Accuracy of composition measurement using X-ray spectroscopy in precipitate-strengthened alloys: Application to Ni-base superalloys

N. D'Souza, R. Beanland, C. Hayward, H. B. Dong

Research output: Contribution to journalArticlepeer-review

Abstract

Large scatters occur in composition measurements using wavelength-dispersive X-ray spectroscopy (WDS) when only a few precipitates are captured in the X-ray sampling volume, because the measured signal represents an averaged composition of the precipitate and the matrix phase in the sampling volume. The scatters become small when sufficient numbers of precipitates are captured and solidification segregation in the sampling volume is not significant. Monte Carlo simulations were carried out to obtain the X-ray signals from the matrix gamma and precipitated gamma' phases in as-cast Ni-base superalloys using different beam sizes for given gamma' precipitate sizes. The optimum beam size in relation to the precipitate size can be predicted for accurate composition measurements.

Original languageEnglish
Pages (from-to)1003-1013
Number of pages11
JournalActa Materialia
Volume59
Issue number3
Early online date10 Nov 2010
DOIs
Publication statusPublished - 1 Feb 2011

Keywords

  • Solidification microstructure
  • Segregation
  • Wave-length dispersive X-ray spectroscopy
  • Nickel alloys
  • Volume averaging

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