“…During the past ten years, an increasing number of experiments have been performed on single crystals in order to highlight this anisotropic effect (see e.g. Guilarducci et al, 1987;Sato et al, 1988;Fratzl et al, 1993;Lyon & Simon, 1994, hereinafter referred to as paper I; Pedersen et al, 1997). However, very few experiments have been attempted to determine the associated displacements: in the case of the plate-like Guinier±Preston (GP) zones formed in an Al±Cu alloy, Matsubara & Cohen (1983) have measured its large-angle scattering, i.e.…”