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

Paul Wood, Muhammad Jawad Qarni, Andrzej Rosochowski

Research output: Contribution to conferencePaperpeer-review

6 Citations (Scopus)
347 Downloads (Pure)

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
Original languageEnglish
Pages532-539
Number of pages8
DOIs
Publication statusPublished - 28 Mar 2011
EventSheMet Conference 2011 - Leuven, Belgium
Duration: 17 Apr 201120 Apr 2011

Conference

ConferenceSheMet Conference 2011
Country/TerritoryBelgium
CityLeuven
Period17/04/1120/04/11

Keywords

  • aluminium alloy AA7475,
  • superplastic forming
  • lubrication,
  • friction coefficient
  • back pressure
  • finite element analysis
  • FEA

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