Analysis of precipitation mechanisms in tempering of low-alloy steels using the kinetic theory of the overlapping transformations

Comments About the Strengthening Mechanisms in Commercial Microalloyed Steels and Reaction Kinetics on Tempering in Low-Alloy Steels

“…According to reasoning followed in [33], for times t' end1 <t'<t' end2 , the second process develops alone in this time interval, therefore ξ 2 '(t') increases while ξ''(t') decreases (for the case where l >0 …”

“…Our approach focusses on the behavior of the function Z(ξ) vs. ξ [33,43]. This function is not symmetrical with reference to its maximum at ξ=0.632.…”

“…Let us consider two processes that proceed in the same sense during the isothermal treatment ( p >0) [33]. Thus, it is necessary to begin the study not from the origin of the data obtained from the measuring equipment but from the moment of time when the isothermal regime is reached.…”

“…Work interval in ' 2 (t') from the final Table 10.a Kinetic parameters for the second precipitation process according to the KTOPT, [33].…”

“…Another situation that commonly occurs when fitting the models, such as Johnson-Mehl-Avrami-Kolmogorov (JMAK)-like models, to the entire curve of the fraction transformed (ξ(t)) vs. lnt, is to discard the experimental uncertainties in the determination of the fraction transformed [31,32]. Fitting such models to the entire experimental curve of the fraction transformed could therefore, in certain circumstances result in the prediction of unrealistic kinetic parameters [33].…”