| Abstract Scope |
We investigate the solidification of an irregular eutectic, in which one of the solid phases grows faceted from the liquid. There exist conflicting accounts in the literature on the degree of coupling between the solid phases at the growth front. Here, we obtain nanoscopic and 3D insights enabled by new developments in synchrotron-based x-ray nanotomography by transmission x-ray microscopy (TXM). We study via TXM the Al-Al3Ni eutectic as a model system. At low velocity (V) in directional solidification, we observe both coupling and decoupling of the two solid phases. At higher V, the lead distance of the faceted Al3Ni phase is reduced or even eliminated, and its shape ceases to be governed by faceted growth in a liquid. We observe a faceted to rod-like transition upon increasing V. In this talk, we will discuss the interrelationships between coupling, velocity, composition, and interfacial morphology of broad relevance to irregular eutectic alloys. |