Investigation of the Notch Angle Effect on Charpy Fracture Energy in 7075-T651 Aluminum Alloy

In the present study, the Charpy impact test was performed on 7075-T651 Aluminum alloy specimens with different notch angles for fracture energy measurement. In this regard, specimens with seven different notch angles were prepared, and then fracture energy was measured using the Charpy impact test. By considering the experimental results a quadratic relationship between the fracture energy (CVN in J) and the notch angle of the Charpy specimens was achieved for the tested Aluminum alloy, so the fracture energy of the 7075-T651 AA specimens was calculated for each desired notch angle. The experimental data validation was performed using mathematical modeling. Furthermore, the fracture surface of the specimens was investigated at different notch angles using SEM. By increasing the notch angle to the standard specimen, the fracture surface becomes smoother and tends to feature a brittle fracture as well as the shear lip is reduced. Moreover, for the specimens with higher notch angle (from the standard), the fracture surface tends to feature a ductile fracture and the shear lip increases.