SPINODAL DECOMPOSITION AND DISLOCATION LINES IN THIN-FILMS AND BULK MATERIALS

Phase separation of alloys around dislocation lines due to edge- and s crew-type dislocations is studied using a continuum model. The depende nce of the lattice constant, bulk modulus, and shear modulus on compos ition is shown to determine the distribution of the alloy components i n the stress fields of the dislocations. Numerical simulation results are also presented for single dislocation lines, arrays of dislocation s, and random distributions of dislocations in bulk mixtures in a cont ext relevant to quench-work-age thermomechanical treatment of alloys. The effects of dislocations on the phase separation occurring at the s urface of growing films is also discussed, showing that misfit disloca tions can create a compositionally patterned layer. The equilibrium po sition of misfit dislocations is also calculated for compositionally m odulated overlayers, and it is shown that the critical thickness for t he introduction of dislocations is reduced due to the composition modu lation.