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Evaluation of hole expansion formability of high strength AA7075 alloy under varying temper conditions

Published

Author(s)

Dilip K. Banerjee, Kali Prasad, Abrar Salam Ebrahim, Krishnaswamy Hariharan, Uday Chakkingal

Abstract

There has been a widespread increase in the use of aluminum alloys in automotive industries for meeting ever-growing light-weighting requirements. However, edge formability is a critical manufacturing challenge that restricts their widespread use. Edge formability of sheet metal is determined using a hole expansion test (HET) and is evaluated by the hole expansion ratio (HER). The present study investigates the effect of temper conditions on the edge formability of AA7075 alloy sheets. Hole expansion tests were conducted in different temper conditions such as W-temper (super saturated solid solution followed by water quenching), under aged (UA), and peak aged (PA). Two different hole preparation techniques, punching process and drilling process, were used to prepare samples with varying edge conditions. The results demonstrate that W-temper has the highest edge formability irrespective of hole edge conditions. Researchers have reported that uniaxial stress state prevails at the hole edge during the HET. Consequently, uniaxial tensile tests were conducted on these alloy sheet specimens and various tensile properties were determined to evaluate edge formability. Furthermore, microstructural and failure analysis of the failed specimens were performed to explain the deformation behavior during HET.
Proceedings Title
IOP Conference Series: Materials Science and Engineering
Volume
1238
Conference Dates
June 6-10, 2022
Conference Location
Lorient, FR
Conference Title
41ST INTERNATIONAL DEEP DRAWING RESEARCH GROUP CONFERENCE

Keywords

Stretch-flangeability, Hole expansion, Aluminium AA7075 alloy, Formability, Heat treatment

Citation

Banerjee, D. , Prasad, K. , Ebrahim, A. , Hariharan, K. and Chakkingal, U. (2022), Evaluation of hole expansion formability of high strength AA7075 alloy under varying temper conditions, IOP Conference Series: Materials Science and Engineering, Lorient, FR, [online], https://doi.org/10.1088/1757-899X/1238/1/012038, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934155 (Accessed April 22, 2024)
Created May 31, 2022, Updated November 29, 2022