Effect on stress corrosion cracking of alloy 7075 with two-step aging

The two-step aging treatment effectively improves the stress corrosion cracking (SCC) resistance of 7075 aluminum alloy, but it will also reduce the mechanical properties of 7075 Al alloy. To simultaneously improve the tensile properties and SCC resistance of the 7075 aluminum alloy, an orthogonal test of 7075 was conducted to optimize the two-step aging parameters. The SCC behavior of the 7075 alloy was studied by scanning electron microscopy and transmission electron microscopy in a slow strain rate experiment. The results show that after heat preservation at 130℃ for 4 hours and at 170℃ for 8 hours, the alloy tensile strength, elongation and SCC index I_SSRT are 488 MPa, 10.8% and 0.095, respectively.