High strength 7000 series Al alloys are quite sensitive to intergranular corrosion (IGC) and generally a trade-off between IGC resistance and hardness exists in such Al alloys. Here, by using ultrasonic shot peening (USSP) we fabricate a gradient AA7055 whose IGC is significantly enhanced in both 57 g/L NaCl + 10 mL/L H₂O₂ solution and 3.5 wt% NaCl solution, whereas the surface hardness increases by 10%. TEM microstructure characterization and nanoscale investigation of corrosion indicate that the improvement in IGC resistance can be attributed to the disappearance of grain boundary precipitates and precipitate free zones. Surface hardening mechanism is also revealed.

中文翻译：

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超声波喷丸强化增强 7055 Al 合金的晶间耐腐蚀性


高强度 7000 系列铝合金对晶间腐蚀 （IGC） 非常敏感，通常在此类铝合金中存在 IGC 电阻和硬度之间的权衡。在这里，通过使用超声波喷丸 （USSP），我们制备了一种梯度 AA7055，其 IGC 在 57g/L NaCl + 10mL/L H₂O₂ 溶液和 3.5wt% NaCl 溶液中均显著增强，而表面硬度增加了 10%。TEM 微观结构表征和纳米级腐蚀研究表明，抗 IGC 性能的提高可归因于晶界析出物和析出物自由区的消失。还揭示了表面硬化机制。