Dynamic fracture toughness of a near alpha titanium alloy Timetal 834

The dynamic fracture toughness of Timetal 834 alloy under impact loading was evaluated using fatigue pre-cracked specimens and compared with the fracture toughness under static loading condition evaluated in an earlier study. It was found that the dynamic fracture toughness under impact loading was higher than the fracture toughness value under static loading conditions. This behaviour was attributed to the effect of strain rate on strain hardening exponent and yield strength. The effect of notch root radius on dynamic fracture toughness of this alloy was also studied. It was found that there exists a critical notch radius (ρ0) of ∼150 μm below which the dynamic fracture toughness was independent of notch root radius. Above ρ0, the dynamic fracture toughness increased linearly with square root of notch root radius.