Effects of Mn partitioning on nanoscale precipitation and mechanical properties of ferritic steels strengthened by NiAl nanoparticles

Zengbao Jiao, J. H. Luan, M. K. Miller, C. Y. Yu, C. T. Liu

Research output: Journal article publicationJournal articleAcademic researchpeer-review

62 Citations (Scopus)

Abstract

The critical role of Mn partitioning in the formation of ordered NiAl nanoparticles in ferritic steels has been examined through a combination of atom probe tomography (APT) and thermodynamic and first-principles calculations. Our APT study reveals that Mn partitions to the NiAl nanoparticles, and dramatically increases the particle number density by more than an order of magnitude, leading to a threefold enhancement in strengthening. Atomistic structural analyses reveal that Mn is energetically favored to partition to the NiAl nanoparticles by preferentially occupying the Al sublattice, which not only increases the driving force, but also reduces the strain energy for nucleation, thereby significantly decreasing the critical energy for formation of the NiAl nanoparticles in ferritic steels. In addition, the effects of Mn on the precipitation strengthening mechanisms were quantitatively evaluated in terms of chemical strengthening, coherency strengthening, modulus strengthening and order strengthening.
Original languageEnglish
Pages (from-to)283-291
Number of pages9
JournalActa Materialia
Volume84
DOIs
Publication statusPublished - 1 Feb 2015
Externally publishedYes

Keywords

  • Atom probe tomography
  • Mechanical property
  • Microsegregation
  • NiAl nanoparticle
  • Precipitation

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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