Characterization of Material Behavior and Constitutive Modelling of Aerospace Aluminum Alloy Sheets for Hot Blank-Cold Die (HB-CD) Forming

High strength aluminium alloy sheets, mainly 7xxx and some 5xxx, have been used in many aerospace applications for their lightweighting potentials over conventional materials. To overcome their limited formability at ambient temperatures, especially for components with intricate details, superplastic forming has been used to deform these aluminium alloys at high temperatures and extremely slow rates. With cost and energy efficiency becoming more pressing issues, even for the cost and production rate insensitive aerospace sector, alternative sustainable forming techniques are needed. Recently, hot blank – cold die (HB-CD) forming, a non-isothermal sheet forming approach, has been recently introduced as a means to achieve high sheet formability at reduced energy consumption and high production rates to meet the needs of the automotive sector. In this work, we explore the possibilities of utilizing HB-CD for forming aerospace-quality aluminium alloys. The study focuses on exploring the tensile deformation behavior of AA5083 and AA7075 sheets at a wide range of experimental conditions (Temperature: 25℃ ~ 450℃, Strain rate: ~) and the corresponding changes in the deformation mechanisms to identify the appropriate range for HB-CD forming. The development of a constitutive model that can capture isothermal material behavior, and used to predict the non-isothermal sheet behavior in HB-CD, is also presented.