Investigations into Enhanced Formability of AA5083 Aluminum Alloy Sheet in Single-Point Incremental Forming

In this article, formability of aluminum alloy AA5083-sheet in single point incremental forming (SPIF) is investigated through forming limit curves (FLCs) and maximum formable wall angle considering different forming parameters and conditions. Theoretical FLCs were predicted for SPIF and conventional forming utilizing deformation instability and Marciniak-Kuczynski methods, respectively, and validated by experiments. SPIF was found to give better formability compared to the conventional one in terms of the limit strain values from varying plane strain to equi-biaxial stretching modes of deformations. Groove depth at the onset of fracture in incremental sheet forming test was observed to be more for higher forming speed, i.e., at higher tool rotational speed and feed and for lower incremental depth. The maximum formable wall angle was improved for lower step depth but not significantly increased for higher forming speed. The forming limit strains and maximum forming wall angle were found to increase for incremental forming at elevated temperature. Microstructure studies revealed grain refinement in the deformed sheet in SPIF forming, and microhardness values in the deformed sheets were observed to increase for incrementally formed parts compared to that of the as-received sheet.