Warm Forming of AA7075‐T6 with Direct Electrical Resistance Heating

Abstract

High-strength aluminum alloy sheet materials are of interest to automobile manufacturers for components that can significantly reduce vehicle mass. But, the practical application of these materials is limited by low formability. Warm forming offers a potential means to overcome this limitation. The warm-forming behavior of an AA7075-T6 sheet material is investigated using direct electrical resistance to rapidly heat material for tensile testing. These experiments probe the potential to use rapid heating from the hardened T6 condition to form under retrogression conditions that provide ductilities significantly better than those possible at room temperature. The key advantage of this approach is the possibility to recover nearly full strength by reaging after warm forming, which may be possible through the paint-bake cycle alone. The development, implementation, and validation of the direct electrical resistance heating tensile testing system are discussed. The results of tension tests and retrogression-reaging experiments are presented.