X-RAY-SCATTERING STUDY OF EARLY-STAGE SPINODAL DECOMPOSITION IN AL0.62ZN0.38

In situ small-angle x-ray scattering studies of the spinodal decomposi tion kinetics in an AlZn alloy at the critical composition have been p erformed with a time resolution of 10 ms. The kinetics of fluctuation relaxation above the critical point merges smoothly with the early-sta ge kinetics of fluctuation growth below T-c. Strong nonlinearities are present at the earliest times measured, even above the critical point . The nonlinear theory of Langer, Bar-on, and Miller [Phys. Rev. A 11, 1417 (1975)] quantitatively fits the data with reasonable thermodynam ic and transport parameters.