Effects of Sb micro-alloying on precipitate evolution and mechanical properties of a dilute Al-Sc-Zr alloy

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

*Corresponding author for this work

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

An Al-Sc-Zr aluminum alloy with Sb micro-addition (Al-0.066Sc-0.050Zr-0.021Sb at%) is cast and heat-treated to study the effects of Sb on the nucleation, growth, coarsening kinetics and precipitate morphology, and resulting mechanical properties at ambient and elevated temperatures. When isochronally aged, the Sb-containing alloy exhibits a peak microhardness (607±12 MPa) at 475 °C, which is greater than that of a comparable Sb-free alloy at the same temperature (549±17 MPa), and a smaller rate of decrease of microhardness values due to precipitate coarsening for aging temperatures >475 °C. When isothermally aged, the Sb-containing alloy achieves larger peak microhardness values at 300 °C for more than a month (~80 MPa difference) and 400 °C for ~8 h (~200 MPa difference) than the Sb-free alloy. Atom-probe tomography of the peak-aged Sb-containing alloy demonstrates that Sb partitions to the precipitates, and is enriched in the Zr-rich shell (up to 0.35 at% Sb). For creep testing at 300 °C, the Sb-containing alloy exhibits smaller steady-state strain-rates than the Sb-free control alloy at applied stresses >15 MPa. It is hypothesized that the effects of Sb micro-alloying (partitioning to precipitates, enhanced precipitate coarsening and higher creep resistance) are linked with the following mechanisms: (i) enhanced Zr diffusion in the matrix due to attractive Sb-Zr interactions; (ii) reduction in matrix/precipitate interfacial free energy, when Sb is present; and (iii) an increase in precipitate/matrix lattice parameter mismatch resulting in stronger elastic interactions with dislocations.

Original languageEnglish (US)
Pages (from-to)64-74
Number of pages11
JournalMaterials Science and Engineering A
Volume680
DOIs
StatePublished - Jan 5 2017

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Alloying
alloying
Precipitates
precipitates
mechanical properties
Mechanical properties
Coarsening
Microhardness
microhardness
matrices
Creep testing
creep strength
Creep resistance
aluminum alloys
Temperature
Free energy
ambient temperature
Lattice constants
strain rate
Tomography

Keywords

  • Alloys
  • Aluminum
  • L1
  • Precipitation
  • Scandium
  • Zirconium

ASJC Scopus subject areas

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

Cite this

@article{0c27c936e88d4978a4967335587dc186,
title = "Effects of Sb micro-alloying on precipitate evolution and mechanical properties of a dilute Al-Sc-Zr alloy",
abstract = "An Al-Sc-Zr aluminum alloy with Sb micro-addition (Al-0.066Sc-0.050Zr-0.021Sb at{\%}) is cast and heat-treated to study the effects of Sb on the nucleation, growth, coarsening kinetics and precipitate morphology, and resulting mechanical properties at ambient and elevated temperatures. When isochronally aged, the Sb-containing alloy exhibits a peak microhardness (607±12 MPa) at 475 °C, which is greater than that of a comparable Sb-free alloy at the same temperature (549±17 MPa), and a smaller rate of decrease of microhardness values due to precipitate coarsening for aging temperatures >475 °C. When isothermally aged, the Sb-containing alloy achieves larger peak microhardness values at 300 °C for more than a month (~80 MPa difference) and 400 °C for ~8 h (~200 MPa difference) than the Sb-free alloy. Atom-probe tomography of the peak-aged Sb-containing alloy demonstrates that Sb partitions to the precipitates, and is enriched in the Zr-rich shell (up to 0.35 at{\%} Sb). For creep testing at 300 °C, the Sb-containing alloy exhibits smaller steady-state strain-rates than the Sb-free control alloy at applied stresses >15 MPa. It is hypothesized that the effects of Sb micro-alloying (partitioning to precipitates, enhanced precipitate coarsening and higher creep resistance) are linked with the following mechanisms: (i) enhanced Zr diffusion in the matrix due to attractive Sb-Zr interactions; (ii) reduction in matrix/precipitate interfacial free energy, when Sb is present; and (iii) an increase in precipitate/matrix lattice parameter mismatch resulting in stronger elastic interactions with dislocations.",
keywords = "Alloys, Aluminum, L1, Precipitation, Scandium, Zirconium",
author = "Lin, {Jeffrey D.} and Philipp Okle and Dunand, {David C} and Seidman, {David N}",
year = "2017",
month = "1",
day = "5",
doi = "10.1016/j.msea.2016.10.067",
language = "English (US)",
volume = "680",
pages = "64--74",
journal = "Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing",
issn = "0921-5093",
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}

Effects of Sb micro-alloying on precipitate evolution and mechanical properties of a dilute Al-Sc-Zr alloy. / Lin, Jeffrey D.; Okle, Philipp; Dunand, David C; Seidman, David N.

