Real-time growth studies of high-entropy alloy thin films: phase formation and stress evolution

This project aims to gain physical knowledge on the mechanisms taking place during the early nucleation and growth stages of high-entropy alloy (HEA) and high-entropy nitride (HEN) thin films, hitherto only partly investigated by theoretical studies.

The proposed experimental investigation is a unique, original approach that will rely on both the kinetics and the reactivity of the thin film growth process and will be achieved, for the first time in HEA/HEN films, using in situ and real-time electrical (sheet resistance) and optical (wafer curvature) nanoscale diagnostics, the latter being also capable to provide reliable information on the intrinsic stress of the produced material.

Ex situ post-growth microstructural evaluation will be also considered, as well as the film synthesis conditions prevailing on their phase formation and mechanical properties.

Two HEA that find applications in areas of importance for society will be studied: the CoCrFeMnNi and MoNbTaVW, which are archetypes of fcc- and bcc-forming systems, respectively.

The former is the most studied HEA, known for its outstanding mechanical properties even in cryogenic environments, whereas the latter is an advanced refractory alloy with high-temperature strength and stability. This postdoctoral fellowship will be carried out by the applicant Felipe Cemin under the supervision of Prof.

Gregory Abadias at Pprime Institute (host), CNRS/University of Poitiers/ISAE-ENSMA (Poitiers, France).