Origin of excellent mechanical properties of highly-concentrated alloys

Tsuru, Tomohito   ; Lobzenko, I.   

High-entropy alloys (HEAs) are defined as alloys with a crystal structure consisting of a mixture of five or more elements in high concentration. However, the mechanism of the observed simultaneous increase in strength and ductility and the excellent mechanical properties of some HEAs has not been understood. In the present study, the origin of the mechanical properties of HEA was investigated by atomistic simulations based on first-principles calculations. As a result, the local lattice distortion and the formation of short-range order (SRO) structure were reproduced in alloy systems with FCC structure. It was found that in some alloy systems, a significant change in stacking fault energy for SRO formation contributes to the improvement of macroscopic mechanical properties.