Characterizing the local primary dendrite arm spacing in directionally-solidified dendritic microstructures

TL;DR

This paper introduces a Voronoi-based spatial analysis method to quantify local primary dendrite arm spacing in microstructures, aiding the understanding of process-structure-property relationships in directionally-solidified materials.

Contribution

It presents a novel Voronoi tessellation approach for analyzing dendrite spacing, comparing it with existing techniques and addressing edge effects in microstructure characterization.

Findings

Voronoi-based method effectively quantifies local dendrite spacing.

Comparison shows advantages over distance-based techniques.

Edge effects are mitigated using convex hull modifications.

Abstract

Characterizing the spacing of primary dendrite arms in directionally-solidified microstructures is an important step for developing process-structure-property relationships by enabling the quantification of (i) the influence of processing on microstructure and (ii) the influence of microstructure on properties. In this work, we utilized a new Voronoi-based approach for spatial point pattern analysis that was applied to an experimental dendritic microstructure. This technique utilizes a Voronoi tessellation of space surrounding the dendrite cores to determine nearest neighbors and the local primary dendrite arm spacing. In addition, we compared this technique to a recent distance-based technique and a modification to this using Voronoi tesselations. Moreover, a convex hull-based technique was used to include edge effects for such techniques, which can be important for thin specimens. These methods were used to quantify the distribution of local primary dendrite arm spacings, their spatial distribution, and their correlation with interdendritic eutectic particles for an experimental directionally-solidified Ni-based superalloy micrograph. This can be an important step for correlating with both processing and properties in directionally-solidified dendritic microstructures.