Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during aging at 450-600 °C

Keith E. Knipling; David C. Dunand; David N. Seidman

doi:10.1016/j.actamat.2007.11.011

Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during aging at 450-600 °C

Keith E. Knipling^*, David C. Dunand, David N. Seidman

^*Corresponding author for this work

Materials Science and Engineering

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

174 Scopus citations

Abstract

The transformation of Al₃Zr (L1₂) and Al₃(Zr_1-xTi_x) (L1₂) precipitates to their respective equilibrium D0₂₃ structures is investigated in conventionally solidified Al-0.1Zr and Al-0.1Zr-0.1Ti (at.%) alloys aged isothermally at 500 °C or aged isochronally in the range 300-600 °C. Titanium additions delay neither coarsening of the metastable L1₂ precipitates nor their transformation to the D0₂₃ structure. Both alloys overage at the same rate at or above 500 °C, during which spheroidal L1₂ precipitates transform to disk-shaped D0₂₃ precipitates at ca. 200 nm in diameter and 50 nm in thickness, exhibiting a cube-on-cube orientation relationship with the α-Al matrix. The transformation occurs heterogeneously on dislocations because of a large lattice parameter mismatch of the D0₂₃ phase with α-Al. The transformation is very sluggish and even at 575 °C coherent L1₂ precipitates can remain untransformed. Mechanisms of microstructural coarsening and strengthening are discussed with respect to the micrometer-scale dendritic distribution of precipitates.

Original language	English (US)
Pages (from-to)	1182-1195
Number of pages	14
Journal	Acta Materialia
Volume	56
Issue number	6
DOIs	https://doi.org/10.1016/j.actamat.2007.11.011
State	Published - Apr 2008

Keywords

Aluminum alloys
Coarsening
Precipitation strengthening
Titanium
Zirconium

ASJC Scopus subject areas

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

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@article{63c484f021ad40bbb1b4a50b20847912,

title = "Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during aging at 450-600 °C",

abstract = "The transformation of Al3Zr (L12) and Al3(Zr1-xTix) (L12) precipitates to their respective equilibrium D023 structures is investigated in conventionally solidified Al-0.1Zr and Al-0.1Zr-0.1Ti (at.%) alloys aged isothermally at 500 °C or aged isochronally in the range 300-600 °C. Titanium additions delay neither coarsening of the metastable L12 precipitates nor their transformation to the D023 structure. Both alloys overage at the same rate at or above 500 °C, during which spheroidal L12 precipitates transform to disk-shaped D023 precipitates at ca. 200 nm in diameter and 50 nm in thickness, exhibiting a cube-on-cube orientation relationship with the α-Al matrix. The transformation occurs heterogeneously on dislocations because of a large lattice parameter mismatch of the D023 phase with α-Al. The transformation is very sluggish and even at 575 °C coherent L12 precipitates can remain untransformed. Mechanisms of microstructural coarsening and strengthening are discussed with respect to the micrometer-scale dendritic distribution of precipitates.",

keywords = "Aluminum alloys, Coarsening, Precipitation strengthening, Titanium, Zirconium",

author = "Knipling, {Keith E.} and Dunand, {David C.} and Seidman, {David N.}",

note = "Funding Information: This research is supported by the US Department of Energy, Basic Sciences Division, under contracts DE-FG02-02ER45997 and DE-FG02-98ER45721. K.E.K. acknowledges additional support during manuscript preparation at the Naval Research Laboratory by the National Research Council under the Research Associateship Programs. We kindly thank Dr J.L. Murray (Alcoa) for her calculations concerning the ternary Al–Zr–Ti system. We are pleased to acknowledge Profs M. Asta, M.E. Fine, D. Isheim (Northwestern University), and W.T. Reynolds (Virginia Tech) for useful discussions. We thank also Ms C.P. Lee (a Northwestern University undergraduate student) for assistance with the microhardness and AC electrical conductivity measurements.",

year = "2008",

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doi = "10.1016/j.actamat.2007.11.011",

language = "English (US)",

volume = "56",

pages = "1182--1195",

journal = "Acta Materialia",

issn = "1359-6454",

publisher = "Elsevier Limited",

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T1 - Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during aging at 450-600 °C

AU - Knipling, Keith E.

AU - Dunand, David C.

AU - Seidman, David N.

N1 - Funding Information: This research is supported by the US Department of Energy, Basic Sciences Division, under contracts DE-FG02-02ER45997 and DE-FG02-98ER45721. K.E.K. acknowledges additional support during manuscript preparation at the Naval Research Laboratory by the National Research Council under the Research Associateship Programs. We kindly thank Dr J.L. Murray (Alcoa) for her calculations concerning the ternary Al–Zr–Ti system. We are pleased to acknowledge Profs M. Asta, M.E. Fine, D. Isheim (Northwestern University), and W.T. Reynolds (Virginia Tech) for useful discussions. We thank also Ms C.P. Lee (a Northwestern University undergraduate student) for assistance with the microhardness and AC electrical conductivity measurements.

PY - 2008/4

Y1 - 2008/4

N2 - The transformation of Al3Zr (L12) and Al3(Zr1-xTix) (L12) precipitates to their respective equilibrium D023 structures is investigated in conventionally solidified Al-0.1Zr and Al-0.1Zr-0.1Ti (at.%) alloys aged isothermally at 500 °C or aged isochronally in the range 300-600 °C. Titanium additions delay neither coarsening of the metastable L12 precipitates nor their transformation to the D023 structure. Both alloys overage at the same rate at or above 500 °C, during which spheroidal L12 precipitates transform to disk-shaped D023 precipitates at ca. 200 nm in diameter and 50 nm in thickness, exhibiting a cube-on-cube orientation relationship with the α-Al matrix. The transformation occurs heterogeneously on dislocations because of a large lattice parameter mismatch of the D023 phase with α-Al. The transformation is very sluggish and even at 575 °C coherent L12 precipitates can remain untransformed. Mechanisms of microstructural coarsening and strengthening are discussed with respect to the micrometer-scale dendritic distribution of precipitates.

AB - The transformation of Al3Zr (L12) and Al3(Zr1-xTix) (L12) precipitates to their respective equilibrium D023 structures is investigated in conventionally solidified Al-0.1Zr and Al-0.1Zr-0.1Ti (at.%) alloys aged isothermally at 500 °C or aged isochronally in the range 300-600 °C. Titanium additions delay neither coarsening of the metastable L12 precipitates nor their transformation to the D023 structure. Both alloys overage at the same rate at or above 500 °C, during which spheroidal L12 precipitates transform to disk-shaped D023 precipitates at ca. 200 nm in diameter and 50 nm in thickness, exhibiting a cube-on-cube orientation relationship with the α-Al matrix. The transformation occurs heterogeneously on dislocations because of a large lattice parameter mismatch of the D023 phase with α-Al. The transformation is very sluggish and even at 575 °C coherent L12 precipitates can remain untransformed. Mechanisms of microstructural coarsening and strengthening are discussed with respect to the micrometer-scale dendritic distribution of precipitates.

KW - Aluminum alloys

KW - Coarsening

KW - Precipitation strengthening

KW - Titanium

KW - Zirconium

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U2 - 10.1016/j.actamat.2007.11.011

DO - 10.1016/j.actamat.2007.11.011

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AN - SCOPUS:40449101349

VL - 56

SP - 1182

EP - 1195

JO - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

IS - 6

ER -

Precipitation evolution in Al-Zr and Al-Zr-Ti alloys during aging at 450-600 °C

Abstract

Keywords

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