In: Materials Science and Engineering A, Vol. 680, 05.01.2017, p. 64-74.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effects of Sb micro-alloying on precipitate evolution and mechanical properties of a dilute Al-Sc-Zr alloy

AU - Lin, Jeffrey D.

AU - Okle, Philipp

AU - Dunand, David C

AU - Seidman, David N

PY - 2017/1/5

Y1 - 2017/1/5

N2 - An Al-Sc-Zr aluminum alloy with Sb micro-addition (Al-0.066Sc-0.050Zr-0.021Sb at%) is cast and heat-treated to study the effects of Sb on the nucleation, growth, coarsening kinetics and precipitate morphology, and resulting mechanical properties at ambient and elevated temperatures. When isochronally aged, the Sb-containing alloy exhibits a peak microhardness (607±12 MPa) at 475 °C, which is greater than that of a comparable Sb-free alloy at the same temperature (549±17 MPa), and a smaller rate of decrease of microhardness values due to precipitate coarsening for aging temperatures >475 °C. When isothermally aged, the Sb-containing alloy achieves larger peak microhardness values at 300 °C for more than a month (~80 MPa difference) and 400 °C for ~8 h (~200 MPa difference) than the Sb-free alloy. Atom-probe tomography of the peak-aged Sb-containing alloy demonstrates that Sb partitions to the precipitates, and is enriched in the Zr-rich shell (up to 0.35 at% Sb). For creep testing at 300 °C, the Sb-containing alloy exhibits smaller steady-state strain-rates than the Sb-free control alloy at applied stresses >15 MPa. It is hypothesized that the effects of Sb micro-alloying (partitioning to precipitates, enhanced precipitate coarsening and higher creep resistance) are linked with the following mechanisms: (i) enhanced Zr diffusion in the matrix due to attractive Sb-Zr interactions; (ii) reduction in matrix/precipitate interfacial free energy, when Sb is present; and (iii) an increase in precipitate/matrix lattice parameter mismatch resulting in stronger elastic interactions with dislocations.

AB - An Al-Sc-Zr aluminum alloy with Sb micro-addition (Al-0.066Sc-0.050Zr-0.021Sb at%) is cast and heat-treated to study the effects of Sb on the nucleation, growth, coarsening kinetics and precipitate morphology, and resulting mechanical properties at ambient and elevated temperatures. When isochronally aged, the Sb-containing alloy exhibits a peak microhardness (607±12 MPa) at 475 °C, which is greater than that of a comparable Sb-free alloy at the same temperature (549±17 MPa), and a smaller rate of decrease of microhardness values due to precipitate coarsening for aging temperatures >475 °C. When isothermally aged, the Sb-containing alloy achieves larger peak microhardness values at 300 °C for more than a month (~80 MPa difference) and 400 °C for ~8 h (~200 MPa difference) than the Sb-free alloy. Atom-probe tomography of the peak-aged Sb-containing alloy demonstrates that Sb partitions to the precipitates, and is enriched in the Zr-rich shell (up to 0.35 at% Sb). For creep testing at 300 °C, the Sb-containing alloy exhibits smaller steady-state strain-rates than the Sb-free control alloy at applied stresses >15 MPa. It is hypothesized that the effects of Sb micro-alloying (partitioning to precipitates, enhanced precipitate coarsening and higher creep resistance) are linked with the following mechanisms: (i) enhanced Zr diffusion in the matrix due to attractive Sb-Zr interactions; (ii) reduction in matrix/precipitate interfacial free energy, when Sb is present; and (iii) an increase in precipitate/matrix lattice parameter mismatch resulting in stronger elastic interactions with dislocations.

KW - Alloys

KW - Aluminum

KW - L1

KW - Precipitation

KW - Scandium

KW - Zirconium

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U2 - 10.1016/j.msea.2016.10.067

DO - 10.1016/j.msea.2016.10.067

M3 - Article

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VL - 680

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EP - 74

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 -