Abstract:

Solid solution strengthening is a classical metallurgical process that has been brought to the center stage by the development of high entropy alloys. Solutes may affect dislocations at different levels, from their core structure to their long-range glide, depending on the alloy considered, the solutes’ position (interstitial or substitutional), concentration, short-range ordering, …
In this talk, we will illustrate several solute effects on dislocations, both at short- and long range. We will show, based on ab initio calculations, how interstitial solutes can reconstruct the core of screw dislocations in BCC metals, dramatically reducing their mobility. At a larger scale, we will see based on elasticity that the stress field in a random alloy shows anisotropic spatial correlations that affect differently dislocations of different characters and need to be included in models of solute solution strengthening.