Immobile defects in ferroelastic walls: Wall nucleation at defect sites

Abstract

Randomly distributed, static defects are enriched in ferroelastic domain walls. The relative concentration of defects in walls, Nd, follows a power law distribution as a function of the total defect concentration C: Nd∼Cα with α=0.4. The enrichment Nd/C ranges from ∼50 times when C = 10 ppm to ∼3 times when C = 1000 ppm. The resulting enrichment is due to nucleation at defect sites as observed in large scale MD simulations. The dynamics of domain nucleation and switching is dependent on the defect concentration. Their energy distribution follows the power law with exponents during yield between ε∼1.82 and 2.0 when the defect concentration increases. The power law exponent is ε≈2.7 in the plastic regime, independent of the defect concentration.