|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Gamma (FCC)/Gamma-Prime (L12) Co-Based Superalloys II
||Solute-vacancy Binding Energies and Diffusion Rates in fcc Cobalt: A First-principles Database
||Shahab Naghavi, Vinay Hegde, Chris Wolverton
|On-Site Speaker (Planned)
Understanding solute-vacancy interactions and diffusion of solutes is crucial for the design of novel cobalt-based superalloys. Despite their importance, relatively little experimental and theoretical data is available for the above properties. Here, we present accurate first-principles calculations of solute-vacancy (SV) binding energies and diffusion rates of various solutes in fcc cobalt. Using density functional theory (DFT), we compile a database of SV and diffusivities of all 3d, 4d and 5d transition metals in fcc cobalt. Our calculations reveal a systematic relationship between solute-vacancy binding energies and solute diffusion with d-occupancy of the solute, explained by the d-band model. Both the properties are the largest for elements at the far-right and far-left of the d-block of transition metals, and decrease toward the middle of the series. We also find that magnetism has a profound effect on the diffusion rates, whenever applicable.