Pre-hardened forming process for heat-treatable aluminum alloy at room temperature

• A novel pre-hardening cold forming (PHCF) eliminates the post-forming heat treatment. • The excellent formability at room temperature arises from the formed kink bands. • The coexistence of GPII zones and η′ in cap beam component contribute to T6 strength. • The yield strength of pH alloys with different deformation exhibits convergence after PB. The manufacturing process of high-strength aluminum alloys, which involves forming followed by heat treatment, is inefficient and costly, limiting their application in industries such as aviation, aerospace, and automotive. Therefore, this paper proposes a pre-hardened cold forming process (PHCF), where the pre-hardened AA7075 blanks exhibit superior strength and comparable formability compared to W alloy. The mechanical properties of different sections of the formed cap beam component after paint baking show good uniformity, all meeting the standards of T6-temper alloy. The observed enhancement in strength and ductility for PH alloys is attributed to: on the one hand, the formation and propagation of kink bands stabilize the inhomogeneous plastic deformation of pH alloys; and on the other hand, the coexistence of GPII zones and η′ precipitates in the paint-baked cap beam component, along with the mixed interaction mechanisms of dislocation cutting and bypassing, contribute to mechanical properties comparable to T6-temper alloy. The PHCF process eliminates the need for post-forming heat treatment, allowing for the production of high-strength components, greatly improving production efficiency, and promoting the further application of high-strength aluminum alloys.