Ambient- and elevated-temperature strengthening by Al3Zr-Nanoprecipitates and Al3Ni-Microfibers in a cast Al-2.9Ni-0.11Zr-0.02Si-0.005Er (at.%) alloy

Richard A. Michi; Jacques Perrin Toinin; David N. Seidman; David C. Dunand

doi:10.1016/j.msea.2019.05.018

Ambient- and elevated-temperature strengthening by Al₃Zr-Nanoprecipitates and Al₃Ni-Microfibers in a cast Al-2.9Ni-0.11Zr-0.02Si-0.005Er (at.%) alloy

Richard A. Michi, Jacques Perrin Toinin, David N. Seidman, David C. Dunand^*

^*Corresponding author for this work

Materials Science and Engineering

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

46 Scopus citations

Abstract

Strengthening mechanisms at ambient and elevated temperatures are studied in a cast Al-0.11Zr-0.02Si-0.005Er (at.%) alloy with a 2.86 at.% Ni addition, containing: (i) incoherent Al₃Ni microfibers formed during eutectic solidification; and (ii) coherent, equiaxed Al₃Zr (L1₂-structure) nanoprecipitates created on subsequent aging. Strengthening contributions from microfibers and nanoprecipitates are cooperative at ambient temperature, over the full range of Al₃Zr precipitation during under-, peak-, and over-aging states. In contrast, during compressive creep testing at 300 °C, the binary eutectic Al-Al₃Ni alloy is not further strengthened by the Al₃Zr nanoprecipitates, reflecting their lower number density (5.8 × 10²² m⁻³) in the regions between Al₃Ni microfibers, where load transfer and/or microfiber/dislocation interactions provide strengthening. Also, when the Al-0.11Zr-0.02Si-0.005Er (at.%) alloy is modified with very low Ni concentrations of 0.07 at.%, without Al₃Ni microfiber formation, the precipitation kinetics of Al₃Zr(L1₂) are unaffected and negligible amounts of Ni are measured in the nanoprecipitates. The binary Al-2.86Ni at.% alloys with Al₃Ni eutectic microfibers, with and without Al₃Zr nanoprecipitates, are significantly more creep resistant at 300 °C than dilute Al-Sc or Al-Zr alloys strengthened solely by Al₃Zr or Al₃Sc nanoprecipitates. Unlike Al-Zr alloys, their upper service temperature is, however, limited to ∼400 °C, above which Al₃Ni coarsening becomes rapid.

Original language	English (US)
Pages (from-to)	78-89
Number of pages	12
Journal	Materials Science and Engineering: A
Volume	759
DOIs	https://doi.org/10.1016/j.msea.2019.05.018
State	Published - Jun 24 2019

Funding

This research was supported by the Office of Naval Research ( N00014-16-1-2402 ). Atom-probe tomography was performed at the Northwestern University Center for Atom-Probe Tomography (NUCAPT). The LEAP tomograph at NUCAPT was purchased and upgraded with grants from the NSF-MRI ( DMR-0420532 ) and ONR-DURIP ( N00014-0400798 , N00014-0610539 , N00014-0910781 , N00014-1712870 ) programs. NUCAPT received support from the MRSEC program (NSF DMR-1720139 ) at the Materials Research Center, the SHyNE Resource (NSF ECCS-1542205 ), and the Initiative for Sustainability and Energy (ISEN) at Northwestern University. This work made use of the Materials Characterization and Imaging Facility which receives support from the MRSEC Program (NSF DMR-1720139 ) of the Materials Research Center at Northwestern University. This work also made use of the EPIC facility of Northwestern University's NUANCE Center, which has received support from the MRSEC program NSF DMR-1720139 ) at the Materials Research Center; the International Institute for Nanotechnology (IIN); and the State of Illinois, through the IIN. DNS and DCD disclose financial interests relative to Braidy Industries, which could potentially benefit from the outcomes of this research but did not influence its conduct, description, or interpretation.

Keywords

Al-Ni-Zr-Er alloy
Atom-probe tomography
Compressive creep
Microhardness

ASJC Scopus subject areas

General Materials Science
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

Access to Document

10.1016/j.msea.2019.05.018

Cite this

@article{a211c2caaeeb4ba0ae8e8b890575b6cf,

title = "Ambient- and elevated-temperature strengthening by Al3Zr-Nanoprecipitates and Al3Ni-Microfibers in a cast Al-2.9Ni-0.11Zr-0.02Si-0.005Er (at.%) alloy",

