Aluminum Alloy 7A09 Pre-stretched Plate Double-grade Over-aging User Aviation Of Research

This paper takes aluminum alloy 7A09 used in middle-wing fore-spar edge of agriculture aircraft JL8 as the research object, emphasizes the research on double-grade over-aging heat-treatment process after solution treatment. Through explore research on double-grade over-aging process and application test of section profile 7A09, grasp differences of structures and properties of section profile 7A09 between double-grade over-aging state and T6 single-grade artificial aging state.Section profile 7A09 has good properties after double-grade over-aging heat-treatment, whose notch sensitivity-resistance, stress corrosion-resistance life (conductivity) and peel corrosion-resistance properties are better than those after T6 single-grade artifice aging, low frequency fatigue property is as much as that after T6 single-grade artificial aging, and stress corrosion-resistance property is improved on the premise of strength meeting to the design requirement.Heat-treatment process of aluminum alloy 7A09 is that: firstly solution treating, then single-grade artificial aging (T6) or double-grade over-aging. Aluminum alloy 7A09 can obtain a supersaturated sosoloid after solution treatment, during the later aging, the separated subsequence of precipitate phase is: a supersaturated sosoloid→G.P. area→η'→η(MgZn₂)→T(Al₂Mg₃Zn₃).