Interface diffusion in intermetallic compounds

The kinetic behaviour of atoms in grain- and interpase boundaries of intermetallic compounds was not much studied experimentally so far. Only some model calculations on the structure of interface boundaries taking into account the particular lattice structure and the ordering energy are available for some compounds like Ni₃Al, NiAl and TiAl. The evaluation of the grain boundary diffusivity requires the knowledge of the lattice diffusivity, first of all, which was measured in our group in current projects in titanium- and nickel aluminides. In continuation of these bulk diffusion studies we therefore investigated titanuim tracer diffusion in the compounds a₂-Ti₃Al and g-TiAl and, due to the great practical importance, also interphase boundary diffusion in a/₂/g interphases on samples with unidirectional a/₂/g interphase orientation. First experiments were also performed on Ni grain boundary diffusion in NiAl. A district systematic behaviour of the Ti diffusivity was found in the Ti-Al system.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Dr. A. Bartels (Technische Universität Hamburg-Harburg), Dr. S. V. Divinski, Dr. St. Frank, Prof. Dr. Chr. Herzig (Leiter), Dipl.-Phys. F. Hisker, Dr. T. Przeorski

Veröffentlichungen:

Herzig, Chr., S. V. Divinski, St. Frank, T. Przeorski: Bulk and grain boundary diffusion in intermetallic compounds of the systems Ni-Al and Ti-Al, Mat. Sci. Forum, in print

Divinski, S. V., F. Hisker, A. Bartels, Chr. Herzig: Interphase boundary diffusion of ⁴⁴Ti in two-phase TiAl with lamellar a₂/g structure, Scripta Materialia, in print

Herzig, Chr., T. Wilger, T. Przeorski, F. Hisker, S. V. Divinski: Titanium tracer diffusion in grain boundaries of a-Ti, a₂-Ti₃Al, and g-TiAl and in a₂/g interphase boundaries, Intermetallics, in print