电场均匀化对 2091Al-Li 合金的显微组织及力学性能的影响

THE EFFECT OF HOMOGENIZATION TREATMENT WITH AN ELECTRIC FIELD ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF 2091 Al Li ALLOY

应用扫描电镜（ＳＥＭ）及电子探针（ＥＰＭＡ）研究了强电场作用下Ａｌ－Ｌｉ合金的均匀化过程。实验结果表明，强电场加速了２０９１Ａｌ－Ｌｉ合金的均匀化过程，但是随着电场作用时间的增加，发生了镁、铜原子的上坡扩散，导致镁、铜原子的非平衡偏聚。因此，电场及非电场的联合处理方法是一个有效的均匀化处理制度。同时，还研究了强电场均匀化对显微组织及力学性能的影响，发现强电场均匀化促进Ｔ１相的形核，抑制δ′和Ｓ′相析出，提高了Ａｌ－Ｌｉ合金的屈强比。

The homogenization treatment with an electric field of Al Li alloy is investigated by means of scanning electron microscope(SEM) and electron probe microanalyzer(EPMA). The experimental results show that the electric field treatment promotes the homogenization process of 2091 Al Li alloy. But, increasing the duration of the electric field, it produces the upward diffusion and results in the non equilibrium segregation of Mg and Cu atoms. Therefore, the combined homogenization treatment with and without an electric field is an effective method of homogenization treatment. At the same time, the effect of homogenization treatment with an electric field on the microstructure and the mechanical properties is studied. It shows that the homogenization treatment with an electric field accelerates the nucleation of T1 precipitation phase, retards the formation of δ′ and S′ precipitation phases and improves the properties.