Accelerated atomic-scale exploration of phase evolution in compositionally complex materials

Yujiao Li, ZGH and Ruhr-University Bochum, Bochum, Germany

The design of compositionally complex materials, like multiple principal element alloys, requires knowledge of the complete phase space of the constituents of a multinary system, i.e. which phases form or decompose at different processing conditions. The acquisition of this knowledge is accelerated by a new combinatorial processing platform (CPP) approach [1], which enables: simultaneous synthesis of 36 identical atomic-scale-mixed films by co-deposition of 5 elements on an array of 10-nm-diameter Si tips; rapid phase evolution in the formed nanoscale reactors upon processing; direct atomic-scale analysis of phase evolution after each processing step by atom probe tomography, complemented by transmission electron microscopy. Results from nanocrystalline CrMnFeCoNi show that this alloy is unstable and already decomposes after 1 h at low temperatures of around 300 °C. The approach is extendible to explore oxidation and corrosion in complex materials on the atomic scale.

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