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M: Metallphysik

M 31: Intermetallische Phasen I

M 31.1: Vortrag

Mittwoch, 26. März 2003, 14:45–15:00, IFW B

Microstructural aspects of diffusion bonding of high niobium containing gamma TiAl-based alloys — •Cesar Buque und Fritz Appel — GKSS Forschungszentrum, Institut fuer Werkstoffforschung, 21502 Geesthacht

Microstructural aspects of diffusion bonding of high niobium containing gamma TiAl-based alloys C. Buque, F. Appel The paper describes a detailed analysis of diffusion bonding (DB) of a Ti-45Al-10Nb representing a new generation of TiAl alloys with enhanced high-temperature capability. The study involves scanning electron microscopy coupled with chemical microanalysis and electron backscattered diffraction. DB of this alloy results in the formation of Alpha-2 Ti3Al grains at the bonding interface surrounded by gamma-TiAl grains. In few cases the formation of ß/B2 small particles was also found. Nucleation of the Alpha-2 grains occurs at the expense of the Alpha-2 lamellae and probably involves migration of antisite defects via anti-structural bridges. Remnant deformation structures and the occurrence of a 10-10-texture of the Alpha-2 grains suggest that the recrystallisation processes are driven by localised deformation. These results will be compared with those found by DB of binary alloys with regard to the basic mechanisms involved and discussed with respect to the optimisation of bonding parameters towards improved bond strengths.