Coarsening dynamics in elastically anisotropic alloys

We study in situ the coarsening dynamics in elastically anisotropic phase-separating alloys, taking advantage of coherent x rays. Temporally fluctuating speckle intensities are analyzed for two different Ni-Al-Mo samples with different lattice misfits between precipitates and matrix. The detected long-term correlations depend not only on the norm but strongly on the direction of the scattering vector-an unambiguous proof of direction-dependent coarsening dynamics. For strong lattice misfits, our results indicate coalescence of precipitates in the {100} planes.