Effect of Homogenization and Zn/Mg Ratio on the Mechanical Properties, Stress Corrosion Cracking Resistance, and Quench Sensitivity of Al–Zn–Mg–2.5Cu (AA7095) Alloys

Abstract

This study examines the effect of homogenization and Zn/Mg ratio on the mechanical properties, stress corrosion cracking resistance, and quench sensitivity of Al–Zn–Mg–2.5Cu (AA7095) alloys. The alloys are processed using one-stage and two-stage homogenization followed by high-temperature solution treatment and T6 aging. Mechanical properties, including hardness, tensile strength, and ductility, are evaluated. Quench sensitivity is assessed by measuring the loss of hardness at varying distances from the water-quenched end. The results indicate that alloy B (5.4) exhibits the highest quench sensitivity due to higher precipitation kinetics. Additionally, the study reveals that the alloy with a higher Zn/Mg ratio (5.4) displays better precipitation strengthening but shows a more significant loss in hardness during quenching. SCC resistance is evaluated in both air and NaCl solution environments, showing that the alloy with a lower Zn/Mg ratio demonstrated better SCC resistance. These findings provide insights into optimizing the mechanical properties and resistance to SCC of AA7095 alloys through homogenization and Zn/Mg ratio control.