|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Late News Posters
||PP-3: A Systematic First-principles Study of Diffusion Mechanisms in 26 Dilute Ni-X Alloy Systems
||Chelsey Zacherl Hargather, ShunLi Shang, Zi-Kui Liu
|On-Site Speaker (Planned)
||Chelsey Zacherl Hargather
Temperature-dependent diluter tracer diffusion coefficients are calculated for 26 transition metal alloying elements in fcc Ni using the five-frequency model for dilute diffusion using first-principles calculations based on density functional theory. Calculations are performed within the spin-polarized local density approximation. The nudged elastic band method is used to calculate the minimum energy pathways of the solute atoms. Thermodynamic properties at finite temperatures are calculated using the quasi-harmonic Debye model. The 3d transition metal solutes are the fastest diffusers in fcc Ni while the 5d transition metals solutes are the slowest. Three mechanisms contributing to dilute tracer diffusion: vacancy formation energy, solute-vacancy binding energy, and solute migration barrier are examined for each of the 26 alloy systems at T=1000 K. Diffusivity shows the strongest correlation to the solute migration barrier. Finally, diffusivity results are discussed in reference to improving the understanding of alloying element behavior in Ni-base superalloy systems.