*2.2. Forming Aluminum Alloy*

The forming behavior of aluminum alloys has been assessed through the application of different processes, which include extrusion, stretching, bending and hydroforming.

Ciuffini et al. [7] reported and discussed the relationship between the surface quality and the use of internal liquid nitrogen cooling during the aluminum extrusion. Li et al. [8] focused attention on the mechanisms of cavity nucleation and cavity growth of a 5A70 aluminum alloy during superplastic deformation. The results demonstrated a clear transition from diffusion growth to superplastic diffusion growth and plastic-controlled growth at a cavity radius larger than 1.52 and 13.90 μm. On the other hand, for the same class of aluminum alloy, Li et. al. [9] verified that the superplastic behavior depends on temperatures, strain rates, and precipitated phases during superplastic deformation. Yang et al. [10] outline the findings of the study of the effects of prebending radii on the hardness, tensile strength, yield strength, elongation and HCF performance of the 7075 aluminum alloy after creep age forming.
