Manzoni, A.M.; Glatzel, U.: New multiphase compositionally complex alloys driven by the high entropy alloy approach. Materials Characterization 147 (2019), p. 512-532

The discovery of high entropy alloys at the turn of the millennium lead to a multitude of investigations of different types, focus and aims. With an increased knowledge of the new family of materials, it was possible to make a separation into true single phase high entropy alloys (HEA) and multi-phase compositionally complex alloys (CCA), which both fulfil the initial definition criteria. This review focuses on CCA that have been investigated and developed with a mechanical application in mind. A special importance is attributed to the mechanical testing methods, and priority is given to tensile testing at both room temperature and up to 700 °C. Precise microstructural characterization techniques like transmission electron microscopy and/or atom probe tomography ensure the determination of small scale phases, which could be overlooked when using only scanning electron microscopy and/or X-ray diffraction. Comparison of the investigations that meet these criteria are summarized in several tables and figures.