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高强铝合金应力腐蚀破裂是宇航工业多年来存在的一个问题。大多数破裂发生在7079、7075和2014锻件的T6状态,最敏感的材料是7079-T6模锻件。破裂发生在机加工的零件上,诸如翼梁、起落架作动筒、隔框,加工中的配件以及受力构件(图1)。破裂一般发生于短横向晶粒—平行锻件分模面或在锻件的分模面上。通常锻件是在T 6状态下完成机加工的。机加工后,残余张应力立刻暴露出来,受压缩应力的金属表面发生严重翘曲。固滚热处理后水中淬火产生了内应力梯度。
Stress corrosion cracking of high-strength aluminum alloy is a problem existing in the aerospace industry for many years. Most fractures occurred in the T6 state of the 7079, 7075 and 2014 forgings, the most sensitive material being the 7079-T6 forgings. Cracking occurs on machined parts such as spars, landing gear jackets, bulkheads, machined fittings, and stressed components (Figure 1). Rupture usually occurs in the short transverse grain-parallel parting surface or on the parting surface of the forging. Forgings are usually machined in the T 6 state. After machining, the residual tensile stress is exposed immediately, and the metal surface under compressive stress undergoes severe warpage. After solid heat treatment, quenching in water produced an internal stress gradient.