Six alloys which compositions contained the elements of Co, Cr, Fe, Ni and Ti were cast by arc melting, and examined their microstructures, mechanical properties, thermoelectric properties, analyzed the influence for property of microstructures. The results indicated that (1) increasing the elements of these alloys, atomic size of the atoms were more different, it was also easily to produce the high-entropy alloys with higher hardness; (2) the structure of CoCrFeNi high-entropy alloys was FCC, and its hardness was HV163, this revealed that the high-entropy alloys also could be designed to produce the alloys with lower hardness; (3) the microstructures of these a high-entropy alloys had nano-scale microstructures by TEM observing, and the grain sizes are about several nm. CoCrFeNi alloy also showed a microstructure of nano-grain with superlattice; and (4) the oxide resistance of high-entropy alloys were measured by TGA revealed that these six alloys all have higher oxidization resistance.
