Mechanical properties and optimization of the aging of a dilute Al-Sc-Er-Zr-Si alloy with a high Zr/Sc ratio

Anthony De Luca; David C. Dunand; David N. Seidman

doi:10.1016/j.actamat.2016.08.018

Mechanical properties and optimization of the aging of a dilute Al-Sc-Er-Zr-Si alloy with a high Zr/Sc ratio

Anthony De Luca^*, David C. Dunand, David N. Seidman

^*Corresponding author for this work

Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

42 Scopus citations

Abstract

Precipitation strengthening behavior during aging of an Al-0.014Sc-0.008Er-0.08Zr-0.10Si (at.%) alloy was investigated utilizing microhardness, electrical conductivity and scanning electron microscopy. This new composition, with a Sc/Zr ratio (in at.%) smaller than 1/5 represents a significant reduction of the alloy's cost, when compared to more usual Al-0.06Sc (at.%) based alloys with typical Sc/Zr ratios of 3. The research presented herein focuses on identifying the optimal homogenization duration at 640 °C and additionally the temperature range at which a single-step aging treatment will achieve the highest possible microhardness in the shortest time. Due to a compromise between dissolution of Er-Si rich primary precipitates, homogenization of the Zr distribution and precipitation of large Al₃Zr precipitates, 8 h at 640 °C appears to be the optimal homogenization duration for this alloy, leading to an hardness of 571 ± 22 MPa after aging for 24 h at 400 °C. To study the precipitation behavior of this low-Sc concentration alloy, isochronal aging to 575 °C with two different heating rates was performed. The small Sc concentration, compensated by a high Zr concentration, permits the alloy to achieve a similar peak microhardness during isochronal aging (587 ± 20 MPa) as the corresponding Sc-richer and Zr-leaner alloys. The isochronal aging experiments permits us to identify the best aging temperature as between 350 and 425 °C.

Original language	English (US)
Pages (from-to)	35-42
Number of pages	8
Journal	Acta Materialia
Volume	119
DOIs	https://doi.org/10.1016/j.actamat.2016.08.018
State	Published - Oct 15 2016

Keywords

Al-Sc-Er-Zr-Si alloy
High-temperature alloy
Mechanical properties
Microhardness
Precipitation strengthening

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

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@article{02eaf4be2e2e41e284d24a78aff15079,

title = "Mechanical properties and optimization of the aging of a dilute Al-Sc-Er-Zr-Si alloy with a high Zr/Sc ratio",

abstract = "Precipitation strengthening behavior during aging of an Al-0.014Sc-0.008Er-0.08Zr-0.10Si (at.%) alloy was investigated utilizing microhardness, electrical conductivity and scanning electron microscopy. This new composition, with a Sc/Zr ratio (in at.%) smaller than 1/5 represents a significant reduction of the alloy's cost, when compared to more usual Al-0.06Sc (at.%) based alloys with typical Sc/Zr ratios of 3. The research presented herein focuses on identifying the optimal homogenization duration at 640 °C and additionally the temperature range at which a single-step aging treatment will achieve the highest possible microhardness in the shortest time. Due to a compromise between dissolution of Er-Si rich primary precipitates, homogenization of the Zr distribution and precipitation of large Al3Zr precipitates, 8 h at 640 °C appears to be the optimal homogenization duration for this alloy, leading to an hardness of 571 ± 22 MPa after aging for 24 h at 400 °C. To study the precipitation behavior of this low-Sc concentration alloy, isochronal aging to 575 °C with two different heating rates was performed. The small Sc concentration, compensated by a high Zr concentration, permits the alloy to achieve a similar peak microhardness during isochronal aging (587 ± 20 MPa) as the corresponding Sc-richer and Zr-leaner alloys. The isochronal aging experiments permits us to identify the best aging temperature as between 350 and 425 °C.",

keywords = "Al-Sc-Er-Zr-Si alloy, High-temperature alloy, Mechanical properties, Microhardness, Precipitation strengthening",

author = "{De Luca}, Anthony and Dunand, {David C.} and Seidman, {David N.}",

note = "Funding Information: This research was sponsored by the Ford-Northwestern University Alliance . APT was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The local-electrode atom-probe tomograph at NUCAPT was acquired and upgraded with equipment grants from the MRI program of the National Science Foundation ( NSF DMR-0420532 ) and the DURIP program of the Office of Naval Research ( N00014-0400798 , N00014-0610539 , N00014-0910781 ). NUCAPT received support from the MRSEC program ( NSF DMR-1121262 ) at the Materials Research Center, SHyNE Resource ( NSF NNCI-1542205 ), and the Initiative for Sustainability and Energy at Northwestern (ISEN). This research made use of the EPIC facility (NU ANCE Center-Northwestern University), which receives support from the MRSEC program ( NSF DMR-1121262 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. The authors also gratefully acknowledge the Initiative for Sustainability and Energy at Northwestern (ISEN) for grants to upgrade the capabilities of NUCAPT. The authors kindly thank Drs. J. Boileau and B. Ghaffari (Ford) for numerous useful discussions. ",

year = "2016",

month = oct,

day = "15",

doi = "10.1016/j.actamat.2016.08.018",

language = "English (US)",

volume = "119",

pages = "35--42",

journal = "Acta Materialia",

issn = "1359-6454",

publisher = "Elsevier Limited",

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TY - JOUR

T1 - Mechanical properties and optimization of the aging of a dilute Al-Sc-Er-Zr-Si alloy with a high Zr/Sc ratio

AU - De Luca, Anthony

AU - Dunand, David C.

