Al-Cu-Mn合金铸锭均匀化工艺及组织性能分析

采用光学金相显微镜、扫描电子显微镜及能谱分析、电导率等检测手段，对铸态和均匀化态的2219合金微观组织、第二相分布及电导率进行研究分析。结果表明，2219合金铸态组织存在着枝晶偏析，在晶界上聚集大量的Al₂Cu相，并有长条状的脆性相Al₇Cu₂（Fe、Mn）穿插在晶界上。经525 ℃均匀化处理22 h后，晶界上Al₂Cu相回溶到基体中，枝晶网络被破坏，枝晶偏析消除，Cu元素从晶界到晶内的分布趋于平稳；处于亚稳态的溶质原子从过饱和固溶体中析出，在晶内呈细小、弥散地分布，基体溶质原子固溶度降低，电子散射作用减弱，电导率提高10 %IACS。

Homogenization Process and Analysis on Microstructure and Properties of Al-Cu-Mn Alloy Ingot

The microstructure, second phase distribution and electrical conductivity of the as-cast and homogenized 2219 alloy were studied by metallographic microscope, scanning electron microscope, energy dispersive spectrum, electrical conductivity and other analytical methods. The results show that dendrite segregation exists in the microstructure of as-cast 2219 alloy. A large amount of Al₂Cu phase accumulates on the grain boundary, and long strip brittle phases A_l7Cu₂ (Fe, Mn) interpenetrate on the grain boundary.After homogenization treatment at 525 °C for 22 h, the Al₂Cu phase on the grain boundary is dissolved back into the matrix. The dendrite network is destroyed, and the dendrite segregation is eliminated. The distribution of Cu element from the grain boundary to the crystal tends to be stable. The solute atoms in metastable state precipitate from the supersaturated solid solution, and are finely and diffusely distributed in the crystal. The solid solubility of the matrix solute atoms is reduced, the electron scattering is weakened, and the conductivity is increased by 10 %IACS..