Segregation to grain boundaries in disordered systems: an application to a Ni-based multi-component alloy

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Hauptverfasser: Gehringer, Dominik, Romaner, Lorenz, Holec, David
Format: Preprint
Veröffentlicht: 2024
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author Gehringer, Dominik
Romaner, Lorenz
Holec, David
author_facet Gehringer, Dominik
Romaner, Lorenz
Holec, David
contents Segregation to defects, in particular to grain boundaries (GBs), is an unavoidable phenomenon leading to changed material behavior over time. With the increase of available computational power, unbiased quantum-mechanical predictions of segregation energies, which feed classical thermodynamics models of segregation (e.g., McLean isotherm), become available. In recent years, huge progress towards predictions closely resembling experimental observations was made by considering the statistical nature of the segregation process due to competing segregation sites at a single GB and/or many different types of co-existing GBs. In the present work, we further expand this field by explicitly showing how compositional disorder, present in real engineering alloys (e.g. steels or Ni-based superalloys), gives rise to a spectrum of segregation energies. With the example of a $Σ5$ GB in a Ni-based model alloy (Ni-Co-Cr-Ti-Al), we show that the segregation energies of Fe, Mn, W, Nb, and Zr are significantly different from those predicted for pure elemental Ni. We further use the predicted segregation energy spectra in a statistical evaluation of GB enrichment, which allows for extracting segregation enthalpy and segregation entropy terms related to the chemical complexity in multi-component alloys.
format Preprint
id arxiv_https___arxiv_org_abs_2407_11957
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Segregation to grain boundaries in disordered systems: an application to a Ni-based multi-component alloy
Gehringer, Dominik
Romaner, Lorenz
Holec, David
Materials Science
Mesoscale and Nanoscale Physics
Segregation to defects, in particular to grain boundaries (GBs), is an unavoidable phenomenon leading to changed material behavior over time. With the increase of available computational power, unbiased quantum-mechanical predictions of segregation energies, which feed classical thermodynamics models of segregation (e.g., McLean isotherm), become available. In recent years, huge progress towards predictions closely resembling experimental observations was made by considering the statistical nature of the segregation process due to competing segregation sites at a single GB and/or many different types of co-existing GBs. In the present work, we further expand this field by explicitly showing how compositional disorder, present in real engineering alloys (e.g. steels or Ni-based superalloys), gives rise to a spectrum of segregation energies. With the example of a $Σ5$ GB in a Ni-based model alloy (Ni-Co-Cr-Ti-Al), we show that the segregation energies of Fe, Mn, W, Nb, and Zr are significantly different from those predicted for pure elemental Ni. We further use the predicted segregation energy spectra in a statistical evaluation of GB enrichment, which allows for extracting segregation enthalpy and segregation entropy terms related to the chemical complexity in multi-component alloys.
title Segregation to grain boundaries in disordered systems: an application to a Ni-based multi-component alloy
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2407.11957