Abstract Scope |
The body-centered-cubic (BCC) refractory high-entropy alloys (RHEA), which are composed of four or more refractory metal elements (Mo, Nb, Ta, W, V, Zr, and Hf), were reported to have superior yield strength at elevated temperatures above 1100K. To understand the role of dislocations in the mechanical properties of these alloys, we investigate the fundamental properties of both edge and screw dislocations using atomistic simulations with state-of-art machine-learning interatomic potentials. Particularly, we analyze the dislocation energies, core structure, and Peierls stress in the NbMoTaW BCC high-entropy alloy, compared with the existing experimental evidence. The free energies of dislocations are computed to examine the potential impact of temperature on the relative stability between edge and screw dislocations. Additionally, tensile stress simulations are carried out using systems to study dislocation initiation from grain boundaries. |