Kinetic Description of (Cr, Fe)₇C₃ Carbide Precipitation from Austenite in High-Carbon Fe-Cr-C Ternary Alloys

Abstract:

The paper develops a model of precipitation of secondary (Cr, Fe)₇C₃ carbides from austenite in high-carbon chromium white cast irons of the ternary system Fe–Cr–C. Description of isothermal kinetics is based on traditional approaches to diffusionally controlled growth of particles, and approximation of the shape of isothermal TTT curve by a parabola permitted to apply the Scheil–Steinberg integral for transition to continuous cooling conditions. Model parameters were determined from literature experimental data on the change of M_s temperature after continuous cooling with different rates. Dependences of these parameters on alloy composition were then also defined. Results of the work, combined with the previously proposed model of carbide dissolution in the gamma phase during austenitization, permit to calculate isothermal (TTT) and continuous cooling (CCT) precipitation curves for an arbitrary ternary Fe–Cr–C alloy after given austenitization mode.

• Periodical: Solid State Phenomena (Volume 265)
• Pages: 1005-1010
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.265.1005
• Online since: September 2017
• Authors: E.S. Vasyukova, K.Yu. Okishev*, A.S. Sozykina, A.M. Karlikov, D.A. Mirzaev
• Keywords: Austenite, Chromium Cast Irons, Kinetics, Martensitic Point, Precipitation, Secondary Carbides

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