An Alternative to Avrami Equation

Abstract

This paper proposes an alternative to the Avrami equation capable of describing whole transformation curves with significant fitting-correlations. The model bears physically meaningful parameters which permit considering the initial transformation kinetics independently from the subsequent microstructural evolution. Data of martensite, bainite, recrystallization, and pearlite transformations validate the model. Further to the expeditious description of transformation curves, the model guides the modeling of specific mechanisms.

Martensite’s Logistic Paradigm

“…Throughout the text, one discusses the meaning of these parameters. This equation showed excellent agreement when fitted to transformations ranging from martensite to pearlite 10,11 . *e-mail: andrealves@metalmat.ufrj.br However, another way to approach formal kinetics is possible.…”

“…Focusing the transformations in steels, the present authors have proposed an alternative to Avrami's equation [9][10][11]…”

“…In the equation above, x is an "advance" variable, which in previous works [9][10][11] was equal to temperature, magnetic field, mechanical deformation, and time. The x i is the first datum in a dataset.…”

Synthesis and characterization of sodium hafnium oxide (Na2HfO3) and its high-temperature CO2 sorption properties

“…These kinetic models were chosen as they are based on a chemisorption process. The non-linear and linear versions of these kinetic models can be summarized with the following equations: 55–57 Pseudo-first order non-linear: q t = q e (1 − e k 1 t )Avrami non-linear: ln[ln( q e / q e − q t )] = n ln k + n ln t Linear: V v = 1 − exp(− kt n )Avrami–Erofeev non-linear: ln[−ln 1 − α )] = ln k + n ln t …”

“…These kinetic models were chosen as they are based on a chemisorption process. The non-linear and linear versions of these kinetic models can be summarized with the following equations: [55][56][57] Pseudo-first order non-linear: q t =q e (1 − e k1t )…”