Decomposition in multi-component AlCoCrCuFeNi high-entropy alloy

The decomposition of an equiatomic AlCoCrCuFeNi high entropy alloy produced by splat quenching and casting was investigated by the analytical high resolution methods transmission electron microscopy and three-dimensional atom probe It could be shown that splat-quenched alloy consisted of an imperfectly ordered body-centred cubic phase with a domain-like structure, whereas normally cast alloy formed several phases of cubic crystal structure The cast alloy decomposed into both dendrites and interdendrites A detailed local compositional analysis carried out by atom probe within the dendrites revealed that the alloying elements in the Ni-Al-rich plates and Cr-Fe-rich interplates are not randomly distributed, but segregate and form areas with pronounced compositional fluctuations Cu-rich precipitates of different morphologies (plate-like spherical and rhombohedron-shaped) could also be found in the dendrites The results are discussed in terms of segregation processes governed by the enthalpies of mixing of the binary systems (C) 2010 Acta Materialia Inc Published by Elsevier Ltd All rights reserved