We simulate coarsening in an alloy at 50% concentration using the Ising model, under either Kawasaki (K-) or vacancy (V-) dynamics, on three different lattices (sc, fcc, bcc) at five different temperatures. At times t greater than 2000 MCS the first zero R of the spherically averaged pair correlation function obeys R˜R0+(?t)1/3 where R0, ? are constants. As the temperature falls, ?K (the value of ? for K-dynamics) falls but ?V rises, so that at low temperatures ?V»?K. The ratio ?K/?V is approximately proportional to the equilibrium concentration of minority atoms in either phase. For the various lattices, the values of ? are roughly proportional to the diffusivities and, therefore, to the squared nearest-neighbour distances, i.e., ?sc:?bcc:?fcc˜4:3:2. At T = 0.9Tc, R0 is between 2 and 3 for both types of dynamics and all three lattices; as the temperature falls, R0 remains near 2 for K-dynamics but falls, very roughly in proportion to the temperature, for V-dynamics.
|Number of pages||10|
|Journal||Physica A: Statistical Mechanics and its Applications|
|Publication status||Published - 1 May 2000|