FLEXURAL STRENGTH OF GAMMA-BASE TITANIUM ALUMINIDES AT ROOM AND ELEVATED-TEMPERATURES

The influences of microstructure, alloying additions and processing me thod on the flexural strength and fracture behavior of gamma base tita nium aluminides were investigated at room and elevated temperatures. T he flexural strength strongly depends on the microstructure, alloying addition and processing method. The lamellar microstructure material e xhibited high strength and ternary chromium or niobium addition improv ed the strength. Isothermal forging resulted in a fine grain microstru cture and influenced the bend properties. The flexural strength increa sed up to a 'critical temperature' and thereafter it decreased. This ' critical temperature' seemed to depend on the chemical composition. Th e room-temperature fracture was mostly transgranular cleavage and inte rgranular fracture regions were dominant with increasing temperature. At high temperatures ductile tearing was observed, irrespective of the microstructure.