Analytical Description of the Bainite Transformation Kinetics in Steels 300M and D6AC

Abstract:

The most widely used equation for analytical description of the transformation kinetics of the metastable solid solutions (the steel austenite in particular) is Kolmogorov-Johnson-Mehl-Avrami (KJMA) equation [1]. However the practical analysis of the experimental isothermal bainite transformation kinetics often gives significant deviation from the conventional theory [2]. This problem can be solved by the derivation of an analytical function which would provide the best fit of the experimental results. Two analytical approaches describing the kinetics of bainite transformation in steels 300M and D6AC are proposed. The first one is based on an approximation of the experimental ln (-ln (1-Р)) vs. ln τ dependence by a second order polynomial function. The second approach is based on the solution of the differential equation y(x) = ay’(x)+b, where x= ln τ, y(x) = ln(-ln(1-P)). A comparison between the proposed approaches and Kolmogorov - Johnson - Mehl – Avrami equation is conducted. The adequacy of the two analytical models is estimated using Fisher ratio test.

• Periodical: Materials Science Forum (Volume 907)
• Pages: 31-37
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.907.31
• Online since: September 2017
• Authors: Aleksandra A. Kuklina, Mikhail V. Maisuradze, Yury V. Yudin
• Keywords: 300M, Bainite, D6AC, Kinetics, Kolmogorov-Johnson-Mehl-Avrami Equation, Steel

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