Determining Alloy Nucleation Core Origin and Grain Refinement Strategy Based on the Dependence Degree of Content Difference

What is nucleation core origin during alloy solidification, especially for equiaxed grains? Different dependence degrees of the magnitude or occurrence element content variation could shed light on this long-standing issue in actual large ingots. Here, based etched surface height and grayscale, distributions within solid fraction continuous casting billets additive manufacturing samples are first obtained by only a two-dimensional surface. Then, combined with phylogenetic trees, rank correlation applied to measure differences initial solidification. Assessments external helpful determine low internal degree facilitates grain refinement. Moreover, casting, some cores central zone confirmed originate from edge-chilled high area ratio under superheat, which attributed temperature gradient growth rate rather than remelting fewer originating chilled zone. In addition, floating behavior separated grains can be affected gravity force, but these should more active when increasing superheat that may weaken influence certain extent.