Fruehstadien der Phasenbildung im System Titan-Aluminium

Intermetallic alloy based materials for structural applications can be produced by powder metallurgical methods, where the intermetallic compounds are formed by a solid state reaction between the elemental components. In the Ti-Al system, the early stages of this solid state reaction is characterized by a distinct phase selection in favor of TiAl_3, whereas the other intermetallic compounds are not observed. Layered structures were designed with a layer of the intermetallic #alpha#_2- or #gamma#-phase between the elemental Ti and Al layers. Upon solid state reaction TiAl_3 grows at the expense of #alpha#_2 or #gamma#, respectively, until they disappear complete. A kinetic model is presented, which explains the observed phase selection on the basis of different growth velocities of the competing phases. It permits optimization of the powder metallurgical reaction used to form intermetallic based materials. (orig.)65 refs.Available from TIB Hannover: RA 3251(95/E/6) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman