Interface selection behavior during the growth of δ-Fe grains in liquid Cu

In this study, the selection process of low-energy grain boundaries of δ-Fe grains (>25 μm) suspended in the liquid copper was studied based on the characteristics of Cu-Fe monotectic alloy which suggests that liquid Cu-rich phase and solid Fe grains can coexist over a wide temperature range. The distribution of grain boundaries was analyzed by EBSD, and it was found that Σ3 and Σ9 high angle grain boundaries with low energy were preferentially formed between δ-Fe grains at 1100 and 1150 °C. After heat treatment at 1200 °C, the δ-Fe grains agglomerated into a spherical shape with a ``bud'' structure, in which Σ1 grain boundaries dominated. Thus, the selective attachment of low-energy interfaces between floating grains in the liquid phase was elucidated. [Display omitted]