RT Journal Article SR Electronic T1 Crystal nucleation in metallic alloys using x-ray radiography and machine learning JF Science Advances JO Sci Adv FD American Association for the Advancement of Science SP eaar4004 DO 10.1126/sciadv.aar4004 VO 4 IS 4 A1 Liotti, Enzo A1 Arteta, Carlos A1 Zisserman, Andrew A1 Lui, Andrew A1 Lempitsky, Victor A1 Grant, Patrick S. YR 2018 UL http://advances.sciencemag.org/content/4/4/eaar4004.abstract AB The crystallization of solidifying Al-Cu alloys over a wide range of conditions was studied in situ by synchrotron x-ray radiography, and the data were analyzed using a computer vision algorithm trained using machine learning. The effect of cooling rate and solute concentration on nucleation undercooling, crystal formation rate, and crystal growth rate was measured automatically for thousands of separate crystals, which was impossible to achieve manually. Nucleation undercooling distributions confirmed the efficiency of extrinsic grain refiners and gave support to the widely assumed free growth model of heterogeneous nucleation. We show that crystallization occurred in temporal and spatial bursts associated with a solute-suppressed nucleation zone.