Thermal Stability of Superhard Nitride Coatings from High-Entropy Multicomponent Ti-V-Zr-Nb-Hf Alloy

Nitride coatings with high hardness (60.0-65.0 GPa) are produced from a high-entropy multicomponent single-phase alloy containing five nitride-forming elements by vacuum arc deposition with application of pulsed implantation. These high values of hardness are characteristic of metals in the equiatomic alloy only in nanostructured state. The mechanical properties of the coatings annealed in the temperature range up to 1200 A degrees C are studied. It is established that the coatings are solid solutions of high-entropy nitride with fcc lattice. The vacuum coatings inherit the same type of crystal lattice as that of the target (bcc). The crystal lattice of high-entropy vacuum coatings is formed through the mechanism revealed in the cast alloys. The parameter of this lattice is close to that calculated by Vegard's rule.