Dresden 2017 – scientific programme

Parts | Days | Selection | Search | Updates | Downloads | Help

MM: Fachverband Metall- und Materialphysik

MM 34: Poster session II

MM 34.12: Poster

Tuesday, March 21, 2017, 18:30–20:30, P4

Ab initio investigation of Re-Re interactions in Ni-base superalloys — •Maximilian Grabowski, Jutta Rogal, and Ralf Drautz — ICAMS, Ruhr-Universität Bochum, 44801 Bochum, Deutschland

Ni-base superalloys are widely used in high-temperature applications e.g. in turbine blades for jet engines of aeroplanes. In these applications, the materials have to perform at high temperature and high stress. Ni-base superalloys have a complex composition where one of the key ingredients is Re, which significantly improves the mechanical behaviour.

Using density functional theory (DFT) calculations we investigate the Re-Re interaction in Ni with a particular focus on the role of magnetism. The nearest neighbour Re-Re interaction in the nonmagnetic and in the ferromagnetic configuration exhibit a qualitatively different behaviour from strongly repulsive to weakly attractive. We show that this is mainly due to a decrease of the Ni magnetic moment in the vicinity of Re and discuss possible consquences for the clustering of Re in Ni-based superalloys. In a next step we investigate the mobility of Re in Ni in concentrated Ni-Re alloys. As a basis for our dynamical simulations, we use a cluster expansion (CE) to evaluate the energies of the binary Ni-Re and the ternary Ni-Re-Vacancy system. DFT calculations are used to determine the effective cluster interactions (ECI) for the CE. We will also report on our progress of a CE for the diffusion barriers, which -when converged- enables us to predict diffusion in concentrated Ni-Re alloys from first-principles calculations.