Three-dimensional (3-D) atom probe tomography of a Cu-precipitation- strengthened, ultrahigh-strength carburized steel

Benjamin L. Tiemens*, Anil K. Sachdev, Raja K. Mishra, Gregory B. Olson

*Corresponding author for this work

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

In an effort to reduce material cost, experimental steel alloys were developed that incorporated Cu precipitation in lieu of costly Co alloying additions in secondary hardening carburizing gear steels. This work utilizes three-dimensional atom probe tomography to study one of these prototype alloys and quantify the nanoscale dispersions of body-centered cubic (bcc) Cu and M 2C alloy carbides used to strengthen these steels. The temporal evolution of precipitate, size, morphology, and interprecipitate interactions were studied for various tempering times. Findings suggest that Cu precipitation does act as a catalyst for heterogeneous nucleation of M 2C carbides at relatively high hardness levels; however, the resultant volume fraction of strengthening carbides was noticeably less than that predicted by thermodynamic equilibrium calculations, indicating a reduced potency compared with Co-assisted precipitation. Microstructural information such as precipitate size and volume fraction was measured at the peak hardness condition and successfully used to recalibrate alloy design models for subsequent alloy design iterations.

Original languageEnglish (US)
Pages (from-to)3626-3635
Number of pages10
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume43
Issue number10
DOIs
StatePublished - Oct 1 2012

ASJC Scopus subject areas

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

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