Growth of Self Organized Eutectic Fibers from LiF-Rare Earth Fluoride Systems

TL;DR

This study demonstrates the growth of self-organized eutectic fibers in LiF-Rare Earth Fluoride systems using the micro-pulling-down method, revealing how growth rate influences microstructure and differences between compositions.

Contribution

It introduces a method to grow eutectic fibers with controlled microstructure in LiF-Rare Earth Fluoride systems at high pulling rates.

Findings

Eutectic fibers can be grown at pulling rates over 120 mm/h.

Fibril spacing can be reduced to 1 micrometer at 300 mm/h.

LiF-LiYF4 forms facetted colonies more readily than LiF-LiGdF4.

Abstract

Eutectic fibers consisting of an ordered arrangement of LiF fibrils inside a LiREF4 matrix (RE = Y, Gd) can be grown with the micro-pulling-down method at sufficiently large pulling rate exceeding 120 mm/h. The distance between individual fibrils could be scaled down to 1 micrometer at 300 mm/h pulling. LiF-LiYF4 has stronger tendency to form facetted eutectic colonies than LiF-LiGdF4, explained by the larger entropy of melting of the former.