Investigating formation behavior of P and Goss grains and mechanical properties of Al-Cu-Li alloy via well-designed annealing treatments

In this study, the effectiveness of annealing prior to solid solution treatment in regulating the ultimate grain structure and recrystallization behavior of spray-formed 2195 Al-Cu-Li cold-rolled plates has been elucidated. Additionally, the recrystallization activation energy was calculated through a novel equivalent conversion method, which was based on the hardness data. The results indicate that annealing at lower temperatures leads to larger ultimate grain sizes, whereas higher annealing temperatures result in grain size refinement because of the evolution of the recrystallization activation energy. The study also delved into the formation advantages of P grains and Goss grains in terms of the recrystallization behavior. P grains exhibit a nucleation advantage owing to a 40 degrees<111> orientation relationship with the deformed matrix, and the fraction of P grains accounts for above 35 % in the solutionized sample after annealing with a faster cooling rate. On the other hand, Goss grains, characterized by high-energy boundaries and greater curvature, display superior growth characteristics. In the solutionized sample annealed at 400 degrees C with a slower cooling rate, the abundant and dispersed secondary phase particles contribute to the predominance of Goss grains. Moreover, these samples exhibit enhanced elongation and strength along the transverse direction due to the greater number of preferentially activated slip systems presented in Goss grains during transverse uniaxial tension.