Solid solution strengthening of the body-centered cubic refractory complex concentrated alloy, MoNbTaW

Abstract

In this manuscript, experimental yield stress data as a function of temperature of the body-centered cubic refractory complex concentrated alloy MoNbTaW are analyzed using two solid solution strengthening models: the Rao-Suzuki model (screw strengthening) and the Maresca-Curtin model (edge strengthening). It is shown that the Rao-Suzuki model results are in reasonable agreement with the experimental yield data whereas the Maresca-Curtin model underpredicts the strengthening. Similarly, molecular dynamics data on the critical stress to move screw and edge dislocations in MoNbTaW are analyzed using the Rao-Suzuki and the Maresca-Curtin models, respectively. It is shown that the molecular dynamics edge mobility results are in reasonable agreement with the Maresca-Curtin model whereas the molecular dynamics simulated data on the critical stress to move screw dislocations in MoNbTaW severely overpredicts the Rao-Suzuki model. This is argued to be a result of the very small dislocation line lengths used in the molecular dynamics simulations, ∼150A.