强化固溶对含Sr 7085型铝合金晶间腐蚀和剥落腐蚀性能的影响

Effect of Enhanced-Solid-Solution on Intergranular Corrosion and Exfoliation Corrosion Properties of 7085 Type Aluminum Alloy Containing Strontium

采用硬度和电导率测试、晶间腐蚀和剥落腐蚀试验、金相及扫描电镜观察,研究强化固溶处理对含锶(Sr)7085型铝合金(Al-7.95Zn-1.80Mg-1.59Cu-0.15Zr-0.024Sr)硬度、电导率、晶间腐蚀和剥落腐蚀性能的影响。结果表明,与常规固溶(470℃/2 h)处理相比,强化固溶(470℃/h+480℃/2 h+490℃/2 h)处理使合金中粗大第二相溶解更为充分,经进一步常规T6(121℃/2 h)时效处理后,强化固溶处理的合金其硬度略微降低、电导率有所提高,抗晶间腐蚀和剥落腐蚀性能显著提高。本文的研究结果说明,强化固溶处理是一种提高含Sr 7085型铝合金抗腐蚀性能尤其是抗剥落腐蚀性能的有效手段。

The effect of enhanced-solid-solution treatment on the hardness, electrical conductivity, intergranular corrosion and exfoliation corrosion properties of strontium （Sr） microalloyed 7085 type aluminum alloy （ Al-7.95Zn-1.80Mg-1.59Cu-0.15Zr-0. 024Sr） was investigated by using mierohardness testing, electrical conductivity testing, intergranular/exfoliation corrosion experiments, and optical and scanning electron microscopy observation. The results show that compared with the conventional solid-solution treatment （470 （ C/ 2 h）, the enhanced-solid-solution treatment （470℃/2 h ＋ 480 ℃/2h ＋ 490 ℃/2 h） advances the dissolution of coarse second phases. After being treated by the conventional T6 （121 ℃/2 h） ageing, relative to the conventional solid-solution treated alloy, the enhanced-solid-solution alloy exhibites a slightly lower hardness, slightly higher electrical conductivity, and a considerable improvement in intergranular corrosion and exfoliation corrosion resistances. The present experimental results demonstrate that the enhanced-solid-solution treatment is an effective tool to improve the anti-corrosion, especially the anti-exfoliation corrosion properties of Sr microalloyed 7085 type aluminum alloy.