On anisotropic tensile mechanical behavior of Al-Cu-Li AA2198 alloy under different ageing conditions

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The anisotropic mechanical behavior of Al–Cu–Li (AA2198) alloy under different artificial ageing conditions as well as for different thicknesses of the material was examined in the present investigation. Material characterization was performed for three different sheet directions, namely, longitudinal (0°), diagonal (45°) and transverse (90°) to the rolling direction. The results showed that the grain structure did not have significant changes by applying different artificial ageing times. In T3 heat treatment condition, only δ′ (Al 3Li) phase was observed, while with increasing the ageing time, the major precipitates were T 1 (Al 2CuLi) phases. The latter was found to increase in size with artificial aging time. Almost similar yield strength values were observed for all investigated thicknesses, while the higher thickness specimens showed higher elongation at fracture values. Anisotropy was slightly higher at T3 condition, while the lowest anisotropy degree was noticed at the peak-aged condition. The specimens extracted in the diagonal direction showed high variation in mechanical properties, when compared with the respective results at the other two investigated directions, independently from the thickness of the specimens as well as from heat treatment condition. The smaller thickness specimens presented lower elongation at fracture values and for all investigated sheet directions, since they undergo plane stress conditions. Analysis of work hardening behavior showed that Bauschinger effect, which was not observed in T3 condition, became increasingly more prominent with artificial ageing time in all directions investigated.

Original languageEnglish
JournalJournal of Materials Research and Technology
Pages (from-to)895-908
Number of pages14
Publication statusPublished - 01.05.2023

Bibliographical note

Funding Information:
The authors would like to thank Dr. Devang Sejani from the Northwestern Polytechnical University of P.R. of China for the TEM and DSC analysis. This research has been financed by the Hellenic Foundation for Research and Innovation, under the 2nd Call for H.F.R.I. Research Projects to support Faculty Members and Researchers (Proposal ID: 03385, MIS Acronym: CorLi, Title: Corrosion susceptibility, degradation, and protection of advanced Al–Li aluminium alloys).

Publisher Copyright:
© 2023 The Authors

    Research areas

  • AA2198, Al-Li alloy, Anisotropy, Heat-treatment, Mechanical properties, Microstructure
  • Engineering