The most commonly investigated high entropy alloys, or compositionally complex alloys, belong to the Al-Co-Cr-Cu-Fe-Ni group. After investigation for over a decade only few alloys are candidates for industrial application, often because of their low ductility. One ductile alloy, Al8Co17Cr17Cu8Fe17Ni33, has been chosen for deeper investigation. The dendritic segregation into Co-Cr-Fe rich cores and Al-Cu-Ni rich interdendritic sites can be homogenized and annealed as to form a two-phase alloy with Al-Cu-Ni rich precipitates of L12 structure inside a solid solution matrix.
Trace elements W, Mo and Ti, known as γ' stabilizers from Ni-based alloys, have been added to the alloy because, according to ThermoCalc, they increase the melting point and the γ-γ' phase transition temperature .
Transmission and scanning electron microscopy and three dimensional atom probe have been used to investigate the as-cast, homogenized and annealed states. The results of the investigations will be compared with ThermoCalc predictions.