Seminars and Events

Vacancy mobility and interaction with transition metal solutes in Ni

Date/Time: 16.09.2014. 12:15 p.m.
Place: International workshop on modelling and simulation of superalloys, Bochum, Germany

Sergej Schuwalow, Department of Atomistic Modelling and Simulation, Ruhr-Universität Bochum, Bochum

The dependence of high-temperature properties of Ni-based superalloys on the alloying additives is a subject of ongoing research. Current knowledge is mostly phenomenological in nature and the details of solute diffusion, interaction with defects, and the interplay between composition and microstructure are not well understood. Within this work interaction of Re, Ta, W and Mo solutes with vacancies and their diffusion in fcc Ni is investigated by density-functional theory (DFT) in combination with kinetic Monte Carlo (kMC) simulations. We calculate solute-vacancy interaction energies and macroscopic diffusion coefficients for the four elements in Ni as well as for vacancies themselves in the presence of these elements. The calculated solute diffusion coefficients are found to compare favorably to experimental values. The mobility of the vacancies as a key factor in dislocation climb is found to be only minimally influenced by the solute atoms within the dilute limit.

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