The relation between the nanostructure and the mechanical properties of Nb-x-CoCrCuFeNi
high entropy alloy thin films was explored. With increasing Nb concentration (0 to
24 at.% Nb), a transition from a single phase face-centered cubic solid solution to
an amorphous phase is observed. At intermediary Nb fractions (5 to 15 at.% Nb) a nanocomposite
structure is formed that consists of nanosized crystallites embedded in an amorphous
matrix. The nanocomposite structure leads to an increase in hardness beyond the Hall-Petch
breakdown. The shear and Young's moduli decrease with increasing Nb concentration,
which is beneficial for the alloy ductility. (C) 2017 Acta Materialia Inc. Published
by Elsevier Ltd. All rights reserved,
