Three-dimensional morphology of an ultrafine Al-Si eutectic produced via laser rapid solidification

TL;DR

This study uses advanced 3D imaging and analysis to reveal fundamental differences in the microstructure of ultrafine Al-Si eutectic alloys produced by laser rapid solidification, challenging previous assumptions about their similarity to impurity-doped alloys.

Contribution

It introduces a high-throughput, quantitative method for analyzing 3D eutectic microstructures, distinguishing their origins based on branching behavior.

Findings

Ultrafine eutectic microstructures differ fundamentally from impurity-modified ones.

The analysis reveals distinct branching statistics indicating different microstructural origins.

The method can be applied to other volumetric datasets for microstructural characterization.

Abstract

Al-Si alloys processed by laser rapid solidification yield eutectic microstructures with ultrafine and interconnected fibers. Such fibrous structures have long been thought to bear resemblance to those formed in impurity-doped alloys upon conventional casting. Here, we show that any similarity is purely superficial. By harnessing high-throughput characterization and computer vision techniques, we perform a three-dimensional analysis of the branching behavior of the ultrafine eutectic and compare it against an impurity-modified eutectic as well as a random fractal (as a benchmark). Differences in the branching statistics point to different microstructural origins of the impurity- and quench-modified eutectic. Our quantitative approach is not limited to the data presented here but can be used to extract abstract information from other volumetric datasets, without customization.