Effect of age condition on fatigue properties of 2E12 aluminum alloy

Abstract

The fatigue behaviors of 2E12 aluminum alloy in T3 and T6 conditions at room temperature in air were investigated. The microstructures and fatigue fracture surfaces of the alloy were examined by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The results show that the alloy exhibits higher fatigue crack propagation (FCP) resistance in T3 condition than in T6 condition, the fatigue life is increased by 54% and the fatigue crack growth rate (FCGR) decreases significantly. The fatigue fractures of the alloy in T3 and T6 conditions are transgranular. But in T3 condition, secondary cracks occur and fatigue striations are not clear. In T6 condition, ductile fatigue striations are observed. The effect of aging conditions on fatigue behaviors is explained in terms of the slip planarity of dislocations and the cyclic slip reversibility.

Keywords

2E12 aluminum alloy / aging / fatigue life / fatigue crack growth rate / fatigue fracture