The kinetic stability of alloys having periodic minimal surface microstructures

Abstract

An alloy microstructure consisting of two domains separated by a boundary configured as a periodic minimal surface (a three-dimensional structure with zero mean curvature) was created, and its stability studied, with atomistic Monte Carlo simulation. Compared with the other domain morphologies studied, the periodic minimal surface microstructure (PMSM) was relatively stable. The instability of the PMSM began with the coalescence of two adjacent cells in the structure, after which its kinetics of domain growth were little different from those of the other microstructures. The time for this initial coalescence of cells was calculated with a statistical argument that does not include surface energy and is found to scale as r⁴ for ordering alloys, and r³ for clustering alloys, where r is a characteristic distance of the PMSM. Surfaces with low mean curvature may be favoured in nature partly for reasons of kinetics.