Correspondence lattice rotations in eutectic crystals

Abstract

A simple interference technique shows that in sub-grains of the Al-CuAl₂ eutectic alloy the lamellae are inclined in a fan-like arrangement having a pitch of 10’ to 20’ per lamella. This structure automatically produces variations in lamellar spacing at the growth front and can also give rise to apparently spiral growth in directionally frozen eutectic specimens. Some correlations with asymmetric phase and interfacial orientations are noted.