Atomistic simulations of driven alloys: a study of effective temperature models for low and high temperature applications
type: CreativeWork
description: Immiscible alloys under severe plastic deformation (SPD) or irradiation form non-equilibrium microstructures at steady-state with microstructural features of a characteristic length scale that are stable over prolonged processing times. Such alloys have been termed ‘driven alloys’ as these steady-state microstructures are formed and stabilized as a consequence of the dynamical competition between the applied extrinsic driving force that tends to homogenize the microstructure and the thermodynamic driving force restoring its phase-separated equilibrium state. In recent years, non-equilibrium processing of immiscible alloys by SPD or ion-beam mixing have attracted significant interest as they enable the synthesis of novel nano-composite alloys with desirable properties such as enhanced mechanical strength, high electrical/thermal conductivity, creep resistance and radiation tolerance. Nonetheless, some major roadblocks must be overcome before the promise of these alloys can be realized. Currently, there is no general theoretical framework that can predict the microstructures formed under driven conditions. Furthermore, the present understanding of the mechanisms underlying microstructural evolution in driven alloys is still rather limited. One approach to rationalize the novel microstructure that evolves in driven alloys has been the effective temperature model (ETM) which posits that the non-equilibrium phases formed during processing will correspond to the equilibrium phase at a different, typically higher, effective temperature different from the ambient one. The underlying intuition behind this model is that the extrinsic forcing via irradiation or SPD represents an entropy-like contribution to the free energy of the system. Thus, to a first approximation, the evolution of driven alloys will be determined by the relative magnitudes, captured in the forcing intensity parameter, of the chemical diffusivities corresponding to ballistic mixing and vacancy-mediated the…
abstract: Immiscible alloys under severe plastic deformation (SPD) or irradiation form non-equilibrium microstructures at steady-state with microstructural features of a characteristic length scale that are stable over prolonged processing times. Such alloys have been termed ‘driven alloys’ as these steady-state microstructures are formed and stabilized as a consequence of the dynamical competition between the applied extrinsic driving force that tends to homogenize the microstructure and the thermodynamic driving force restoring its phase-separated equilibrium state. In recent years, non-equilibrium processing of immiscible alloys by SPD or ion-beam mixing have attracted significant interest as they enable the synthesis of novel nano-composite alloys with desirable properties such as enhanced mechanical strength, high electrical/thermal conductivity, creep resistance and radiation tolerance. Nonetheless, some major roadblocks must be overcome before the promise of these alloys can be realized. Currently, there is no general theoretical framework that can predict the microstructures formed under driven conditions. Furthermore, the present understanding of the mechanisms underlying microstructural evolution in driven alloys is still rather limited. One approach to rationalize the novel microstructure that evolves in driven alloys has been the effective temperature model (ETM) which posits that the non-equilibrium phases formed during processing will correspond to the equilibrium phase at a different, typically higher, effective temperature different from the ambient one. The underlying intuition behind this model is that the extrinsic forcing via irradiation or SPD represents an entropy-like contribution to the free energy of the system. Thus, to a first approximation, the evolution of driven alloys will be determined by the relative magnitudes, captured in the forcing intensity parameter, of the chemical diffusivities corresponding to ballistic mixing and vacancy-mediated the…
author: Pant, Nirab
language: en
keywords: Driven Alloys, Effective Temperature Model, Atomistic Simulations, Molecular Dynamics, Kinetic Monte Carlo, Severe Plastic Deformation, Irradiation, Immiscible Alloys, Patterning, Non-equilibrium Processing
date published: 2021-03-05T21:38:07Z
date modified: 2026-07-22T22:24:50Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/109393