Analytical electron-microscopy study of the breakdown of α-Al2O3 scales formed on oxide dispersion-strengthened alloys

B. A. Pint; A. J. Garratt-Reed; L. W. Hobbs

doi:10.1023/a:1010347504052

Analytical electron-microscopy study of the breakdown of α-Al₂O₃ scales formed on oxide dispersion-strengthened alloys

B. A. Pint, A. J. Garratt-Reed, L. W. Hobbs

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

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Abstract

Alumina scales formed during cyclic oxidation at 1200°C on three Y₂O₃-Al₂O₃-dispersed alloys: Ni₃Al, β-NiAl, and FeCrAl (Inco alloy MA956) were characterized. In each case, the Y₂O₃ dispersion improved the α-Al₂O₃ scale adhesion, but in the case of Ni₃Al, an external Ni-rich oxide spalled and regrew, indicating a less-adherent scale. A scanning-transmission electron microscope (STEM) analysis of the scale near the metal-scale interface revealed that the scale formed an ODS FeCrAl showed no base metal-oxide formation. However, the scale formed on ODS Ni₃Al showed evidence of cracking and Ni-rich oxides were observed. The microstructures and mechanisms discussed may be relevant to a thermal-barrier coating with an Al-depleted aluminide bond coat nearing failure.

Original language	English
Pages (from-to)	119-145
Number of pages	27
Journal	Oxidation of Metals
Volume	56
Issue number	1-2
DOIs	https://doi.org/10.1023/a:1010347504052
State	Published - 2001

Keywords

Adhesion
AlO
High-temperature oxidation
ODS alloys
Reactive-element effect

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title = "Analytical electron-microscopy study of the breakdown of α-Al2O3 scales formed on oxide dispersion-strengthened alloys",

abstract = "Alumina scales formed during cyclic oxidation at 1200°C on three Y2O3-Al2O3-dispersed alloys: Ni3Al, β-NiAl, and FeCrAl (Inco alloy MA956) were characterized. In each case, the Y2O3 dispersion improved the α-Al2O3 scale adhesion, but in the case of Ni3Al, an external Ni-rich oxide spalled and regrew, indicating a less-adherent scale. A scanning-transmission electron microscope (STEM) analysis of the scale near the metal-scale interface revealed that the scale formed an ODS FeCrAl showed no base metal-oxide formation. However, the scale formed on ODS Ni3Al showed evidence of cracking and Ni-rich oxides were observed. The microstructures and mechanisms discussed may be relevant to a thermal-barrier coating with an Al-depleted aluminide bond coat nearing failure.",

keywords = "Adhesion, AlO, High-temperature oxidation, ODS alloys, Reactive-element effect",

author = "Pint, \{B. A.\} and Garratt-Reed, \{A. J.\} and Hobbs, \{L. W.\}",

year = "2001",

doi = "10.1023/a:1010347504052",

language = "English",

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pages = "119--145",

journal = "Oxidation of Metals",

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T1 - Analytical electron-microscopy study of the breakdown of α-Al2O3 scales formed on oxide dispersion-strengthened alloys

AU - Pint, B. A.

AU - Garratt-Reed, A. J.

AU - Hobbs, L. W.

PY - 2001

Y1 - 2001

N2 - Alumina scales formed during cyclic oxidation at 1200°C on three Y2O3-Al2O3-dispersed alloys: Ni3Al, β-NiAl, and FeCrAl (Inco alloy MA956) were characterized. In each case, the Y2O3 dispersion improved the α-Al2O3 scale adhesion, but in the case of Ni3Al, an external Ni-rich oxide spalled and regrew, indicating a less-adherent scale. A scanning-transmission electron microscope (STEM) analysis of the scale near the metal-scale interface revealed that the scale formed an ODS FeCrAl showed no base metal-oxide formation. However, the scale formed on ODS Ni3Al showed evidence of cracking and Ni-rich oxides were observed. The microstructures and mechanisms discussed may be relevant to a thermal-barrier coating with an Al-depleted aluminide bond coat nearing failure.

AB - Alumina scales formed during cyclic oxidation at 1200°C on three Y2O3-Al2O3-dispersed alloys: Ni3Al, β-NiAl, and FeCrAl (Inco alloy MA956) were characterized. In each case, the Y2O3 dispersion improved the α-Al2O3 scale adhesion, but in the case of Ni3Al, an external Ni-rich oxide spalled and regrew, indicating a less-adherent scale. A scanning-transmission electron microscope (STEM) analysis of the scale near the metal-scale interface revealed that the scale formed an ODS FeCrAl showed no base metal-oxide formation. However, the scale formed on ODS Ni3Al showed evidence of cracking and Ni-rich oxides were observed. The microstructures and mechanisms discussed may be relevant to a thermal-barrier coating with an Al-depleted aluminide bond coat nearing failure.

KW - Adhesion

KW - AlO

KW - High-temperature oxidation

KW - ODS alloys

KW - Reactive-element effect

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U2 - 10.1023/a:1010347504052

DO - 10.1023/a:1010347504052

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JO - Oxidation of Metals

JF - Oxidation of Metals

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ER -

Analytical electron-microscopy study of the breakdown of α-Al₂O₃ scales formed on oxide dispersion-strengthened alloys

Abstract

Keywords

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