Monte Carlo Investigation of Thermal Stability and Morphology Development of Coherent Multilayers at Elevated Temperatures

摘要

The thermal stability of nanoscale A/B multilayers with fcc lattice structure has been investigated by means of Monte Carlo (MC) simulations based on a vacancy migration algorithm Starting from a single crystal layer stack with different A- and B-layer thicknesses and ideally planar A/B interfaces, the simulations revealed that the thermally induced decomposition of individual layers starts by localized breakthroughs of say component A through the thinner B layers. Due to the lateral extension of breakthroughs, every B layer evolves to a fiber-like network of phase B embedded in phase A which transforms to a disperse morphology in a later stage. Rough estimates which permit to relate the time scale of the simulations to experimental studies, are given for the Co-Cu system. To characterize the layer stability, the time up to the appearance of the first break-through has been analyzed as a function of the thickness of (111)- and (110)-oriented layers.