前言 ZL205合金,是我国新研制成功的高强度铸造铝合金,已用作承力结构件代替一部分铝合金锻件。该合金在T_5和T_6两种热处理状态下使用。在光学显微镜下,这两种状态的显微组织毫无差异;然而,机械性能却有显著的不同,这主要与时效的精细结构有关。关于Al—Cu二元合金的时效强化机理,许多作者进行了综合报导;但对于复杂成份的Al—Cu系合金则研究甚少。本文主要采用室温拉伸试验和透射电子显微术相结合,来探索ZL Preface ZL205 alloy, is newly developed high strength cast aluminum alloy in China, has been used as a bearing structure instead of a part of aluminum alloy forgings. The alloy T_5 and T_6 two heat treatment using state. Under optical microscopy, there is no difference in the microstructure between the two states; however, the mechanical properties are significantly different, mainly due to the fine structure of aging. Many authors have reported comprehensively about the aging strengthening mechanism of Al-Cu binary alloys, but little is done about Al-Cu alloys with complex compositions. This paper mainly uses the combination of tensile test at room temperature and transmission electron microscopy to explore the ZL