The effect of alloying additions (Ni, Fe, Cr, Ta, Mo, V, Ti, Si) on the misfit of developmental Co-Al-W alloys will be examined using Polaris. The Co3(Al,W) precipitate phase (55% volume fraction) misfit is a key parameter to minmise in order to maximise the creep resistance of these alloys and this will be characterised at both room temperature and operation temperatures up to 1100 K. A high misfit alloy will then be held at temperature and the release of misfit during aging examined, which is a dislocation-mediated process that will be accompanied by a change in peak width. Good resolution is required in order to separate the fcc peaks from the two phases, which differ in lattice parameter by less than 0.5%. Neutrons are required in order to observe the superlattice peaks and hence subtract these from the fcc peaks for the precipitate phase.