Abstract: The structures of Al20Cu2Mn8 (T phase) which precipated out during homogeneous sequence in 2024 high strength Al alloys have been studied using covergent been electron diffraction (CBD) , selected area electron diffraction (SAD) and x-ray energy dispersive spectrometer (EDS). The space group of T phase has been determined to be Bbmm ,and the lattice parameters of T phase have a=2.41nm, b=1.25nm, c=0.78nm. T phase takes the shape of rod which axis along[010] direction of itself.

Key words: 会聚束衍射, 铝合金, 弥散金, 微观结构