An Atom Probe Study of κ-carbide Precipitation in Austenitic Lightweight Steel and the Effect of Phosphorus

L. N. Bartlett*, D. C. Van Aken, J. Medvedeva, D. Isheim, N. Medvedeva, K. Song

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The influence of phosphorus on κ-carbide precipitation and alloy partitioning in an austenitic Fe-30Mn-9Al-1Si-0.9C-0.5Mo cast steel was studied utilizing a combination of transmission electron microscopy, 3D atom probe tomography, X-ray diffraction, and first-principles atomistic modeling. Increasing the amount of phosphorus from 0.006 to 0.043 wt pct P increased the kinetics of the initial ordering reaction. Specimens from the high-phosphorus steel showed some degree of short-range ordering of Fe-Al-C that took place during the quench. It was shown that phosphorus increases both the size and volume fraction of κ-carbide during aging. However, the distribution of phosphorus appears to be homogeneous, and thus long-range diffusion of phosphorus was not responsible for the observed increase in hardening. It is shown that phosphorus encourages the initial short-range ordering into the E21 structure of κ-carbide and also accelerates spinodal decomposition associated with carbon and aluminum diffusions.

Original languageEnglish (US)
Pages (from-to)5500-5515
Number of pages16
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume48
Issue number11
DOIs
StatePublished - Nov 1 2017

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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