Eutectic Solidification of Ternary Al-Cu-Ag Alloys: Coupled Growth of α(Al) and AI_2Cu In Univariant Reaction

摘要

Coupled, regular eutectic growth of α(Al) and Al_2Cu from ternary Al-Cu-Ag liquid alloys is investigated with focus on the formation and the characteristics of eutectic cells in unidirectionally solidified, polycrystalline, bulk samples. The topologic anisotropy of the lamellar eutectic leads to destabilization along the lamellae with elongated cells being intermediate to stable cells, irrespective of the crystallographic orientation of the phases. The formation of stable cellular patterns with elongated or regular cell structure is explained with reference to the crystal orientation of the phases α(Al) and Al_2Cu, measured by electron backscatter diffraction (EBSD).