KINETIC MONTE CARLO SIMULATION OF DISLOCATION SOLUTE INTERACTIONS IN MULTI COMPONENT ALLOYS

Abstract

In Co-based superalloys, high temperature deformation is controlled by glide of dislocations with a solute atmosphere around them [1]. A gain in strain energy drives the formation of the solute clouds which are kinetically controlled by atomic diffusion. As the drag offered by the solute atmospheres to dislocation motion at elevated temperatures determine the rates of creep deformation, it is essential to do a detailed study of dislocation motion when the solute atoms are diffusing and interacting with the dislocations. A Kinetic Monte Carlo model is developed to simulate edge dislocation motion in the presence of solute atoms that are diffusing and interacting with it through their respective strain fields. Our simulations can determine the dislocation velocity and solute concentration profile around the dislocation self-consistently. At low velocity the moving dislocation will be associated with a solute atmosphere, while at high velocity no solute clouds will form. Through our simulations, we predict the degree of solute cloud formation around the edge dislocation and develop the functional relationship between its velocity and resolved shear stress on the glide plane. We also derive qualitative guidelines from our simulations which can be used to design novel creep resistant alloys.