Columnar-to-equiaxed transition and grain refinement by solute interaction effects

Abstract

The effects of single solute on grain refinement of binary alloys during casting have been revealed with supercooling parameter (P) and growth restriction factor (Q) theory in the literature. However, multiple-solute effects are still not clear due to the interaction between different solutes. In this work, we proposed a method to make remarkable grain refinement effects with minor Ti and C solutes. In addition, a novel method for columnar-to-equiaxed transition and grain refinement was also put forward based on solute interaction effects between multiple solute elements. Two solutes were designed first by considering (a) both segregated in solid-liquid interfaces with partition coefficients <1 and (b) with properly strong interaction energy. The interaction effect between the solutes enhances build-ups ahead of the solid-liquid interface and generate stronger constitutional supercooling, which leads to significant grain refinement in the selected model metals of Ni and Fe.