Phase evolution in an Al0.5CrFeCoNiCu High Entropy Alloy

The phase evolution of an Al0.5CrFeCoNiCu High Entropy Alloy has been characterised following isothermal exposures between 0.1 and 1000 hat temperatures of 700, 800 and 900 degrees C. The NiAl based B2 phase formed extremely quickly, within 0.1 h at the higher exposure temperatures, whilst the Cr-rich sigma phase formed more slowly. The solvus temperatures of these two phases were found to be similar to 975 and similar to 875 degrees C respectively. Compilation of the data presented here with results previously reported in the literature enabled the production of a time-temperature-transformation diagram, which clearly indicates that the diffusion kinetics of this material cannot be considered sluggish. (C) 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).