Effects of tungsten and rhenium additions on phase-separation in a model Ni-Al-Cr-W-Re superalloy

A four-dimensional study

Yanyan Huang*, Zugang Mao, Ronald D. Noebe, David N Seidman

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

The effects of a combined 1.0 at.% W and 1.0 at.% Re addition to a model Ni-10.0Al-8.5Cr at.% superalloy aged at 1073 K (800 °C) for aging times up to 256 h are investigated using atom-probe tomography (APT) and Vickers microhardness measurements. The nanoscale properties, including volume fraction, mean-volume equivalent-radius and number density of the γ′(L12)-precipitates, the chemical compositions of the γ(f.c.c.)-matrix and γ′(L12)-precipitates, the concentration profiles and partitioning ratios between the two phases, γ(f.c.c.)/γ′(L12), hetero-interfacial concentration widths, and microhardness are measured as function of increasing aging time. Localized excesses of the solvent Ni at the γ(f.c.c.)/γ′(L12) interfaces persist at aging times as long as 256 h. Transient diffusional concentration gradients associated with solute-atoms during diffusion-limited growth exist in either the γ(f.c.c.)-matrix or γ′(L12)-precipitates for the as-quenched state; these gradients disappear after 0.25 h for Al and Cr, and after 1 h for W and Re. Tungsten partitions to the γ′(L12)-precipitates and Re partitions to the γ(f.c.c.)-matrix, respectively, and this partitioning behavior enhances the partitioning of Al to the γ′(L12)-precipitates and Cr to the γ(f.c.c.)-matrix. The partitioning behavior indicates that W and Re evolve temporally more slowly than Al and Cr due to their small diffusivities in Ni. The interfacial concentration widths in the Ni-Al-Cr-W-Re alloy decrease with increasing aging time and increasing mean precipitate-radius. Adding W and Re to the base Ni-10.0Al-8.5Cr at.% alloy increases the γ′(L12)-precipitate volume fraction and the microhardness due to the increased volume-fraction and solid-solution strengthening provided by W and Re.

Original languageEnglish (US)
Pages (from-to)377-388
Number of pages12
JournalJournal of Alloys and Compounds
DOIs
StatePublished - Aug 30 2019

Fingerprint

Rhenium
Tungsten
Superalloys
Phase separation
Precipitates
Aging of materials
Microhardness
Volume fraction
Atoms
Tomography
Solid solutions
Chemical analysis

Keywords

  • Atom-probe tomography
  • Ni-based superalloys
  • Precipitation
  • Rhenium
  • Tungsten

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

@article{05551401cec6401faca867e067e53b37,
title = "Effects of tungsten and rhenium additions on phase-separation in a model Ni-Al-Cr-W-Re superalloy: A four-dimensional study",
abstract = "The effects of a combined 1.0 at.{\%} W and 1.0 at.{\%} Re addition to a model Ni-10.0Al-8.5Cr at.{\%} superalloy aged at 1073 K (800 °C) for aging times up to 256 h are investigated using atom-probe tomography (APT) and Vickers microhardness measurements. The nanoscale properties, including volume fraction, mean-volume equivalent-radius and number density of the γ′(L12)-precipitates, the chemical compositions of the γ(f.c.c.)-matrix and γ′(L12)-precipitates, the concentration profiles and partitioning ratios between the two phases, γ(f.c.c.)/γ′(L12), hetero-interfacial concentration widths, and microhardness are measured as function of increasing aging time. Localized excesses of the solvent Ni at the γ(f.c.c.)/γ′(L12) interfaces persist at aging times as long as 256 h. Transient diffusional concentration gradients associated with solute-atoms during diffusion-limited growth exist in either the γ(f.c.c.)-matrix or γ′(L12)-precipitates for the as-quenched state; these gradients disappear after 0.25 h for Al and Cr, and after 1 h for W and Re. Tungsten partitions to the γ′(L12)-precipitates and Re partitions to the γ(f.c.c.)-matrix, respectively, and this partitioning behavior enhances the partitioning of Al to the γ′(L12)-precipitates and Cr to the γ(f.c.c.)-matrix. The partitioning behavior indicates that W and Re evolve temporally more slowly than Al and Cr due to their small diffusivities in Ni. The interfacial concentration widths in the Ni-Al-Cr-W-Re alloy decrease with increasing aging time and increasing mean precipitate-radius. Adding W and Re to the base Ni-10.0Al-8.5Cr at.{\%} alloy increases the γ′(L12)-precipitate volume fraction and the microhardness due to the increased volume-fraction and solid-solution strengthening provided by W and Re.",
keywords = "Atom-probe tomography, Ni-based superalloys, Precipitation, Rhenium, Tungsten",
author = "Yanyan Huang and Zugang Mao and Noebe, {Ronald D.} and Seidman, {David N}",
year = "2019",
month = "8",
day = "30",
doi = "10.1016/j.jallcom.2019.05.292",
language = "English (US)",
pages = "377--388",
journal = "Journal of Alloys and Compounds",
issn = "0925-8388",
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}

Effects of tungsten and rhenium additions on phase-separation in a model Ni-Al-Cr-W-Re superalloy : A four-dimensional study. / Huang, Yanyan; Mao, Zugang; Noebe, Ronald D.; Seidman, David N.

