Elucidating the roles of chemistry, compositional complexity, and short-range order in the dislocation energetics of body-centered-cubic concentrated solid solutions

Dislocation-mediated deformation mechanisms in body-centered-cubic solid solutions are expected to be influenced by spatial fluctuations in screw dislocation core energies. In refractory high-entropy alloys, the formation of chemical short-range order has been demonstrated to decrease the heterogeneity of this energy landscape, narrowing the distribution of dislocation core energies. It is, however, unclear if multicomponent compositionally complex systems display any unique effects or if these results are more generally applicable. To answer this question, this study computationally investigates how system chemistry, compositional complexity, and the presence of various degrees of chemical short-range order affect the distribution of screw dislocation energies in binary and ternary subsystems of the NbMoTaW alloy. We report the calculated averages and variances for the diffuse antiphase boundary energy and the dislocation core energy with various degrees of chemical short-range order. While short-range order negligibly affects the average core energies, their distributions are notably narrowed in some, but not all, systems, primarily depending on chemistry rather than the number of components.