Journal of Materials Science

, Volume 21, Issue 5, pp 1553–1560

Microstructural characterization of two lithium-containing aluminium alloys

Authors

  • T. S. Srivatsan
    • Georgia Institute of Technology
  • E. J. CoyneJr
    • Lockhead-Georgia Company
  • E. A. StarkeJr
    • University of Virginia
Papers

DOI: 10.1007/BF01114708

Cite this article as:
Srivatsan, T.S., Coyne, E.J. & Starke, E.A. J Mater Sci (1986) 21: 1553. doi:10.1007/BF01114708

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.

Copyright information

© Chapman and Hall Ltd. 1986