AU - Seidman, David N.

N1 - Funding Information: This research was sponsored by the Ford-Northwestern University Alliance . APT was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The local-electrode atom-probe tomograph at NUCAPT was acquired and upgraded with equipment grants from the MRI program of the National Science Foundation ( NSF DMR-0420532 ) and the DURIP program of the Office of Naval Research ( N00014-0400798 , N00014-0610539 , N00014-0910781 ). NUCAPT received support from the MRSEC program ( NSF DMR-1121262 ) at the Materials Research Center, SHyNE Resource ( NSF NNCI-1542205 ), and the Initiative for Sustainability and Energy at Northwestern (ISEN). This research made use of the EPIC facility (NU ANCE Center-Northwestern University), which receives support from the MRSEC program ( NSF DMR-1121262 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. The authors also gratefully acknowledge the Initiative for Sustainability and Energy at Northwestern (ISEN) for grants to upgrade the capabilities of NUCAPT. The authors kindly thank Drs. J. Boileau and B. Ghaffari (Ford) for numerous useful discussions.

PY - 2016/10/15

Y1 - 2016/10/15

N2 - Precipitation strengthening behavior during aging of an Al-0.014Sc-0.008Er-0.08Zr-0.10Si (at.%) alloy was investigated utilizing microhardness, electrical conductivity and scanning electron microscopy. This new composition, with a Sc/Zr ratio (in at.%) smaller than 1/5 represents a significant reduction of the alloy's cost, when compared to more usual Al-0.06Sc (at.%) based alloys with typical Sc/Zr ratios of 3. The research presented herein focuses on identifying the optimal homogenization duration at 640 °C and additionally the temperature range at which a single-step aging treatment will achieve the highest possible microhardness in the shortest time. Due to a compromise between dissolution of Er-Si rich primary precipitates, homogenization of the Zr distribution and precipitation of large Al3Zr precipitates, 8 h at 640 °C appears to be the optimal homogenization duration for this alloy, leading to an hardness of 571 ± 22 MPa after aging for 24 h at 400 °C. To study the precipitation behavior of this low-Sc concentration alloy, isochronal aging to 575 °C with two different heating rates was performed. The small Sc concentration, compensated by a high Zr concentration, permits the alloy to achieve a similar peak microhardness during isochronal aging (587 ± 20 MPa) as the corresponding Sc-richer and Zr-leaner alloys. The isochronal aging experiments permits us to identify the best aging temperature as between 350 and 425 °C.

AB - Precipitation strengthening behavior during aging of an Al-0.014Sc-0.008Er-0.08Zr-0.10Si (at.%) alloy was investigated utilizing microhardness, electrical conductivity and scanning electron microscopy. This new composition, with a Sc/Zr ratio (in at.%) smaller than 1/5 represents a significant reduction of the alloy's cost, when compared to more usual Al-0.06Sc (at.%) based alloys with typical Sc/Zr ratios of 3. The research presented herein focuses on identifying the optimal homogenization duration at 640 °C and additionally the temperature range at which a single-step aging treatment will achieve the highest possible microhardness in the shortest time. Due to a compromise between dissolution of Er-Si rich primary precipitates, homogenization of the Zr distribution and precipitation of large Al3Zr precipitates, 8 h at 640 °C appears to be the optimal homogenization duration for this alloy, leading to an hardness of 571 ± 22 MPa after aging for 24 h at 400 °C. To study the precipitation behavior of this low-Sc concentration alloy, isochronal aging to 575 °C with two different heating rates was performed. The small Sc concentration, compensated by a high Zr concentration, permits the alloy to achieve a similar peak microhardness during isochronal aging (587 ± 20 MPa) as the corresponding Sc-richer and Zr-leaner alloys. The isochronal aging experiments permits us to identify the best aging temperature as between 350 and 425 °C.

KW - Al-Sc-Er-Zr-Si alloy

KW - High-temperature alloy

KW - Mechanical properties

KW - Microhardness

KW - Precipitation strengthening

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U2 - 10.1016/j.actamat.2016.08.018

DO - 10.1016/j.actamat.2016.08.018

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JO - Acta Materialia

JF - Acta Materialia

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