Finite-temperature grain boundary properties from quasistatic atomistics


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Date

2024-09

Publication Type

Journal Article

ETH Bibliography

yes

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Abstract

Grain boundary (GB) properties greatly influence the mechanical, electrical, and thermal response of polycrystalline materials. Most computational studies of GB properties at finite temperatures use molecular dynamics (MD), which is computationally expensive, limited in the range of accessible timescales, and requires cumbersome techniques like thermodynamic integration to estimate free energies. This restricts the reasonable computation (without incurring excessive computational expense) of GB properties to regimes that are often unrealistic, such as zero temperature or extremely high strain rates. Consequently, there is a need for simulation methodology that avoids the timescale limitations of MD, while providing reliable estimates of GB properties. The Gaussian Phase-Packet (GPP) method is a temporal coarse-graining technique that can predict relaxed atomic structures at finite temperature in the quasistatic limit. This work applies GPP, combined with the quasiharmonic approximation for computing the free energy, to the problem of determining the free energy and shear coupling factor of grain boundaries in metals over a range of realistic temperatures. Validation is achieved by comparison to thermodynamic integration and quasiharmonic approximation (QHA), which confirms that the presented approach captures relaxed-energy GB structures and shear coupling factors at finite temperature with a high degree of accuracy, and it performs significantly better than QHA on hydrostatically expanded 0 K structures.

Publication status

published

Editor

Book title

Volume

244

Pages / Article No.

113270

Publisher

Elsevier

Event

Edition / version

Methods

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Geographic location

Date collected

Date created

Subject

Grain boundaries; Free energy calculation; molecular dynamics; Atomistics; Multiscale modeling; Statistical mechanics

Organisational unit

09600 - Kochmann, Dennis / Kochmann, Dennis check_circle

Notes

Funding

770754 - Decoding the Mechanics of Metals by Coarse-Grained Atomistics (EC)

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