Phase separation kinetics of binary mixture in the influence of bond disorder: Sensitivity to quench temperature

Morphologies in phase separating systems can significantly influence the final properties of materials. We present extensive Monte Carlo (MC) simulation results on the segregation kinetics of the critical binary (AB) mixture with a fraction of bond disorder (BD) introduced in a regular manner. We focus on studying the effect of various quench temperatures on the growth kinetics and scaling properties of evolving morphologies. The two-dimensional (2d) kinetic Ising system with conserved spin exchange kinetics is used to model the system. We observe that domain morphologies change from their usual interconnected bicontinuous isotropic patterns at zero BD to short strips and lamellar patterns (anisotropy) with increasing BD at shallow quench. The domain evolution remains extremely slow at deep quench and for lower fractions of BD, and thus, morphologies appear very similar; however, we observed lamellar patterns at high BD. The scaling behavior represented by the correlation function and the structure factor changes significantly with quench depths for a higher fraction of BD. In contrast, a tiny deviation from the scaling is observed at a lower fraction of disorder for shallow quenches. The growth law is consistent with the Lifshitz-Slyozov (LS) growth law (\phi->1/3) for shallow quench and at low fractions of BD studied here. At a high fraction of BD, the length scale crossovers gradually from an early time LS growth to the diffusion dynamics (\phi->1/2) during intermediate times for both deep and shallow quenches. The domain growth freezes (\phi->0) to a finite size when the system evolves to an equilibrium (stable) lamellar morphology in the asymptotic time limit on the time scale of our simulation. However, no significant changes are observed in the scaling behavior at lower fractions of BD for the deep quench.

Samiksha Shrivastava, Awaneesh Singh · 2021