  We apply a combinatorial approach to study the influence of Mg concentration
on the precipitation kinetics in an Al-Cu-Li alloy using a diffusion couple
made by linear friction welding. The precipitation kinetics is monitored in the
composition gradient material using simultaneous space and time-resolved
in-situ small-angle X-ray scattering measurements during ageing, and the
strengthening of the precipitates is evaluated by micro-hardness profiles. This
data provides an evaluation of the amount of Mg necessary to promote
precipitation of the T1-Al2CuLi phase.
