Effect of Initial Microstructures on Planar Tensile Anisotropy and Fatigue Crack Growth of Creep Age Formed 2050 Al–Li Alloy.

This work investigates the influence of initial microstructure characteristics on the creep age forming behavior, mechanical anisotropy and fatigue crack growth resistance of creep age formed components. Components made by 2050 Al–Li alloy with fine, coarse and fibrous grain structures were prepared. The results indicate that the components with fibrous grains significantly increases the creep strain, which were generated by large-strain pre-deformation. Additionally, these components exhibit the highest yield and ultimate tensile strengths. On the other hand, components with coarse grains demonstrate superior fatigue crack growth resistance compared to other microstructures. Conversely, components with fine grains exhibit the lowest in-plane anisotropy value. The fatigue crack growth resistance of the three microstructures follows a descending order of coarse grains, fine grains, and fibrous grains. For applications requiring less anisotropy, the AA2050 alloy with fine grains is recommended. Conversely, the alloy with coarse grains is suitable for components subjected to cyclic loading. Lastly, the alloy with fibrous grains is ideal for structural components due to its high ultimate tensile strength and creep strain. [ABSTRACT FROM AUTHOR]