Atomistically informed phase field study of austenite grain growth

Atomistically-informed phase field simulations have been performed to investigate the effect of five common alloying elements (Nb, Ti, Mo, V, Mn) on austenite grain growth. The anisotropic simulations based on the segregation energy profiles of the solutes to four different grain boundary (GB) types from density functional theory calculations suggest a secondary role of solute drag anisotropy on grain growth. Hence, the solute trends are determined to be the same for all investigated GBs, and as a result, the $\Sigma 5(310)[001]$ GB can be considered as a representative GB for solute trend predictions. The decrease in grain growth rates due to solute additions is quantitatively described using a solute trend parameter. The following hierarchy of the solute's effectiveness to retard austenite grain growth has been determined based on the results of the presented model calculations in agreement with the experimental observations: Nb$>$Ti$>$Mo$>$V$\approx$Mn. The limitations and the strengths of the proposed approach are discussed in detail, and a potential application of this approach to steel design is proposed.