Effect of friction and back pressure on the formability of superplastically formed aluminium alloy sheet

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Wood, Paul and Qarni, Muhammad Jawad and Rosochowski, Andrzej (2011) Effect of friction and back pressure on the formability of superplastically formed aluminium alloy sheet. In: SheMet Conference 2011, 2011-04-17 - 2011-04-20. (https://doi.org/10.4028/www.scientific.net/KEM.473...)

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Abstract

This paper examines the effect of friction and back pressure on the formability of superplastically formed aluminium alloy AA7475 sheet at the temperature of 517 °C. Several experiments with lubrication and back pressure are performed using a simple box shape tool cavity. The coefficient of Coulomb friction between the formed sheet and tool has been determined indirectly using a finite element model to simulate superplastic forming of the box shape. Typical values determined for all lubricant conditions tested are in the range 0.1 < μ < 0.2. The void growth with strain was determined directly from measurements as a function of back pressure. The results show the application of back pressure at 1 MPa reduces the growth of voids from 7% to 0.3% void volume fraction at a logarithmic thickness strain of 0.65. This paper reports back pressure has a significantly greater role than friction in enhancing the formability of the alloy

ORCID iDs

Wood, Paul, Qarni, Muhammad Jawad ORCID logoORCID: https://orcid.org/0000-0001-7162-5524 and Rosochowski, Andrzej ORCID logoORCID: https://orcid.org/0000-0001-7896-8167;
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