Voltage-pulsed and laser-pulsed atom probe tomography of a multiphase high-strength low-carbon steel

Michael D. Mulholland, David N Seidman*

*Corresponding author for this work

Research output: Contribution to journalArticle

20 Scopus citations

Abstract

The differences in artifacts associated with voltage-pulsed and laser-pulsed (wavelength = 532 or 355 nm) atom-probe tomographic (APT) analyses of nanoscale precipitation in a high-strength low-carbon steel are assessed using a local-electrode atom-probe tomograph. It is found that the interfacial width of nanoscale Cu precipitates increases with increasing specimen apex temperatures induced by higher laser pulse energies (0.6-2 nJ pulse -1 at a wavelength of 532 nm). This effect is probably due to surface diffusion of Cu atoms. Increasing the specimen apex temperature by using pulse energies up to 2 nJ pulse -1 at a wavelength of 532 nm is also found to increase the severity of the local magnification effect for nanoscale M2C metal carbide precipitates, which is indicated by a decrease of the local atomic density inside the carbides from 68 ± 6 nm -3 (voltage pulsing) to as small as 3.5 ± 0.8 nm -3. Methods are proposed to solve these problems based on comparisons with the results obtained from voltage-pulsed APT experiments. Essentially, application of the Cu precipitate compositions and local atomic density of M 2C metal carbide precipitates measured by voltage-pulsed APT to 532 or 355 nm wavelength laser-pulsed data permits correct quantification of precipitation.

Original languageEnglish (US)
Pages (from-to)950-962
Number of pages13
JournalMicroscopy and Microanalysis
Volume17
Issue number6
DOIs
StatePublished - Dec 1 2011

Keywords

  • Cu precipitation
  • M C carbides
  • atom probe tomography
  • precipitate analysis

ASJC Scopus subject areas

  • Instrumentation

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