Manufacturing large 2219 Al-Cu alloy rings by a cold rolling process

Transition rings made of 2219 Al-Cu alloy for tanks with diameters exceeding 5 m require enhanced performance. However, a coarse-grained structure and residual Al2Cu particles deteriorate the mechanical properties of large 2219 Al-Cu alloy rings. A cold rolling (0-6%) process was performed before solution treatment to improve the mechanical properties of such rings. The results showed that increasing the cold rolling deformation led to a higher dislocation density, yielding finer recrystallized grains after heat treatment; moreover, finer grains led to deeper and longer intergranular cracks, thereby increasing the elongation. Increasing the cold rolling deformation also facilitated the fragmentation of Al2Cu particles and enhanced the degree of supersaturation after solution heat treatment, which increased the driving force required for aging precipitation; the yield strength first increased (0-4%) and then decreased (4-6%) with respect to the variation in the characteristics of the precipitated phases. The radial tensile sample that was 6% cold-rolled may experience brittle fracture, which may lead to a significant decrease in the mean tensile strength and elongation. Overall, using the cold rolling process is feasible, and the 4% cold-rolled sample exhibited the best mechanical properties.