Print Email Facebook Twitter Microstructures in a carburized steel after isothermal pearlitic treatment Title Microstructures in a carburized steel after isothermal pearlitic treatment Author Abraham Mathews, J. (TU Delft Team Maria Santofimia Navarro) Farahani, H. (TU Delft Team Maria Santofimia Navarro; Tata Steel Europe Limited) Sietsma, J. (TU Delft Team Joris Dik) Petrov, R.H. (TU Delft Team Maria Santofimia Navarro; Universiteit Gent) Mecozzi, M.G. (TU Delft Team Erik Offerman) Santofimia, Maria Jesus (TU Delft Team Maria Santofimia Navarro) Date 2023 Abstract The influence of carbon concentration variations on pearlite formation (20 h at 600 °C) in a case-carburized steel is investigated. The resultant microstructure shows three distinct regions: carburized case, a transition region, and the original core. The microstructural transition from the case to the core regions is observed to be relatively sharp. The investigated region of the carburized case (0.9 wt.% C) contains two types of pearlite: ferrite + cementite and ferrite + M23C6, where the pearlitic aggregate with M23C6 shows faster formation kinetics. The kinetics of pearlite formation in the transition region (0.3 wt.% C) is very slow and is observed with only M23C6 carbide. Only around 40% austenite decomposes into pearlite in the transition region, which, in comparison to the carburized case region of 0.9 wt.% C is a fraction that is lower by a factor of two. Pearlite is absent in the investigated core region (0.16 wt.% C). The microstructure in this region is predominantly martensite and pro-eutectoid ferrite, with a fraction of ferrite well below the equilibrium fraction. Ferrite formation in this region is limited by the redistribution of mainly Ni, Mn, and Cr, and their resulting solute drag effect on the austenite/ferrite interface. A thermodynamic and kinetic argumentation of these observations is provided with the help of thermodynamic data, precipitation simulations, and a general mixed-mode Gibbs energy balance model. Subject Carburized steelKineticsMC carbidePearlite formationSolute drag To reference this document use: http://resolver.tudelft.nl/uuid:309e4bb8-c6e5-4440-8820-7c349a9555bf DOI https://doi.org/10.1016/j.jmst.2023.03.017 ISSN 1005-0302 Source Journal of Materials Science & Technology: an international journal in the field of materials science, 160, 66-75 Part of collection Institutional Repository Document type journal article Rights © 2023 J. Abraham Mathews, H. Farahani, J. Sietsma, R.H. Petrov, M.G. Mecozzi, Maria Jesus Santofimia Files PDF 1_s2.0_S1005030223003195_main.pdf 3.28 MB Close viewer /islandora/object/uuid:309e4bb8-c6e5-4440-8820-7c349a9555bf/datastream/OBJ/view