Abstract:Tensile properties, fracture behavior and microstructure of Al-7.1Zn-1.1Mg-1.6Cu-0.14Zr alloy with T6 and T74 aging treatments were investigated by tensile testing, optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that, compared with the values in T6 state, the strength of the alloy in T74 state decreases by 15%; however, the elongation and electrical conductivity of the alloy in T74 state increases by 52% and 29%, respectively. The fracture mode of the alloy in T6 state is transgranular shearing and intergranular dimple mixed fracture. In T74 state, the fracture mode of alloy is transgranular dimple fracture. The fracture behavior of the alloy with different aging treatments is mainly determined by the coordinating interaction between movement of the dislocation and microstructures in the grain and grain boundary