On the single phase fcc solid solution in nanocrystalline Cr-Nb-Ti-V-Zn high-entropy alloy

• A face centered cubic structure is realized in Cr-Ti-Nb-V-Zn system during milling.
• A lattice parameter of 4.2 Å was obtained in this complex solid solution suggesting that it was an expanded lattice.
• It appears that presence of Zn is governing the formation of FCC solid solution in this system comprising of no fcc element.
• The suggested guidelines of phase formation in high entropy alloys have not been followed by this material system.

A single phase fcc solid solution, with a lattice parameter of 4.20±0.01 Å and a crystallite size of 7±2 nm (TEM), has been observed in an equiatomic nanocrystalline Cr-Nb-Ti-V-Zn high-entropy alloy during mechanical alloying. Uniqueness of this work is that an fcc solid solution was observed in a system where none of the elements is fcc. This system obeys the guiding principles laid down for high entropy alloys based on atomic size difference, ΔHmix and ΔSmix. However it does not obey the guidelines based on valence electron concentration.