Quasi-static and Dynamic Fracture of High-strength Aluminium Alloy

The quasi-static and dynamic fracture behaviour of the high-strength aluminium alloy AA7075-T651 was studied by material testing over a wide range of stress states and dynamic impact testing using different shapes of the projectile. Rolled plates of the aluminium alloy exhibited anisotropy owing to the complex, non-recrystallized microstructure. In the quasi-static tests, a marked influence of loading direction on the fracture strain was observed, in addition to the expected strong effect of the stress state. Fragmentation and delamination were observed in the impact tests within the impact zone of the plates. A metallurgical study showed the crack growth to be partly intergranular, along the grain boundaries or precipitation free zones, and partly transgranular by void formation around fine and coarse intermetallic particles.