Intragranular precipitation characterisation within Al-Li-Cu-Mg-Zr(-Ag) alloys.

Silver micro-additions were made to Al-Li-Cu-Mg-Zr in an effort to promote precipitation of the potent strengthening phase Ω (Al₂Cu). Within this alloy system a similar {111}_α habit precipitate T₁ (Al₂CuLi) was however also expected; it remained to be proven whether both would precipitate in Ag bearing systems and if so whether distributions of the two phases could be discriminated from each-other. Plasmon imaging provided a method to distinguish between the two phases and revealed that T¹ phase was exclusively formed in all Ag-bearing alloys. Since silver failed to promote Ω precipitation and had a detrimental influence on alloy ductility its inclusion in Al-Li-Cu-Mg-Zr systems was not recommended.