Elemental Distribution in CrNbTaTiW-C High Entropy Alloy Thin Films
Journal article, 2019

The microstructure and distribution of the elements have been studied in thin films of a near-equimolar CrNbTaTiW high entropy alloy (HEA) and films with 8 at.% carbon added to the alloy. The films were deposited by magnetron sputtering at 300°C. X-ray diffraction shows that the near-equimolar metallic film crystallizes in a single-phase body centered cubic (bcc) structure with a strong (110) texture. However, more detailed analyses with transmission electron microscopy (TEM) and atom probe tomography (APT) show a strong segregation of Ti to the grain boundaries forming a very thin Ti-Cr rich interfacial layer. The effect can be explained by the large negative formation enthalpy of Ti-Cr compounds and shows that CrNbTaTiW is not a true HEA at lower temperatures. The addition of 8 at.% carbon leads to the formation of an amorphous structure, which can be explained by the limited solubility of carbon in bcc alloys. TEM energy-dispersive X-ray spectroscopy indicated that all metallic elements are randomly distributed in the film. The APT investigation, however, revealed that carbide-like clusters are present in the amorphous film.

thin film

high entropy alloy

segregation

atom probe tomography

carbon clustering

Author

Deodatta Shinde

Chalmers, Physics, Materials Microstructure

Stefan Fritze

Uppsala University

Mattias Thuvander

Chalmers, Physics, Materials Microstructure

Paulius Malinovskis

Uppsala University

Lars Riekehr

Uppsala University

U. Jansson

Uppsala University

Krystyna Marta Stiller

Chalmers, Physics, Materials Microstructure

Microscopy and Microanalysis

1431-9276 (ISSN) 1435-8115 (eISSN)

Subject Categories

Inorganic Chemistry

Materials Chemistry

Condensed Matter Physics

DOI

10.1017/S1431927618016264

More information

Latest update

2/13/2019