Effect of pre-rolling temperature on microstructures, tensile properties and fracture behaviors of Al-5.9Zn-1.9Mg alloy during thermomechanical treatment

• Pre-rolling at 170 °C optimizes the balance of strength and ductility in Al-5.9Zn-1.9Mg alloy by enhancing dislocation uniformity and precipitation strengthening. • Higher pre-rolling temperature (320 °C) leads to premature precipitation during deformation, reducing the age-hardening response and final strength. • The thermomechanical treatment with pre-rolling at 170 °C yields a fracture mode combining cleavage and dimple features, indicating improved ductility. • The study provides a processing strategy to tailor the mechanical properties of Al-Zn-Mg alloys through controlled pre-deformation temperature.