Dynamic fracture behaviour of AA7475-T7351 alloy at different strain rates and temperatures

The fracture behaviour of the aluminium alloy AA7475-T7351 at different loading rates and temperatures (-150 degrees C to 200 degrees C) is investigated here. The three-point bend experiments are conducted at Zwick/Roell-50 UTM (crosshead speed up to 100 mm/min), MTS-250 machine (crosshead speed upto 1000 mm/min) and modified Hopkinson pressure bar (striker velocity 11-19 m/s) to understand the initiation and propagation fracture toughness of AA7475-T7351 aluminium alloy along the rolling (L-T) and transverse (T-L) directions. The digital image cor-relation (DIC) technique is used to obtain the load point displacement (LPD) and crack mouth opening displacement (CMOD) and the same is used to calculate the stress intensity factor (SIF). The fracture surface is studied using a digital stereo microscope (DVM6) and scanning electron microscope (SEM). The fracture toughness of AA7475-T7351 is found to depend on the loading rates and temperatures and found to vary between 50 and 66 MPm1/2 along the L-T direction, whereas the corresponding value along the T-L direction is comparatively less.