Details

Autor(en) / Beteiligte

• Hofer, Christina
• Bliznuk, Vitaliy
• Verdiere, An
• Petrov, Roumen
• Winkelhofer, Florian
• Clemens, Helmut
• Primig, Sophie

Titel

High-resolution characterization of the martensite-austenite constituent in a carbide-free bainitic steel

Ist Teil von

• Materials characterization, 2018-10, Vol.144, p.182-190

Ort / Verlag

United States: Elsevier Inc

Erscheinungsjahr

2018

Link zum Volltext

Quelle

Elsevier ScienceDirect Journals Complete

Beschreibungen/Notizen

• The multiphase microstructure of carbide-free bainitic steels comprises bainitic ferrite laths, retained austenite with different morphologies, a minor fraction of carbides and so-called martensite-austenite areas, which partially transform during the last cooling step. While the other constituent received much attention, little is known about the structure of the martensite-austenite constituent in carbide-free bainitic steels. Thus, in this study, it was structurally and chemically investigated by high-resolution techniques such as transmission electron microscopy and atom probe tomography after preceded unambiguous identification by electron backscatter diffraction in conventional as well as transmission mode. The results, ranging from carbon segregation to cementite precipitation in the martensitic part, indicate strong auto-tempering during final cooling which is followed by aging. Also, some kind of structural modulation in the austenite belonging to the martensite-austenite areas was observed. Atom probe tomography revealed a heterogeneous carbon distribution, further supporting the findings by transmission electron microscopy. •Microstructural characterization of martensite-austenite (M-A) areas by TKD and TEM•Auto-tempering effects ranging from C clustering to carbide formation in martensite•Signs of structural modulation of austenite in M-A areas by electron diffraction•Heterogeneous C distribution within M-A areas due to auto-tempering during cooling