title: Combined nano-SIMS/AFM/EBSD analysis and atom probe tomography, of carbon distribution in austenite/ε-martensite high-Mn steels.
abstract: We introduce a new experimental approach for the identification of the atomistic position of interstitial carbon in a high-Mn binary alloy consisting of austenite and ε-martensite. Using combined nano-beam secondary ion mass spectroscopy, atomic force microscopy and electron backscatter diffraction analyses, we clearly observe carbon partitioning to austenite. Nano-beam secondary ion mass spectroscopy and atom probe tomography studies also reveal carbon trapping at crystal imperfections as identified by transmission electron microscopy. Three main trapping sites can be distinguished: phase boundaries between austenite and ε-martensite, stacking faults in austenite, and prior austenite grain boundaries. Our findings suggest that segregation and/or partitioning of carbon can contribute to the austenite-to-martensite transformation of the investigated alloy.
authors.affiliation: Max-Planck-Insititut für Eisenforschung, Max-Planck-Strasse 1, 40237 Düsseldorf, Germany; Department of Materials Science and Engineering, POSTECH, Pohang 790-784, Republic of Korea.
authors.forename: Jae-Bok
authors.initials: JB
authors.lastname: Seol
authors.forename: B-H
authors.initials: BH
authors.lastname: Lee
authors.forename: P
authors.initials: P
authors.lastname: Choi
authors.forename: S-G
authors.initials: SG
authors.lastname: Lee
authors.forename: C-G
authors.initials: CG
authors.lastname: Park
keywords: Atom probe tomography; Carbon in high-Mn steel; Electron back scattered diffraction; Nano-beam secondary ion mass spectroscopy; Transmission electron microscopy; ε-martensite