Isothermal γ precipitation in a β Cu–Zn–Al alloy

The isothermal decomposition of the β phase in a Cu–18.52Zn–14.74Al (at.%) alloy was investigated. On ageing the alloy in the temperature range of 473 to 773 K, the β phase was found to decompose by the precipitation of γ and α phases. The growth rate of the γ phase precipitates shows that the involved process is a classical diffusion-limited. During their growth, the precipitates show evidence of morphological splitting. By considering the elastic energies of various precipitates shapes, an effective size for splitting is predicted.