  Thick-section plates made from a recently developed Al-Cu-Mg-Li alloy have
been evaluated to understand the influence of microstructure on the anisotropy
of tensile strengths after natural and artificial ageing treatment.
Pancake-shaped grains with a coarse substructure and strong crystallographic
texture with a beta-fibre orientation at the mid-thickness position are
observed. In addition, an inhomogeneous distribution of T1 precipitates through
the plate thickness has been revealed with the volume fraction of intragranular
precipitates ~ 40% higher at the plate centre than the thickness position.
Altogether these microstructural features contribute to the in-plane anisotropy
of tensile strengths that is ~ 5% higher at the mid-thickness position than the
1/4 thickness position. The variation of ageing-induced T1 precipitates through
the plate thickness further contributes to the through-thickness anisotropy
that is ~ 3% higher in T8 temper as compared to T3 temper.
