Improving coarsening resistance of dilute Al-Sc-Zr-Si alloys with Sr or Zn additions

Jeffrey D. Lin, David N Seidman, David C Dunand*

*Corresponding author for this work

Research output: Contribution to journalArticle

Abstract

We study the effect of a small addition of Zn (0.5 at.%) or a micro-addition of Sr (0.005 at.%) to a dilute Al-0.05Sc-0.07Zr-0.02Si (at.%) on precipitation of Al 3 (Sc,Zr) nanoprecipitates. Upon aging at 400 °C, both the Zn- and Sr-modified alloys retain peak-aged hardness (600 ± 10 MPa) for at least two weeks, while the Zn/Sr-free control alloy shows lower peak hardness (475 ± 8 MPa), which starts dropping after only 3 days. Similarly, peak hardness values achieved at 475 °C during isochronal aging, are much higher for the Zn/Sr-modified alloy (610 ± 10 and 590 ± 14 MPa) than for the Zn/Sr-free alloy (480 ± 5 MPa). Local electrode atom probe tomography shows that Sr and Zn atoms segregate to the Al 3 (Sc,Zr) nanoprecipitates: up to 0.1 at. % for Sr, and up to 1.1 at.% for Zn, with a peak of ∼5 at.% at the interface with the matrix. This may affect their coarsening rate by (i) reducing the diffusivity of Sc and Zr in the matrix and (ii) altering the precipitate/matrix interfacial energy. In the peak-aged condition, the Zn-modified alloy has the same creep resistance at 300 °C than the Zn-free control alloy, but its higher overaging resistance allows for longer creep operating times.

Original languageEnglish (US)
Pages (from-to)447-456
Number of pages10
JournalMaterials Science and Engineering A
Volume754
DOIs
StatePublished - Apr 29 2019

Fingerprint

Coarsening
hardness
Hardness
matrices
Aging of materials
creep strength
Atoms
Creep resistance
interfacial energy
high resistance
Interfacial energy
diffusivity
Tomography
atoms
Precipitates
precipitates
Creep
tomography
Electrodes
electrodes

Keywords

  • Aluminum alloys
  • Atom probe tomography
  • Creep resistance
  • Precipitation strengthening

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

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title = "Improving coarsening resistance of dilute Al-Sc-Zr-Si alloys with Sr or Zn additions",
abstract = "We study the effect of a small addition of Zn (0.5 at.{\%}) or a micro-addition of Sr (0.005 at.{\%}) to a dilute Al-0.05Sc-0.07Zr-0.02Si (at.{\%}) on precipitation of Al 3 (Sc,Zr) nanoprecipitates. Upon aging at 400 °C, both the Zn- and Sr-modified alloys retain peak-aged hardness (600 ± 10 MPa) for at least two weeks, while the Zn/Sr-free control alloy shows lower peak hardness (475 ± 8 MPa), which starts dropping after only 3 days. Similarly, peak hardness values achieved at 475 °C during isochronal aging, are much higher for the Zn/Sr-modified alloy (610 ± 10 and 590 ± 14 MPa) than for the Zn/Sr-free alloy (480 ± 5 MPa). Local electrode atom probe tomography shows that Sr and Zn atoms segregate to the Al 3 (Sc,Zr) nanoprecipitates: up to 0.1 at. {\%} for Sr, and up to 1.1 at.{\%} for Zn, with a peak of ∼5 at.{\%} at the interface with the matrix. This may affect their coarsening rate by (i) reducing the diffusivity of Sc and Zr in the matrix and (ii) altering the precipitate/matrix interfacial energy. In the peak-aged condition, the Zn-modified alloy has the same creep resistance at 300 °C than the Zn-free control alloy, but its higher overaging resistance allows for longer creep operating times.",
keywords = "Aluminum alloys, Atom probe tomography, Creep resistance, Precipitation strengthening",
author = "Lin, {Jeffrey D.} and Seidman, {David N} and Dunand, {David C}",
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Improving coarsening resistance of dilute Al-Sc-Zr-Si alloys with Sr or Zn additions. / Lin, Jeffrey D.; Seidman, David N; Dunand, David C.

In: Materials Science and Engineering A, Vol. 754, 29.04.2019, p. 447-456.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Improving coarsening resistance of dilute Al-Sc-Zr-Si alloys with Sr or Zn additions

AU - Lin, Jeffrey D.

AU - Seidman, David N

AU - Dunand, David C

PY - 2019/4/29

Y1 - 2019/4/29

N2 - We study the effect of a small addition of Zn (0.5 at.%) or a micro-addition of Sr (0.005 at.%) to a dilute Al-0.05Sc-0.07Zr-0.02Si (at.%) on precipitation of Al 3 (Sc,Zr) nanoprecipitates. Upon aging at 400 °C, both the Zn- and Sr-modified alloys retain peak-aged hardness (600 ± 10 MPa) for at least two weeks, while the Zn/Sr-free control alloy shows lower peak hardness (475 ± 8 MPa), which starts dropping after only 3 days. Similarly, peak hardness values achieved at 475 °C during isochronal aging, are much higher for the Zn/Sr-modified alloy (610 ± 10 and 590 ± 14 MPa) than for the Zn/Sr-free alloy (480 ± 5 MPa). Local electrode atom probe tomography shows that Sr and Zn atoms segregate to the Al 3 (Sc,Zr) nanoprecipitates: up to 0.1 at. % for Sr, and up to 1.1 at.% for Zn, with a peak of ∼5 at.% at the interface with the matrix. This may affect their coarsening rate by (i) reducing the diffusivity of Sc and Zr in the matrix and (ii) altering the precipitate/matrix interfacial energy. In the peak-aged condition, the Zn-modified alloy has the same creep resistance at 300 °C than the Zn-free control alloy, but its higher overaging resistance allows for longer creep operating times.

AB - We study the effect of a small addition of Zn (0.5 at.%) or a micro-addition of Sr (0.005 at.%) to a dilute Al-0.05Sc-0.07Zr-0.02Si (at.%) on precipitation of Al 3 (Sc,Zr) nanoprecipitates. Upon aging at 400 °C, both the Zn- and Sr-modified alloys retain peak-aged hardness (600 ± 10 MPa) for at least two weeks, while the Zn/Sr-free control alloy shows lower peak hardness (475 ± 8 MPa), which starts dropping after only 3 days. Similarly, peak hardness values achieved at 475 °C during isochronal aging, are much higher for the Zn/Sr-modified alloy (610 ± 10 and 590 ± 14 MPa) than for the Zn/Sr-free alloy (480 ± 5 MPa). Local electrode atom probe tomography shows that Sr and Zn atoms segregate to the Al 3 (Sc,Zr) nanoprecipitates: up to 0.1 at. % for Sr, and up to 1.1 at.% for Zn, with a peak of ∼5 at.% at the interface with the matrix. This may affect their coarsening rate by (i) reducing the diffusivity of Sc and Zr in the matrix and (ii) altering the precipitate/matrix interfacial energy. In the peak-aged condition, the Zn-modified alloy has the same creep resistance at 300 °C than the Zn-free control alloy, but its higher overaging resistance allows for longer creep operating times.

KW - Aluminum alloys

KW - Atom probe tomography

KW - Creep resistance

KW - Precipitation strengthening

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U2 - 10.1016/j.msea.2019.03.104

DO - 10.1016/j.msea.2019.03.104

M3 - Article

VL - 754

SP - 447

EP - 456

JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing

SN - 0921-5093

ER -