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Journal of Materials Science

, Volume 26, Issue 4, pp 940–950 | Cite as

The presence and consequences of precipitatefree zones in an aluminium-copper-lithium alloy

  • T. S. Srivatsan
  • E. J. Lavernia
Papers

Abstract

The addition of lithium to aluminium alloys has the potential for providing a class of high-strength alloys with exceptional properties suitable for aerospace applications. Potential candidates are precipitation hardenable and belong to the Al-Li-Cu family. The intrinsic microstructural features have a pronounced influence on the mechanical response of these alloys. In this work, the mechanisms responsible for the formation of precipitate-free zones along grain boundaries in precipitation-strengthened lithium-containing aluminium alloys were examined. The influence of grain morphology and the nature and type of precipitate coverage at the grain boundary in controlling the formation of these zones was analysed. The presence and influence of these zones along the grain boundaries on mechanical properties was studied for an Al-4.5Cu-1.21 Li alloy. It was found that while strength is comparable with existing high-strength alloys, the ductility decreases due to the presence of precipitate-free zones. The degradation in ductility is attributed to the particular mode of plastic deformation of this alloy, and to the restriction of plastic deformation in narrow planar zones along the grain boundaries. Fracture occurs when a critical local strain is reached in these zones. The overall consequences of precipitate-free zones along grain boundaries on mechanical properties are discussed in the light of competing effects involving the nature of matrix-strengthening precipitates, grain-boundary particles and deformation characteristics.

Keywords

Lithium Plastic Deformation Ductility Aluminium Alloy Deformation Characteristic 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Chapman and Hall Ltd 1991

Authors and Affiliations

  • T. S. Srivatsan
    • 1
  • E. J. Lavernia
    • 2
  1. 1.Department of Mechanical EngineeringThe University of AkronAkronUSA
  2. 2.Division of Materials, Department of Mechanical EngineeringUniversity of CaliforniaIrvineUSA

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