ABSTRACT

Specimens of AA2099-T8 were immersed for different times ranging from 2 to 180 min in 0.1M NaCl. The development of corrosion around intermetallic particles was studied by scanning electron microscopy (SEM) with energy-dispersive X-ray spectrometry (EDXS). The degradation evolution of each major intermetallic particle after exposure of the alloy to electrolyte allowed to determine which particle corroded during the first stages of immersion. The corrosion of lithium-containing particles was also investigated by transmission electron microscopy (TEM). The earliest stages of attack started with localised corrosion of Al₂CuMg (S-phase) particles resulting in dealloying which was followed by trenching around these particles. After 10 min, trenching was observed around Al₇Cu₂Fe(Mn) particles and then progressed to AlCuFeMnSi particles after 90 min.

摘要

AA2099-T8 的样品在 0.1M NaCl 中浸泡 2 到 180 分钟的不同时间。通过扫描电子显微镜 (SEM) 和能量色散 X 射线光谱法 (EDXS) 研究金属间化合物颗粒周围腐蚀的发展。合金暴露于电解质后每个主要金属间化合物颗粒的降解演变允许确定哪个颗粒在浸泡的第一阶段被腐蚀。还通过透射电子显微镜（TEM）研究了含锂颗粒的腐蚀。腐蚀的最早阶段开始于 Al ₂ CuMg（S 相）颗粒的局部腐蚀，导致脱合金，随后在这些颗粒周围形成沟槽。10 分钟后，在 Al ₇ Cu ₂周围观察到沟槽Fe(Mn) 颗粒，然后在 90 分钟后发展为 AlCuFeMnSi 颗粒。