The mechanical properties of large 2219 Al–Cu alloy rings need to be further improved with the diameter of the launch vehicle being more than 10 m. In this study, the effects of cold rolling (CR) and cold compression on microstructure evolution and the comprehensive mechanical properties of such rings were compared. The evolution of dislocation characteristics, grain structure, second phase, and the mechanical properties of the T8-aged samples were examined. Results show that compared with CR, because of deformation characteristics, cold compression deformation induces less increase in dislocation densities; however, the increase in dislocation densities on the core was higher than at other positions, resulting in a more uniform grain structure and elongation in the axial and radial direction. The cold compression deformation contributes to the uniform dissolution of the secondary phase, resulting in denser precipitates, and thus improved strength. Brittle fractures occur in fewer CR samples because of the longer moving distance of the Al matrix. In summary, both CR and cold compression can improve the mechanical properties. However, the cold-compressed sample exhibits more uniform microstructure and higher comprehensive mechanical properties (the radial elongation increased from 7.1 to 11.2%; the in-plane anisotropy decreased from 36.6 to 8.9%), without any brittle fractures, because of more uniform metal flow.

中文翻译：

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冷变形方式对2219 Al-Cu合金大环显微组织均匀性和力学性能的影响

随着运载火箭直径超过10 m，大型2219 Al-Cu合金环的力学性能有待进一步提高。在本研究中，比较了冷轧（CR）和冷压缩对此类环的微观组织演变和综合力学性能的影响。检查了 T8 时效样品的位错特征、晶粒结构、第二相和机械性能的演变。结果表明，与冷轧相比，由于变形特性，冷压缩变形引起的位错密度增加较小；然而，核心上位错密度的增加高于其他位置，导致晶粒结构更加均匀，轴向和径向的伸长率也更高。冷压缩变形有助于第二相的均匀溶解，产生更致密的析出物，从而提高强度。由于铝基体的移动距离较长，脆性断裂发生在较少的 CR 样品中。综上所述，冷压和冷压均可提高力学性能。然而，冷压缩样品表现出更均匀的微观结构和更高的综合力学性能（径向伸长率从7.1％增加到11.2％；面内各向异性从36.6％下降到8.9％），并且由于金属更加均匀，没有任何脆性断裂。流动。