DGIST Scholar: Atomistic investigations of kappa-carbide precipitation in austenitic Fe-Mn-Al-C lightweight steels and the effect of Mo addition

Center for Core Research Facilities 1. Journal Articles

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Atomistic investigations of kappa-carbide precipitation in austenitic Fe-Mn-Al-C lightweight steels and the effect of Mo addition

Title: Atomistic investigations of kappa-carbide precipitation in austenitic Fe-Mn-Al-C lightweight steels and the effect of Mo addition

Author(s): Moon, Joonoh ; Park, Seong-Jun ; Jang, Jae Hoon ; Lee, Tae-Ho ; Lee, Chang-Hoon ; Hong, Hyun-Uk ; Suh, Dong-Woo ; Kim, Seong Hoon ; Han, Heung Nam ; Lee, Bong Ho

Author Keywords: Lightweight steel ; kappa-Carbide precipitation ; Atom probe tomography (APT) ; First-principles calculations ; Nanoindentation

Keywords: ALLOYS ; Aluminum ; Atom-Probe Tomography ; Atom Probe Tomography (APT) ; AUSTENITE ; Calculations ; Carbide Precipitation ; Carbides ; Energy Contribution ; First-Principles Calculation ; First-Principles Calculations ; Formation Energies ; High Resolution Transmission Electron Microscopy ; Kappa-Carbide Precipitation ; Light-Weight Steels ; Lightweight Steel ; Manganese ; Nanoindentation ; Nanoindentation Experiments ; Precipitation Behavior ; Probes ; Strain Energy ; Transmission Electron Microscopy

Abstract: The effect of Mo addition on precipitation behavior of κ-(Fe,Mn)3AlC during aging in austenitic Fe-Mn-Al-C lightweight steels was investigated. First-principles calculations indicate that substitution of Fe or Mn by Mo in κ-carbide is energetically unfavorable in the respect to formation energy, and it, moreover, increases strain energy contribution to interfacial energy between austenite matrix and κ-carbide. Atom probe tomography (APT) and transmission electron microscopy (TEM) analysis showed the results consistent with the calculations, i.e., Mo didn't partition into κ-carbide and delayed κ-carbide precipitation. Finally, nanoindentation experiments presented that Mo addition changed the aging hardening behavior, corresponding to κ-carbide precipitation behavior. © 2016 Acta Materialia Inc.