Properties of a Retrogressed and Re-Aged 7075 Aluminum Alloy

摘要

Retrogression and Re-aging (RRA) is a new thermal process introduced for the purpose of enhancing corrosion resistance of 7075-T651 aluminum alloy while maintaining its T6 strength. In this study a 7075 material so treated was investigated for its mechanical and corrosion resistant properties. Results indicated that the RRA treated 7075 was significantly better than the T6 temper in resistance to stress corrosion cracking and exfoliation corrosion. The loss in strength from RRA treatment was minimal. Electron microscopy of the fractured surface showed a distinct difference in the fracture mode when compared to the T6 temper condition. Tests results indicated that the RRA heat treatment resulted in fatigue and fracture toughness properties superior to the 7075-T651.