In: Journal of Alloys and Compounds, 30.08.2019, p. 377-388.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of tungsten and rhenium additions on phase-separation in a model Ni-Al-Cr-W-Re superalloy

T2 - A four-dimensional study

AU - Huang, Yanyan

AU - Mao, Zugang

AU - Noebe, Ronald D.

AU - Seidman, David N

PY - 2019/8/30

Y1 - 2019/8/30

N2 - The effects of a combined 1.0 at.% W and 1.0 at.% Re addition to a model Ni-10.0Al-8.5Cr at.% superalloy aged at 1073 K (800 °C) for aging times up to 256 h are investigated using atom-probe tomography (APT) and Vickers microhardness measurements. The nanoscale properties, including volume fraction, mean-volume equivalent-radius and number density of the γ′(L12)-precipitates, the chemical compositions of the γ(f.c.c.)-matrix and γ′(L12)-precipitates, the concentration profiles and partitioning ratios between the two phases, γ(f.c.c.)/γ′(L12), hetero-interfacial concentration widths, and microhardness are measured as function of increasing aging time. Localized excesses of the solvent Ni at the γ(f.c.c.)/γ′(L12) interfaces persist at aging times as long as 256 h. Transient diffusional concentration gradients associated with solute-atoms during diffusion-limited growth exist in either the γ(f.c.c.)-matrix or γ′(L12)-precipitates for the as-quenched state; these gradients disappear after 0.25 h for Al and Cr, and after 1 h for W and Re. Tungsten partitions to the γ′(L12)-precipitates and Re partitions to the γ(f.c.c.)-matrix, respectively, and this partitioning behavior enhances the partitioning of Al to the γ′(L12)-precipitates and Cr to the γ(f.c.c.)-matrix. The partitioning behavior indicates that W and Re evolve temporally more slowly than Al and Cr due to their small diffusivities in Ni. The interfacial concentration widths in the Ni-Al-Cr-W-Re alloy decrease with increasing aging time and increasing mean precipitate-radius. Adding W and Re to the base Ni-10.0Al-8.5Cr at.% alloy increases the γ′(L12)-precipitate volume fraction and the microhardness due to the increased volume-fraction and solid-solution strengthening provided by W and Re.

AB - The effects of a combined 1.0 at.% W and 1.0 at.% Re addition to a model Ni-10.0Al-8.5Cr at.% superalloy aged at 1073 K (800 °C) for aging times up to 256 h are investigated using atom-probe tomography (APT) and Vickers microhardness measurements. The nanoscale properties, including volume fraction, mean-volume equivalent-radius and number density of the γ′(L12)-precipitates, the chemical compositions of the γ(f.c.c.)-matrix and γ′(L12)-precipitates, the concentration profiles and partitioning ratios between the two phases, γ(f.c.c.)/γ′(L12), hetero-interfacial concentration widths, and microhardness are measured as function of increasing aging time. Localized excesses of the solvent Ni at the γ(f.c.c.)/γ′(L12) interfaces persist at aging times as long as 256 h. Transient diffusional concentration gradients associated with solute-atoms during diffusion-limited growth exist in either the γ(f.c.c.)-matrix or γ′(L12)-precipitates for the as-quenched state; these gradients disappear after 0.25 h for Al and Cr, and after 1 h for W and Re. Tungsten partitions to the γ′(L12)-precipitates and Re partitions to the γ(f.c.c.)-matrix, respectively, and this partitioning behavior enhances the partitioning of Al to the γ′(L12)-precipitates and Cr to the γ(f.c.c.)-matrix. The partitioning behavior indicates that W and Re evolve temporally more slowly than Al and Cr due to their small diffusivities in Ni. The interfacial concentration widths in the Ni-Al-Cr-W-Re alloy decrease with increasing aging time and increasing mean precipitate-radius. Adding W and Re to the base Ni-10.0Al-8.5Cr at.% alloy increases the γ′(L12)-precipitate volume fraction and the microhardness due to the increased volume-fraction and solid-solution strengthening provided by W and Re.

KW - Atom-probe tomography

KW - Ni-based superalloys

KW - Precipitation

KW - Rhenium

KW - Tungsten

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U2 - 10.1016/j.jallcom.2019.05.292

DO - 10.1016/j.jallcom.2019.05.292

M3 - Article

SP - 377

EP - 388

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

SN - 0925-8388

ER -