Indentation Response and Structure-Property Correlation in a Bimodal Ti–6Al–4V Alloy

Sen, I.; Roy, S.; Wagner, M.F.-X.

doi:10.1002/adem.201700298

Indentation Response and Structure-Property Correlation in a Bimodal Ti–6Al–4V Alloy (bibtex)

by I. Sen, S. Roy, M.F.-X. Wagner

Abstract:

Understanding the deformation behavior of multi-phase alloys under external loading requires careful mechanical characterization of the individual constituent phases at various length scales. The present study first evaluates the elastic moduli and hardness of the microstructural constituents viz. primary α (αp) and transformed β (secondary α (αs) plus retained prior β) phases in a bimodal Ti–6Al–4V alloy by nano-indentation using different loads. The bulk mechanical properties of the overall microstructure are then determined by grid wise nano-indentation, as well as micro-indentation. The alloy shows a pronounced indentation size effect; the hardness increases with the decrease in indentation load, or depth of penetration. Assuming an iso-stress condition for individual constituents (αp and transformed β) in the rule of mixture approach, the bulk mechanical properties of the Ti–6Al–4V alloy are reasonably predicted. Such prediction of bulk properties, however, is not possible when a similar calculation is performed using iso-strain condition. The transformed β phase shows disparity between the estimated and experimental values, while considering the αs and β phases individually, on both iso-stress and iso-strain assumptions. From these results, the influence of individual microstructural phases (size, distribution, volume fraction, morphology) and the interfaces between them, is found key in controlling the overall bulk mechanical response of the alloy system.

Reference:

Sen, I., Roy, S. and Wagner, M.F.-X.: Indentation Response and Structure-Property Correlation in a Bimodal Ti–6Al–4V Alloy, Advanced Engineering Materials 19, 1700298, 2017.

Bibtex Entry:

@Article{Sen2017,
  author   = {Sen, I. and Roy, S. and Wagner, M.F.-X.},
  title    = {Indentation Response and Structure-Property Correlation in a Bimodal Ti–6Al–4V Alloy},
  journal  = {Advanced Engineering Materials},
  year     = {2017},
  volume   = {19},
  number   = {12},
  pages    = {1700298},
  month    = dec,
  issn     = {1527-2648},
  note     = {1700298},
  abstract = {Understanding the deformation behavior of multi-phase alloys under external loading requires careful mechanical characterization of the individual constituent phases at various length scales. The present study first evaluates the elastic moduli and hardness of the microstructural constituents viz. primary α (αp) and transformed β (secondary α (αs) plus retained prior β) phases in a bimodal Ti–6Al–4V alloy by nano-indentation using different loads. The bulk mechanical properties of the overall microstructure are then determined by grid wise nano-indentation, as well as micro-indentation. The alloy shows a pronounced indentation size effect; the hardness increases with the decrease in indentation load, or depth of penetration. Assuming an iso-stress condition for individual constituents (αp and transformed β) in the rule of mixture approach, the bulk mechanical properties of the Ti–6Al–4V alloy are reasonably predicted. Such prediction of bulk properties, however, is not possible when a similar calculation is performed using iso-strain condition. The transformed β phase shows disparity between the estimated and experimental values, while considering the αs and β phases individually, on both iso-stress and iso-strain assumptions. From these results, the influence of individual microstructural phases (size, distribution, volume fraction, morphology) and the interfaces between them, is found key in controlling the overall bulk mechanical response of the alloy system.},
  doi      = {10.1002/adem.201700298},
  keywords = {Nano and micro-indentation, bimodal Ti–6Al–4V, indentation size effect, rule of mixture, iso-stress and iso-strain, grain boundary and interface},
}