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Influence of processing route on the work-hardening and ductile fracture of an AA6060 aluminium alloy

Abstract

Tensile tests on smooth and notched axisymmetric specimens were carried out to determine the large strain work-hardening curves and the ductile fracture characteristics of an AA6060 aluminium alloy for three different processing routes. The alloy was processed in three subsequent steps: 1) casting and homogenization, 2) extrusion, and 3) cold rolling and heat treatment to obtain a recrystallized grain structure. After each processing step, the material was tested after natural ageing for more than one week. A laser-based extensometer was used to continuously measure the average true strains to failure in the minimum cross-section of the specimens and the true stress-strain curves were calculated. Since these curves are influenced by necking, they do not represent the correct work-hardening of the material. Accordingly, finite element (FE) simulations of the tensile tests on the smooth axisymmetric specimens were conducted to determine the work-hardening curves to failure, using an optimization tool that interfaced with the nonlinear FE code and the experimental stress-strain curves as objectives. The microstructure of the alloy was characterized after the three processing steps by optical and scanning electron microscopy, and fractography was used to investigate the failure mechanisms.

Category

Academic article

Language

English

Author(s)

  • Odd Sture Hopperstad
  • Ida Westermann
  • Ketill Olav Pedersen
  • Trond Furu
  • Tore Børvik

Affiliation

  • Norwegian University of Science and Technology
  • SINTEF Industry / Metal Production and Processing
  • Norsk Hydro ASA

Year

2014

Published in

Materials Science Forum

ISSN

0255-5476

Publisher

Trans Tech Publications

Volume

794-796

Page(s)

284 - 289

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