Predicting microstructure and microsegregation in multicomponent alloys

Abstract

OverviewAccurate predictions of microstructure and microsegregation in metallic alloys are highly important for applications such as process optimization and alloy development. This article gives an overview of the methods developed during the past 30 years for solidification simulation on a microscopic scale, with a special emphasis on multicomponent alloys. Analytical approaches as well as advanced numerical models coupled with greatly simplified phase diagrams and thermodynamically calculated phase diagrams have been critically reviewed. Factors that influence the predictions, such as solid-state diffusion, coarsening of dendrite arms, undercooling effects, and, most importantly, the accuracy of the phase diagram are discussed, and suggestions for further research are given.

Modeling Inclusion Formation during Solidification of Steel: A Review

“…Kraft and Chang [13] summarized a variety of modeling work on microsegregation despite ongoing development. The existing modeling approaches consist of numerical and analytical solutions.…”

“…The Gibbs free energy change is the most popular thermodynamic criteria. At a given temperature, the Gibbs energy change (∆G) for the reaction is given by Equation (13).…”

Macrosegregation in Steel Ingots: The Applicability of Modelling and Characterisation Techniques

“…More recently the use of thermodynamic databases in steel microsegregation models has become popular [153][154][155][156] and kinetic effects have also been incorporated into models .111,157-163) Nevertheless, adding such complexity into macrosegregation models often comes at great computational expense, and consequently there has been some development of rapid microsegregation models for incorporation into macromodels. 164) For those seeking further details on microsegregation models, the review by Kraft and Chang 165) is a useful starting point.…”

Numerical Models of Crystallization and Its Direction for Metal and Ceramic Materials in Technical Application

“…The main limiting factor of all existing mathematical micro-segregation models consists in lack of available thermodynamic and kinetic data, especially for systems of higher orders. There is also little experimental data to check the models (Kraft & Chang, 1997).…”

“…Nevertheless, there is a strong industrial need to investigate and simulate more complex alloys because nearly all current commercial alloys have many components often exceeding ten elements. Moreover, computer simulation have shown that even minute amounts of alloying elements can significantly influence microstructure and micro-segregation and cannot be neglected (Kraft & Chang, 1997). Dendritic crystallisation is general form of crystallisation of salts, metals and alloys.…”