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应用透射电镜研究了2091 Al-Li 合金T_6,T_8不同时效处理后的显微组织,并讨论了不同组织对性能的影响。指出在两种处理中δ′相和晶界无析出区(PFZ)的长大均与时效时间的1/3次方成正比,而预应变加速了它们的生长。另外预应变促使 S′、T_1相形核,使其均匀细小地分布在 Al基体和晶界附近δ′的无析出区中,从而使合金在较短时间达到更高的强度峰值。在 T_648小时处理的合金中观察到 T_2相,通过衍射,高分辨象确定为五次对称准晶相。
The microstructure of 2091 Al-Li alloy T_6 and T_8 under different aging treatments was studied by transmission electron microscope. The effects of different tissues on the properties were also discussed. It is pointed out that the growth of δ ’phase and PFZ in both treatments is proportional to 1/3 of the aging time, while the pre-strain accelerates their growth. In addition, the pre-strain causes the nucleation of S ’and T_1 phase, which distributes uniformly and finely in the Al matrix and the non-precipitation region of δ’ near the grain boundary, so that the alloy reaches a higher intensity peak in a shorter time. The T_2 phase was observed in T_648h alloy and was identified as quintic quasicrystal by diffraction and high resolution.