abstract = "Strengthening mechanisms at ambient and elevated temperatures are studied in a cast Al-0.11Zr-0.02Si-0.005Er (at.%) alloy with a 2.86 at.% Ni addition, containing: (i) incoherent Al3Ni microfibers formed during eutectic solidification; and (ii) coherent, equiaxed Al3Zr (L12-structure) nanoprecipitates created on subsequent aging. Strengthening contributions from microfibers and nanoprecipitates are cooperative at ambient temperature, over the full range of Al3Zr precipitation during under-, peak-, and over-aging states. In contrast, during compressive creep testing at 300 °C, the binary eutectic Al-Al3Ni alloy is not further strengthened by the Al3Zr nanoprecipitates, reflecting their lower number density (5.8 × 1022 m−3) in the regions between Al3Ni microfibers, where load transfer and/or microfiber/dislocation interactions provide strengthening. Also, when the Al-0.11Zr-0.02Si-0.005Er (at.%) alloy is modified with very low Ni concentrations of 0.07 at.%, without Al3Ni microfiber formation, the precipitation kinetics of Al3Zr(L12) are unaffected and negligible amounts of Ni are measured in the nanoprecipitates. The binary Al-2.86Ni at.% alloys with Al3Ni eutectic microfibers, with and without Al3Zr nanoprecipitates, are significantly more creep resistant at 300 °C than dilute Al-Sc or Al-Zr alloys strengthened solely by Al3Zr or Al3Sc nanoprecipitates. Unlike Al-Zr alloys, their upper service temperature is, however, limited to ∼400 °C, above which Al3Ni coarsening becomes rapid.",

keywords = "Al-Ni-Zr-Er alloy, Atom-probe tomography, Compressive creep, Microhardness",

author = "Michi, {Richard A.} and Toinin, {Jacques Perrin} and Seidman, {David N.} and Dunand, {David C.}",

note = "Publisher Copyright: {\textcopyright} 2019 Elsevier B.V.",

year = "2019",

month = jun,

day = "24",

doi = "10.1016/j.msea.2019.05.018",

language = "English (US)",

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T1 - Ambient- and elevated-temperature strengthening by Al3Zr-Nanoprecipitates and Al3Ni-Microfibers in a cast Al-2.9Ni-0.11Zr-0.02Si-0.005Er (at.%) alloy

AU - Michi, Richard A.

AU - Toinin, Jacques Perrin

AU - Seidman, David N.

AU - Dunand, David C.

PY - 2019/6/24

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N2 - Strengthening mechanisms at ambient and elevated temperatures are studied in a cast Al-0.11Zr-0.02Si-0.005Er (at.%) alloy with a 2.86 at.% Ni addition, containing: (i) incoherent Al3Ni microfibers formed during eutectic solidification; and (ii) coherent, equiaxed Al3Zr (L12-structure) nanoprecipitates created on subsequent aging. Strengthening contributions from microfibers and nanoprecipitates are cooperative at ambient temperature, over the full range of Al3Zr precipitation during under-, peak-, and over-aging states. In contrast, during compressive creep testing at 300 °C, the binary eutectic Al-Al3Ni alloy is not further strengthened by the Al3Zr nanoprecipitates, reflecting their lower number density (5.8 × 1022 m−3) in the regions between Al3Ni microfibers, where load transfer and/or microfiber/dislocation interactions provide strengthening. Also, when the Al-0.11Zr-0.02Si-0.005Er (at.%) alloy is modified with very low Ni concentrations of 0.07 at.%, without Al3Ni microfiber formation, the precipitation kinetics of Al3Zr(L12) are unaffected and negligible amounts of Ni are measured in the nanoprecipitates. The binary Al-2.86Ni at.% alloys with Al3Ni eutectic microfibers, with and without Al3Zr nanoprecipitates, are significantly more creep resistant at 300 °C than dilute Al-Sc or Al-Zr alloys strengthened solely by Al3Zr or Al3Sc nanoprecipitates. Unlike Al-Zr alloys, their upper service temperature is, however, limited to ∼400 °C, above which Al3Ni coarsening becomes rapid.

AB - Strengthening mechanisms at ambient and elevated temperatures are studied in a cast Al-0.11Zr-0.02Si-0.005Er (at.%) alloy with a 2.86 at.% Ni addition, containing: (i) incoherent Al3Ni microfibers formed during eutectic solidification; and (ii) coherent, equiaxed Al3Zr (L12-structure) nanoprecipitates created on subsequent aging. Strengthening contributions from microfibers and nanoprecipitates are cooperative at ambient temperature, over the full range of Al3Zr precipitation during under-, peak-, and over-aging states. In contrast, during compressive creep testing at 300 °C, the binary eutectic Al-Al3Ni alloy is not further strengthened by the Al3Zr nanoprecipitates, reflecting their lower number density (5.8 × 1022 m−3) in the regions between Al3Ni microfibers, where load transfer and/or microfiber/dislocation interactions provide strengthening. Also, when the Al-0.11Zr-0.02Si-0.005Er (at.%) alloy is modified with very low Ni concentrations of 0.07 at.%, without Al3Ni microfiber formation, the precipitation kinetics of Al3Zr(L12) are unaffected and negligible amounts of Ni are measured in the nanoprecipitates. The binary Al-2.86Ni at.% alloys with Al3Ni eutectic microfibers, with and without Al3Zr nanoprecipitates, are significantly more creep resistant at 300 °C than dilute Al-Sc or Al-Zr alloys strengthened solely by Al3Zr or Al3Sc nanoprecipitates. Unlike Al-Zr alloys, their upper service temperature is, however, limited to ∼400 °C, above which Al3Ni coarsening becomes rapid.

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KW - Microhardness

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