High resolution study of one‐dimensional long period superstructures in Cu₃Sn with additions of zinc and nickel

High resolution electron microscopy and electron diffraction are applied to the study of the long period superstructure of alloys with nominal composition Cu₃Sn. The apparently conflicting results in the literature can be reconciled since a variety of long spacings occur depending on the exact composition and on the impurity contents. The structures consist in all cases in a number n of unit cells of the Cu₃Ti structure (a superstructure of h.c.p.) followed by n cells (represented by n̄) displaced over a vector R = 1/2 [100]. The following long period structures are observed: 55, 44, 33, and 22. The addition of Zn markedly decreases n, whereas the effect of a Ni addition causes the same effect but in a less striking manner.