EFFECT OF NONLINEARITY OF THE EVOLUTION EQUATION ON THE SPINODAL DECOMPOSITION PROCESS IN ALLOYS

The spinodal decomposition process is usually described by nonlinear e volution equations. One of them is the Langer-Bar-on-Miller (LBM) theo ry that describes the time evolution df a double-Gaussian probability distribution function of composition. In the present study, LBM theory was modified in terms of composition dependence of mobility. The refo rmulated analytical expression was quantitatively applied to the reali stic structure change. In fact we investigated the nonlinear effect on phase decomposition using computer simulations based on the present m odified LBM theory and compared the result with the original LBM theor y. It was made clear that the additional nonlinear terms played a domi nant role in the phase decomposition process. Especially, when the pro bability distribution function becomes broader in the early stage, the new nonlinear terms contribute to the rapid phase decomposition. [S01 63-1829(98)09041-9].