Quantitative modeling and experimental verification of carbide precipitation in a martensitic Fe-0.16 wt%C-4.0 wt%Cr alloy
2016 (English)In: Calphad, ISSN 0364-5916, E-ISSN 1873-2984, Vol. 53, 39-48 p.Article in journal (Refereed) PublishedText
Precipitation of carbides during tempering of a martensitic Fe-0.16 wt% C-4.0 wt% Cr alloy has been investigated by experimental analysis and quantitative modeling. It is found that both M7C3 and M23C6 form, at low- and high-angle grain boundaries in the martensite, as well as, at dislocations inside individual laths of martensite, during tempering at 700 °C. The applied Kampmann-Wagner numerical (KWN) modeling, utilizing CALPHAD thermodynamic and kinetic databases together with an assumption of local equilibrium and a constant tie-line, captures the main features of the precipitation, with a transient formation of metastable M23C6, and with M7C3 as the stable carbide. The predicted volume fraction and size are in reasonable agreement with extraction experiments for M7C3. However, for the metastable minority carbide M23C6, the modeling underestimates the size and overestimates the volume fraction within the transient time. With sound thermodynamic databases and physical parameter input, the adopted simplified modeling scheme is a valuable tool for materials design and optimization. Furthermore, by treating conditions at the phase interface more rigorously it is possible to account for different mechanisms of precipitation, such as e.g., non-partitioning local equilibrium, which could be important in systems where interstitial elements diffuse much faster than the substitutional ones.
Place, publisher, year, edition, pages
Elsevier, 2016. Vol. 53, 39-48 p.
Electron microscopy, Microstructure, Modeling, Precipitation, Steels, Tempering, Carbides, Chromium alloys, Grain boundaries, Martensite, Models, Phase interfaces, Steel, Volume fraction, Carbide precipitation, Different mechanisms, Experimental analysis, Experimental verification, High angle grain boundaries, Interstitial elements, Quantitative modeling, Thermodynamic database, Precipitation (chemical)
IdentifiersURN: urn:nbn:se:kth:diva-186937DOI: 10.1016/j.calphad.2016.03.001ISI: 000377315100005ScopusID: 2-s2.0-84960155147OAI: oai:DiVA.org:kth-186937DiVA: diva2:929367
Funding Details: U1260204, NSFC, National Natural Science Foundation of China
QC 201605182016-05-182016-05-162016-07-05Bibliographically approved