Effect of Mg content on mechanical properties and stress corrosion resistance of ZL305 aluminum alloy

ZL305 aluminum alloy is widely used in ship and marine engineering industry due to its high strength and ductility, and good corrosion resistance. As the main element in ZL305, Mg plays an important role at its mechanical and corrosion properties. This paper certifies that (1) as the Mg content increases, the casting mechanical property of ZL305 declines but the tensile strength and ductility significantly increase after T4 heat treatment process; (2) Despite these improvements, the higher Mg content is also associated with an increase in material porosity. Under the slow strain rate tensile stress corrosion condition, the intergranular fracture on the fracture surface and a proliferation of secondary intergranular cracks increase, which ultimately leads to the reduction of its stress corrosion resistance property. This study highlights the importance of modulating the Mg content in optimizing the properties of ZL305 to ensure a balance between its strength, ductility and stress corrosion resistance.