摘要
通过浸泡实验、析氢实验、SEM和极化曲线测试研究在170°C下不同时效时间对锻造AZ80镁合金腐蚀性能的影响。结果表明:在时效初期阶段,锻造AZ80镁合金腐蚀速率随着时效时间的延长而急剧降低,而时效时间超过20 h后腐蚀速率又缓慢上升。当时效时间小于20 h时,β-Mg17Al12含量随时效时间的延长不断增加,锻造AZ80镁合金腐蚀速率降低;时效39 h后,β相长大,基体中铝含量降低,导致随着时效时间的延长合金腐蚀速率上升。当β-Mg17Al12相含量较低时,试样容易产生点蚀,试样表面呈多孔蜂窝状;反之,当β-Mg17Al12相含量较高时,试样腐蚀较均匀。
The corrosion behaviors of an as-forged AZ80 magnesium alloy after aging treatment for various durations at 170 °C were investigated by immersion test, H2 evolution test, SEM and potentiodynamic polarization curve measurement. The results show that the corrosion rate of the alloy decreases dramatically with the increase of aging time during the initial aging stage, but increases slowly with the aging time longer than 20 h. The volume fraction of β-Mg17Al12 increases with aging time within the first 20 h, leading to the decrease of corrosion rate. After aging for longer than 39 h, the growth of β phase is accompanied by the consumption of aluminum in the matrix, resulting in an increase in the corrosion rate. When the volume fraction of ？ phase is low, specimens suffer from severe local corrosion, which results in a porous surface. On the contrary, when the volume fraction of ？ phase is high, specimens suffer uniform corrosion attack.
关键词
AZ80镁合金
时效处理
腐蚀
AZ80 magnesium alloy
aging treatment
corrosion
