A. Wang; L. Pethö; Z. Hegedűs; M. Wątroba; J. Michler; J. Veselý; P. Minárik; P. Nagy; J. Gubicza
Journal of Alloys and Compounds 1048 (2025) 185264
Experiments were conducted to study the structure and mechanical behavior of high-entropy alloys (HEAs) in the
Co-Cr-Fe-Mo-Ni-W compositional library. This investigation was performed on a 3 μm thick combinatorial thin
film deposited on a single crystal silicon (c-Si) substrate by magnetron sputtering technique. The chemical
composition for each element varied in the range of about 5–40 at%. The mapping of the structure was carried
out by synchrotron X-ray diffraction while the mechanical behavior was studied by nanoindentation. A com
plementary transmission electron microscopy investigation at some selected compositions was also performed.
Most of the studied compositions formed an amorphous structure while nanocrystalline body-centered cubic
(bcc) and hexagonal close-packed (hcp) phases were detected in the vicinity of W/Mo and Co/Ni elemental
sources, respectively. The hcp structure contained a very high density of stacking faults on the basal planes. The
variation of the phase composition can be related to the change of valence electron concentration. The lattice
constants in the crystalline regions of the combinatorial sample changed in accordance with the variation of the
average atomic radius. The combinatorial sample contained pores which significantly reduced the hardness. The
highest hardness values (7.8 ± 0.3 GPa) were detected in the bcc region for the compositions of 8.1 % Co –
25.6 % Cr – 6.9 % Fe – 16.4 % Mo – 9.1 % Ni – 33.9 % W (at%).