EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

"The solidification behavior of a eutectic AlCu specimen is investigated via in situ scanning transmission electron microscope (STEM) experiments. Solidification conditions are varied by imposing various cooling rates via a micro-electro-mechanical system (MEMS) based membrane. The methodology allows the use of material processed by a melting and casting route close to industrial metallurgically fabricated material for in situ STEM solidification studies. Several rapid solidification morphologies could be obtained solely on a single specimen by the demonstrated strategy. A change from nanometer scaled lamellar to dendritic morphology is observed by differing cooling from medium to the highest tested rates. Cooling rates of 100, 10000 and 30000 K/s are used. For the comparatively slow cooling rate of 100 K/s, a coarser three-dimensional morphology is gained. Additional post-solidification heat treatments are investigated in terms of observation of spheroidization of lamellas during annealing at elevated temperatures." [arXiv:2101.02935]