Electron Microscopic Observation on the Precipitation Sequence in Cu–Be Alloys

Electron microscopic observation on the precipitation sequence in Cu–Be alloys was carried out. Clear images of G. P. zones on {100} planes, the ordered phase, the intermediate γ′-phase, the equilibrium γ-phase and then the informations about the size, shape and distribution in each stage were obtained more clearly than before. Strains associated with precipitates in the early stages of aging and some lattice defects such as dislocations, twins and stacking faults were observed, and these mean that the precipitation in Cu–Be alloys is associated with an exclusively large strain. These electron microscopic results were discussed as compared to those obtained by other methods.