SKM 2023 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 18: Transport in Materials: Metals, Alloys and Oxides
MM 18.6: Vortrag
Dienstag, 28. März 2023, 12:45–13:00, SCH A 118
Impact of alloying elements on point defects and diffusion in B2 alloys: an ab initio study — •Aditya Vishwakarma1, Osamu Waseda1, Tilmann Hickel1, Neelamegan Esakkiraja2, Sergiy Divinski2, and Aloke Paul3 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 2Institute of Materials Physics, University of Münster, Germany — 3Department of Materials Engineering, IISc Bangalore, India
Turbine blades in jet engines are vulnerable to many problems due to the harsh application environments. To prevent oxidation and surface degradation, bond coats of B2 NiAl are most widely used. During the operation at high temperatures, however, the Al content in the bond coat is lost by the formation of an Inter Diffusion Zone (IDZ) between the superalloy (turbine blade) and the bond coat. In this report, ab-initio based studies of point defect formation and kinetics are performed, in order to investigate the diffusion mechanisms and the impact of alloying elements on diffusion in B2 NiAl phase. Our results show that isoelectronic substitutions by Pt and Pd decreases the triple defect migration barriers and increases the Ni vacancy concentration in comparison to pure B2 NiAl. Accordingly, the contribution of the triple defect mechanism increases down the periodic table. These results explain the experimentally observed increase of the thickness of IDZ compared to binary B2 NiAl and have, therewith, an impact on the future design of turbine blades.