EFFECTS OF LAMELLAR BOUNDARIES ON CREEP BEHAVIOR OF PST CRYSTALS OF TiAl ALLOYS
(Department of Materials Science and Engineering,Beijing University of Aeronautics and Astronautics, Beijing100083, P. R. China)
Abstract: TiAl PST crystals were grown using an induction floating zone melting furnace. The creep behavior and deformation structure at 800℃were studied for the samples with three orientations. The results indicate that the creep behavior of PST crystals is strongly dependent on the lamellar orientation with respect to the loading axis. The presence of lamellar boundaries influences the creep deformation. They may not only inhibit shear deformation across the lamellae, but also pin the dislocation and restrict its motion.
Key words: TiAl alloy PST crystal creep behavior deformation twin