Exploring the high entropy alloy concept in (AlTiVNbCr)N

Publication date: 31 August 2017
Source:Thin Solid Films, Volume 636
Author(s): K. Yalamanchili, F. Wang, I.C. Schramm, J.M. Andersson, M.P. Johansson Jöesaar, F. Tasnádi, F. Mücklich, N. Ghafoor, M. Odén
We have explored the high entropy alloy (HEA) concept in the AlTiVNbCr-nitride material system. (AlTiVNbCr)N coatings synthesized by reactive cathodic arc deposition are close to an ideal cubic solid solution with a positive mean-field enthalpy of mixing of 0.06eV/atom. First principle calculations show a higher thermodynamic stability for the solid solution relative to their binaries thereby indicating a possible entropy stabilization at a temperature above 727°C. However, the elevated temperature annealing experiments show that the solid solution decomposes to w-AlN and c-(TiVNbCr)N. The limited thermal stability of the solid solution is investigated in relation to several thermodynamic parameters. We suggest that the HEA designed multiprincipal element (AlTiVNbCr)N solid solutions are in a metastable state.