Slow relaxation of cascade-induced defects in Fe

Abstract

On-the-fly kinetic Monte Carlo (KMC) simulations are performed to investigate slow relaxation of non-equilibrium systems. Point defects induced by 25 keV cascades in $\alpha$-Fe are shown to lead to a characteristic time-evolution, described by the \emph{replenish and relax} mechanism. Then, we produce an atomistically-based assessment of models proposed to explain the slow structural relaxation by focusing on the aggregation of 50 vacancies and 25 self-interstital atoms (SIA) in 10-lattice-parameter $\alpha$-Fe boxes, two processes that are closely related to cascade annealing and exhibit similar time signature. Four atomistic effects explain the timescales involved in the evolution: defect concentration heterogeneities, concentration-enhanced mobility, cluster-size dependent bond energies and defect-induced pressure. These findings suggest that the two main classes of models to explain slow structural relaxation, the Eyring model and the Gibbs model, both play a role to limit the rate of relaxation of these simple point-defect systems.

References in corpus (10)

• Colloidal Gels: Equilibrium and Non-Equilibrium Routes
• The Kinetic Activation-Relaxation Technique: A Powerful Off-lattice On-the-fly Kinetic Monte Carlo Algorithm
• Logarithmic Relaxation in Glass-Forming Systems
• Simulations of aging and plastic deformation in polymer glasses
• Logarithmic Relaxation in a Colloidal System
• Slow dynamics and stress relaxation in a liquid as an elastic medium
• Understanding long-time vacancy aggregation in iron: a kinetic activation-relaxation technique study
• Nearly-logarithmic decay in the colloidal hard-sphere system
• Replenish and relax: explaining logarithmic annealing in disordered materials
• Strain effect and intermixing at the Si surface: A hybrid quantum and molecular mechanics study

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