Topological Effects in Coarsening of Grain-Boundary-Engineered Microstructures

In FCC metals such as copper, grain boundary character distributions can be engineered by a technique known as grain boundary engineering. By increasing the special boundary (mainly low S boundaries) content in the network, this method is known to significantly reduce the grain growth rate at elevated temperatures, which makes grain-boundary-engineered materials attractive for potential applications under irradiation conditions. Here we applied phase-field simulations to studying the quantitative relation between grain-boundary-engineered microstructures and their coarsening kinetics. It was found that the special boundary population alone is not sufficient to determine the evolution of the grain boundary network. Microstructures with the same special boundary population but different topologies can exhibit different coarsening behavior, which is influenced by topological features such as triple junction and twin-relateddomain size distributions. Such findings underline the importance of capturing the correct topology of grain-boundary-engineered networks in simulations to reliably predict their evolution.