Effects of tensile test parameters on the mechanical properties of a bimodal Al-Mg alloy

Andrew Magee, Leila Ladani, Troy D. Topping, Enrique J. Lavernia

Research output: Contribution to journalArticlepeer-review

44 Scopus citations

Abstract

The properties of aluminum alloy (AA) 5083 are shown to be significantly improved by grain size reduction through cryomilling and the incorporation of unmilled Al particles into the material, creating a bimodal grain size distribution consisting of coarse grains in a nanocrystalline matrix. To provide insight into the mechanical behavior and ultimately facilitate engineering applications, the present study reports on the effects of coarse grain ratio, anisotropy, strain rate and specimen size on the elastic-plastic behavior of bimodal AA 5083 evaluated in uniaxial tension tests using a full-factorial experiment design. To determine the governing failure mechanisms under different testing conditions, the specimens' failure surfaces were analyzed using optical and electron microscopy. The results of the tests were found to conform to Joshi's plasticity model. Significant anisotropy effects were observed, in a drastic reduction in strength and ductility, when tension was applied perpendicular (transverse) to the direction of extrusion. These specimens also exhibited a smooth, flat fracture surface morphology with a significantly different surface texture than specimens tested in the axial direction. It was found that decreasing specimen thickness and strain rate served to increase both the strength and ductility of the material. The failure surface morphology was found to differ between specimens of different thicknesses.

Original languageEnglish (US)
Pages (from-to)5838-5849
Number of pages12
JournalActa Materialia
Volume60
Issue number16
DOIs
StatePublished - Sep 2012
Externally publishedYes

Keywords

  • Aluminum
  • Bimodal grain size
  • Plastic deformation
  • Tensile testing

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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