Fachbereich 11 - Physik
Institut für Materialphysik
Diffusion in Metals, Intermetallics, Silicides, Quasicrystals and Metallic Glasses

Diffusion in binary Al-Ni and ternary Al-Ni-Fe intermetallic compounds

Intermetallic compounds on Al-Ni and Al-Ni-Fe are prominent high temperature alloys suitable for advanced technological applications. The knowledge of the diffusion characteristics and fundamental understanding of diffusion mechanisms are of great importance to the research and design of industrial materials. From the theoretical point of view the B2-structured intermetallic compounds NiAl and (Ni,Fe) Al are textbook-like systems for fundamental investigations due to the compositionally extended range of Ni-rich as well as Al-rich alloys forming antisite defects and high concentrations of constitutional vacancies, respectively. We have investigated the temperature and compositional dependence of Ni and Fe diffusion in NiAl and (Ni,Fe) Al alloys using the radiotracer technique and also SIMS analysis. Applying additionally embedded-atom potential calculations and Monte Carlo simulation it was clearly shown that the triple defect mechanism dominates the Ni- and Fe-diffusivity in a wide concentration range while the previously often discussed six-jumps-cycle mechanism is negligible due to strong correlation effects.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Dr. S. V. Divinski, Prof. Dr. Chr. Herzig (Leiter), Dr. F. Hisker, Dipl.-Phys. Y. S. Kang, Dr. U. Södervall (Chalmers University of Technoglogy)

Veröffentlichungen:

Frank, St., S. V. Divinski, U. Södervall, Chr. Herzig: Ni tracer diffusion in the B2-compound NiAl: influence of temperature and composition, Acta mater., 49, 1399 (2001)

Divinski, S. V., St. Frank, U. Södervall, Chr. Herzig: Tracer measurements of Ni self-diffusion and atomistic calculations of diffusion mechanisms in NiAl, Defect and Diffusion Forum, 194 - 199, 1127 (2001)

Divinski, S. V., Chr. Herzig: Ni tracer diffusion, interdiffusion and diffusion mechanisms in NiAl, Defect and Diffusion Forum, 203 - 205, 177 (2002)