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

Multiphase diffusion in binary Al-Mg alloys

The Al--Mg system on the Al-rich side is the basis for a widely used class of non-heattreatable Al-alloys containing up to a few percent Mg and on the Mg-rich side the basis of Mg die-casting alloys with a few percent Al, which are widely used as automotive components. Phase formation and diffusion are important topics of the materials science of these alloys. We investigated diffusion couples between Al and Mg to study the formation, composition and growth kinetics of intermetallic phases in the Al-Mg system. Layers of two intermetallic compounds were observed by optical microscopy. Composition-depth-curves were determined by electron microprobe analysis across the diffusion zones. The solid-solid phase equilibria of the Al-Mg system were redetermined. Parabolic growth kinetics of both phases was observed in the whole temperature range investigated. The growth of Al₃Mg₂ is faster than that of Al₂Mg₁₇ by about oneorder of magnitude. The pertaining activation enthalpies of growth were determined.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Prof. Dr. H. Mehrer (Leiter), Dipl.-Phys. M. Salamon, Dipl.-Phys. E. M. Tanguep Njiokep

Veröffentlichungen:

Tanguep Njiokep, E. M., M. Salamon, H. Mehrer: Growth of intermetallic phases in the Al-Mg system, Defect and Diffusion Forum 194 - 199, 1581 - 1586 (2001)