The size effect on nucleation process during solidification of metals

TL;DR

This paper explores how the size and shape of metal samples influence crystal nucleation during solidification, revealing different dominant factors in flat versus bulk samples.

Contribution

It provides new insights into the size-dependent mechanisms of nucleation in metals, considering both flat and bulk geometries.

Findings

Nucleation rate in flat samples is mainly affected by mold wall activity.

In bulk samples, supercooling and impurities significantly influence nucleation.

Different factors dominate nucleation depending on sample geometry.

Abstract

This work investigates the mechanisms of crystal nucleation in metal melts, in dependence on the influence of their shape and volume. Investigations were conducted on both thin flat and bulk samples prepared of low-temperature Wood's metal alloy and transparent organic media (camphene and diphenylamine). The study revealed that in flat samples, the nucleation rate is primarily influenced by the activity of the mold wall surface, which is affected by melt overheating and subcooling, while in bulk samples, supercooling and nucleation are additionally influenced by factors such as impurity activity, temperature, and density fluctuations.