The dispersoid phase Al_(20)Cu_2Mn_3 in a 2024 Al alloy is commonly composed of twins. An observation of corresponding high resolution image shows that the twin boundary plane is a glide plane other than mirror one.

• 2024铝合金中的弥散相Al_(20)Cu_2Mn_3普遍由孪晶组成,通过高分辨像的观察分析,发现其孪晶间的界面不是镜面,而是滑移面;