Journal of Materials Science

, Volume 21, Issue 5, pp 1553–1560

Microstructural characterization of two lithium-containing aluminium alloys

  • T. S. Srivatsan
  • E. J. CoyneJr
  • E. A. StarkeJr
Papers

Abstract

The microstructures of two lithium-containing aluminium alloys have been investigated. The two alloys were an Al-Li-Mn alloy, heat treated to provide an under-aged, peak-aged and an over-aged condition, and a commercial Al-Cu-Li alloy, 2020, heat treated and aged to contain ordered precipitate structures. It was observed that both materials were recrystallized with fairly large grains. The Al-Li-Mn material had a high volume fraction of Al6Mn dispersoids and the Al-Cu-Li alloy had a substantial volume fraction of coarse intermetallic particles and intermediate size disperoids. The major strengthening precipitates were identified from brightfield and dark-field images and selected-area diffraction patterns taken in the transmission electron microscope. Precipitate-free zones were found to be present in both the Al-Li-Mn and Al-Cu-Li alloys. The results of this study suggest that the peak-aged Al-Cu-Li alloy and the under-aged and peak-aged Al-Li-Mn alloys enhance deformation to occur primarily by planar slip, and the larger particle size and interparticle spacing of the over-aged Al-Li-Mn promotes a combination of planar slip and Orowan looping.

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Copyright information

© Chapman and Hall Ltd. 1986

Authors and Affiliations

  • T. S. Srivatsan
    • 1
  • E. J. CoyneJr
    • 2
  • E. A. StarkeJr
    • 3
  1. 1.Georgia Institute of TechnologyAltlantaUSA
  2. 2.Lockhead-Georgia CompanyMariettaUSA
  3. 3.University of VirginiaCharlottesvilleUSA

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