Abstract
The kinetics of spinodal decomposition and morphological evolution near a crystalline surface (an edge in two dimensions) were investigated by microscopic master equations in both the point and pair approximations and a second-neighbor interaction model in a two-dimensional model system. It is shown that, in the presence of a surface, spinodal decomposition initially involves surface segregation, followed by anisotropic decomposition in the near-surface region, with subsequent isotropic decomposition in the bulk. It is demonstrated that, due to segregation, a surface spinodal decomposition may take place for alloys whose overall average compositions are outside the bulk spinodal. It is found that the presence of a surface results in a dominant concentration wave, which produces interesting transient morphological patterns such as distorted hexagonal precipitate lattices for relatively low-volume fractions and straight stripes at high-volume fractions in the near-surface region. The effect of pair correlations on the kinetics of spinodal decomposition and morphologies was studied.
Original language | English (US) |
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Pages (from-to) | 229-240 |
Number of pages | 12 |
Journal | Surface Science |
Volume | 355 |
Issue number | 1-3 |
DOIs | |
State | Published - Jun 1 1996 |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Surfaces and Interfaces
- Surfaces, Coatings and Films
- Materials Chemistry