Local Thermomechanical Processing for Improving Formability of High Strength Aluminum Sheets

Conference · Tue Mar 29 04:00:00 EDT 2022

DOI:https://doi.org/10.4271/2022-01-0244· OSTI ID:1864755

Nasim, Wahaz ^[1]; Das, Hrishikesh ^[1]; Kulkarni, Shank S. ^[1]; Rohatgi, Aashish ^[1]; Herling, Darrell R. ^[1]; Grant, Glenn J. ^[1]; Upadhyay, Piyush ^[1]; Efe, Mert ^[1]

---

1. BATTELLE (PACIFIC NW LAB)

Limited room temperature formability hinders the wide-spread use of high strength aluminum alloys in structural body-in-white parts. Stamping or extrusion at warm temperatures or from softer tempers are the current solutions. In this work, our approach is to start with age-hardened sheets from 7xxx and 6xxx family of alloys and improve their formability using local thermomechanical processing only in the regions demanding highest ductility in the forming processes. We achieved local formability improvements with friction stir processing and introduce another process named roller-bending as a concept and showed its feasibility through finite element simulations. Initial results from FSP indicated significant deformation in the processed zones with minimal sheet distortion. FSP also resulted in dynamically recrystallized, fine grained (d < 5 µm) microstructures in the processed regions with textures significantly different from the base material. This resulted in formability improvements of > 30% in 7085-T76 and > 50% in 6111-T6 alloys as measured by minimum bend radius (r/t) ratios established with V-bending tests performed at 90° and 180° bend angles. Based on the encouraging initial results, we envision applicability of these processes in both pre- and post-stamping stages through integration of the process tools as end-effectors to robotic arms.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1864755
• Report Number(s): PNNL-SA-168320
• Country of Publication: United States
• Language: English