Investigation of single point incremental forming parameters and forming limit curves prediction for heterostructured aluminum sheets

This study explores the formability and fracture behavior of Al-based heterostructured materials (HM) fabricated using Accumulative Roll-Bonding (ARB) and assessed through Single Point Incremental Forming (SPIF). The HM sheets, consisting of alternating AA1050 and AA7050 layers, were processed at preheating temperatures of 450 °C and 500 °C. Detailed characterization using SEM, EBSD, and TEM revealed variations in grain size, crystallographic texture, and precipitate distributions between processing temperatures, influencing the strength, hardness and ductility of HM sheets. Tensile tests showed that sheets processed at 500 °C exhibited higher elongation and improved ductility compared to those processed at 450 °C, attributed to changes in size and distribution of precipitates. Forming Limit Curves (FLC) and SPIF experiments demonstrated superior formability at 500 °C, with the HM sheets achieving higher critical wall angles and fracture strains compared to AA7050 layers alone. The results highlighted the influence of ARB to induce microstructural features, including residual stresses and shear strain localization, on the forming behavior of HM sheets. The study underscores the potential of optimizing processing conditions and material compositions to enhance the mechanical performance and manufacturability of HM aluminum sheets.