SPINODAL DECOMPOSITION IN Fe-Cr ALLOYS: EXPERIMENTAL STUDY AT THE ATOMIC LEVEL AND COMPARISON WITH COMPUTER MODELS—Ⅱ. DEVELOPMENT OF DOMAIN SIZE AND COMPOSITION AMPLITUDE

摘要

The three-dimensional interconnected microstructures resulting from spinodal decomposition in a series of thermally aged Fe-Cr alloys have been analysed in terms of scale and composition amplitude. The development of the microstructure scale was found to fit a power law with a time exponent considerably smaller than that predicted by the LSW theory but in agreement with Monte Carlo simulations of the decomposition. Numerical solutions to the classical non-linear Cahn-Hilliard-Cook equation were found to fit the classical LSW theory. A model, based on the non-linear theory of spinodal decomposition by Langer et al. is used to quantify the composition amplitude at any stage of the phase separation. A detailed comparison between the atomic scale experimental results and computer simulations of spinodal decomposition is given.