Tracer diffusion of cobalt in high-entropy alloys AlxFeNiCoCuCr

Abstract

The Co diffusion in the as-cast high-entropy alloys AlxFeNiCoCuCr (x = 1, 1.5, 1.8) is studied by means of the tracer-diffusion method using the 60Co isotope. As shown, the Co diffusion in the high-entropy alloys occurs by means of the vacancy mechanism and the diffusion coefficient decreases approximately in three times (from 3.21.10-16 to 0.98.10-16 m2.s-1) with the increasing Al concentration. The decelerated Co diffusion is explained in terms of relatively large and negative enthalpy of mixing.