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为了深刻理解AA2024-T3铝合金暴露在含氯水介质中金属间化合物相的响应方式,运用扫描电镜获得腐蚀试验前后合金表面的形貌信息,进行能谱分析确定金属间化合物粒子的成分变化,使用原子力显微镜检测金属间化合物相电化学反应所引起的高度变化,并对去合金金化的Al_2CuMg粒子及其周边区域进行透射电镜分析。研究发现,去合金化Al_2CuMg粒子为由5~20 nm大小的体心立方铜粒子组成的多孔多晶体结构;在去合金化早期,铝基体就开始在Al_2CuMg粒子周边出现沟槽状腐蚀;Al-Cu-Fe-Mn-(Si)粒子周边沟槽状腐蚀的发展不均匀且比Al_2CuMg去合金化需要更长时间萌生;由Al_2CuMg和Al_2Cu组成的粒子簇的局部腐蚀主要与Al_2CuMg粒子相关。
In order to deeply understand the response of AA2024-T3 aluminum alloy exposure to chloride-containing aqueous medium, the morphology of the alloy surface before and after the corrosion test was obtained by scanning electron microscope, and the composition of the intermetallic compound particles was analyzed by energy spectrum analysis. Atomic force microscope (AFM) was used to detect the height change caused by the electrochemical reaction of the intermetallic compound phase. Transmission electron microscopy analysis was performed on the alloying Al 2 CuMg particles and their surrounding areas. The results show that the de-alloying Al 2 CuMg particles are porous polycrystalline structure composed of body-centered cubic copper particles with the size of 5-20 nm. At the early stage of de-alloying, the Al matrix begins to appear groove corrosion in the periphery of Al 2 CuMg particles. The development of trench-like corrosion around Cu-Fe-Mn- (Si) particles is not uniform and takes longer time to de-alloy than that of Al 2 CuMg. The local corrosion of particle clusters composed of Al 2 CuMg and Al 2 Cu mainly correlates with Al 2 CuMg particles.