Enhanced formability in two-step forming for AA7075 sheet in -T6 and -W tempers

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Enhanced formability in two-step forming for AA7075 sheet in -T6 and -W tempers

HA Jinjin, CHOI Yumi, LEE Myoung-Gyu, KORKOLIS Yannis P.

Abstract. In response to stringent environmental regulations, the automotive industry is increasingly prioritizing lightweighting, prompting a shift towards high-strength aluminum alloys while the low formability of these alloys remain a limiting factor. This study explores a solution through a two-step forming process applied to AA7075 sheets utilizing -T6 and -W tempers. Firstly, two-step uniaxial tension experiments are performed at two prestraining levels in the -T6 temper followed by subsequent tensions in the -W. Both cases exhibit significant plastic deformation before fracture, overcoming the thinning accumulated in the first step. Additionally, a two-step hole expansion experiment is conducted under the same tempering conditions. Results are compared with single operations in each temper, evaluating force-displacement curves and thickness strain distribution around the hole. The study highlights the substantial contribution to formability enhancement, demonstrating 80% higher cup height and twice greater thinning to fracture compared to conventional single-step operations.

Keywords
Formability, Multi-Step Forming, Aa7075, Hole Expansion, Anisotropy

Published online 4/24/2024, 7 pages
Copyright © 2024 by the author(s)
Published under license by Materials Research Forum LLC., Millersville PA, USA

Citation: HA Jinjin, CHOI Yumi, LEE Myoung-Gyu, KORKOLIS Yannis P., Enhanced formability in two-step forming for AA7075 sheet in -T6 and -W tempers, Materials Research Proceedings, Vol. 41, pp 1224-1230, 2024

DOI: https://doi.org/10.21741/9781644903131-136

The article was published as article 136 of the book Material Forming

Content from this work may be used under the terms of the Creative Commons Attribution 3.0 license. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

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