Sensivity Analysis of the Cellular Automata Model for Austenite-Ferrite Phase Transformation in Steels

Abstract

The main goal of the present research is to realize a sensitivity analysis of the developed complex micro scale austenite (γ) to ferrite (α) phase transformation model. The proposed solution is implemented in the developed Cellular Automata Framework that facilitates implementation of various microstructure evolution models. Investigated model predicts phase transformation progress starting from the fully austenitic or two-phase regions. Theoretical background of the implemented austenite-ferrite phase transformation model is presented in the paper. The defined transition rules for initiation and subsequent growth as well as internal variables for each particular CA cell are also discussed. Examples of results obtained from the developed model, as well as model capabilities are shown. Finally sensitivity analysis using Morris OAT Design is also presented and discussed.

A review on the modeling and simulations of solid-state diffusional phase transformations in metals and alloys

“…The cellular automaton will be in progress by synchronously updating these state variables for all lattice cells in each time step, and thus spatial and temporal microstructure evolution is described. In recently, many cellular automaton models for solid-state diffusional phase transformation have been developed to focus on simulating the austenite-ferrite phase transformations in Fe-C alloy in which interstitial solute carbon atoms have high diffusion coefficient [139][140][141]. However, as regard to substitution solid solution like Fe-Mn or Ti-Al-Mo alloy, the attractive force occurs from the solute atoms on the moving interface, which is so-called solute drag without existing in interstitial solid solution.…”

Cellular automata simulation for high temperature austenite grain growth based on thermal activation theory and curvature-driven mechanism

“…Moreover, CA method has been used in the simulation of austenite growing and transformation to ferrite. Golab R and Bachniak D have realized a sensitivity analysis of the developed complex micro scale austenite to ferrite phase transformation model based on CA [8]. In An D's paper, the preferential nucleation sites of austenite, the driving force of phase transformation coupled with thermodynamic parameters, solute partition at the ferrite/austenite interface, and carbon diffusion in both the ferrite and austenite phases are taken into consideration [9].…”

Cellular Automata Finite Element Approach for Modelling Microstructure Evolution under Thermo-Mechanical Processing Conditions

“…These internal variables are used in the transition rules to replicate mechanisms of phase transformation. Details on this approach can be found in [15]. Two major parts of the model are defined to describe nucleation and growth of the ferrite grains in the austenitic matrix.…”

“…The transition rules describing growth of ferrite grains during phase transformation are designed to replicate experimental ob-servations of mechanisms responsible for this process [15]. The velocity of the α/γ interface is assumed to be a product of the mobility M and the driving force for interface migration F:…”