时效处理对2124铝合金预拉伸厚板微观组织与腐蚀行为的影响

Influence of Aging Treatment on Microstructure and Corrosion Behavior of 2124 Aluminum Alloy Pre-Stretching Plate

采用透射电镜、晶间腐蚀、剥落腐蚀实验和极化曲线测试等手段,研究经不同温度和时间时效处理后的2124铝合金预拉伸厚板的微观组织演变,并分析时效处理对合金腐蚀性能的影响。结果表明,随着时效温度的升高或时效时间的延长,合金晶内析出相由S'相向S相转变,析出相数量相逐渐增多,尺寸增大,合金晶界析出相呈链状分布且发生粗化,晶界附近出现无沉淀析出带并宽化;合金抗晶间腐蚀和剥落腐蚀能力减弱,腐蚀敏感性提高,合金的腐蚀倾向增大,腐蚀速率也呈增大的趋势。在时效过程中S'析出相、晶界析出相和无沉淀析出带的变化是影响合金预拉伸厚板腐蚀行为的主因。

The microstructures and corrosion properties of 2124 aluminum alloy pre-stretching plates after aging were investigated using transmission electron microscopy （TEM） , intergranular corrosion, exfoliation corrosion and polarization curve tests. The influence of aging treatment on corrosion resistances was analyzed. The results show that, with the increase of aging temperature or aging time, inte- rior precipitates chang from S＇ phase to S phase. The amount and size of precipitates both increase. After aging at high temperature or for long time, the grain boundary precipitates present chain distribution and become coarser. Moreover, wide precipitate-free zones ap- pear near the grain boundary. Intergranular and exfoliation corrosion resistances decrease and corrosion sensitivity increases with the in- crease of aging temperature or aging time. With the increase of aging temperature or aging time, alloy is susceptible to corrosion, and its corrosion rate also increases. The effect of aging treatment on corrosion sensitivity is closely related to S＇ phase, the phase precipita- ted in grain boundary and precipitate-free zone.