Early stages of spinodal decomposition in an aluminum-zinc alloy

A small-angle X-ray scattering study has been made of isothermal decomposition in an Al-Zn alloy containing 22 at.% Zn. The changes in the X-ray spectra in the early stages of the decomposition at 65°C were in accord with the theory of spinodal decomposition proposed by J.W. Cahn. [Acta Met. 9, 795 (1961).] The diffusion coefficient derived from the kinetics agreed with an extrapolation of high-temperature data and the measured value of the gradient-energy coefficient was (16 ± 3) × 10-6 erg cm-1