alloys using the focused ion beam (FIB) technique. Two γ-titanium aluminide alloys with a fine-grained duplex and a nearly lamellar microstructure are examined. The special FIB-based preparation procedure results in high contrast ion beam-induced images for all investigated alloys and allows to quantify the phase contents easily by automated microstructural analysis. Fine two-phase structures, e.g. lamellar colonies in γ-TiAl, can be imaged in high resolution with respect to different phases. To validate the FIB-derived data, we compare them to results obtained with another method to determine phase fractions, electron back-scatter diffraction (EBSD). This direct comparison shows that the FIB-based technique generally provides slightly higher a₂-fractions, and thus helps to overcome the limited lateral resolution near grain boundaries and interfaces associated with the conventional EBSD approach. Our study demonstrates that the FIB-based technique is a simple, fast, and more exact way to determine high resolution microstructural characteristics with respect to different phase constitutions in two-phase TiAl alloys and other such materials with fine, lamellar microstructures.

Reference:

Peter, D., Eggeler, G. and Wagner, M.F.-X.: Microstructural Characterization of Lamellar Features in TiAl by FIB Imaging, Advanced Engineering Materials 12, 447-452, 2010.

Bibtex Entry:

@Article{Peter2010,
  Title                    = {{Microstructural Characterization of Lamellar Features in {TiAl} by {FIB} Imaging}},
  Author                   = {Peter, D. and Eggeler, G. and Wagner, M.F.-X.},
  Journal                  = {Advanced Engineering Materials},
  Year                     = {2010},
  Number                   = {6},
  Pages                    = {447--452},
  Volume                   = {12},

  Abstract                 = {A novel experimental procedure is introduced to determine phase fractions and the distribution of individual phases of TiAl-based two-phase alloys using the focused ion beam (FIB) technique. Two γ-titanium aluminide alloys with a fine-grained duplex and a nearly lamellar microstructure are examined. The special FIB-based preparation procedure results in high contrast ion beam-induced images for all investigated alloys and allows to quantify the phase contents easily by automated microstructural analysis. Fine two-phase structures, e.g. lamellar colonies in γ-TiAl, can be imaged in high resolution with respect to different phases. To validate the FIB-derived data, we compare them to results obtained with another method to determine phase fractions, electron back-scatter diffraction (EBSD). This direct comparison shows that the FIB-based technique generally provides slightly higher a\textsubscript{2}-fractions, and thus helps to overcome the limited lateral resolution near grain boundaries and interfaces associated with the conventional EBSD approach. Our study demonstrates that the FIB-based technique is a simple, fast, and more exact way to determine high resolution microstructural characteristics with respect to different phase constitutions in two-phase TiAl alloys and other such materials with fine, lamellar microstructures.},
  Doi                      = {10.1002/adem.200900339},
  ISBN                     = {1527-2648},
  ISSN                     = {14381656}
}