Microstructural Observations on Oxidized Ni-Based Superalloy TMS-75 and PGM-Doped Derivatives

Pruessner, K.; Harada, Hiroshi

doi:10.1149/1.3482074

Cited by 6 publications

(5 citation statements)

References 42 publications

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“…[23] These oxide morphologies observed in Figure 3 are comparable with other Ni-base superalloys, and more characterizations of the oxides were reported. [1,2,[23][24][25][26] Some alloys in group A, for example ''Alloy B'' in Figure 3(b), also partially formed a NiO layer; however, the thickness and area fraction of the NiO layer in these alloys is far less than those in group B. In fact, group B alloys showed more than 0.5 mg/cm 2 of an observed weight change after a onecycle oxidation test.…”

Section: Resultssupporting

confidence: 82%

A New Oxide Morphology Map: Initial Oxidation Behavior of Ni-Base Single-Crystal Superalloys

Suzuki

Kawagishi

Yokokawa

et al. 2011

Metall Mater Trans A

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Predictions for oxidation behavior of Ni-base superalloys become more difficult than before because of the complex alloy composition. In this study, we focus on the initial oxidation behavior of Ni-base superalloys, and we suggest a new diagram to predict the initial oxide morphology of Ni-base superalloys with 63 binary, ternary, and multicomponent Ni-base single-crystal superalloys at 1373 K (1100°C). As a comparison of observed and calculated weight changes after one cycle at 1373 K (1100°C) obtained by a regression analysis, 63 alloys demonstrated two distinct behaviors, which are divided heretofore into group A and group B. Microstructural observation revealed that an oxide layer in the group A alloys consists of Al 2 O 3 and/or spinel or complex oxide, whereas an oxide layer in the group B alloys consists of a thick NiO layer with an Al 2 O 3 internal subscale. Thermodynamic properties can reflect more effects of alloy elements in Ni-base superalloys, and Al and Cr activities, calculated by Thermo-Calc, were used as factors to predict initial oxidation morphology. Groups A and B alloys can clearly be divided according to Al and Cr activities. This was suggested as a new diagram to predict the initial oxide morphology of Ni-base superalloys, and possibly it can apply for any generation of Ni-base superalloys.

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Section: Resultssupporting

confidence: 82%

A New Oxide Morphology Map: Initial Oxidation Behavior of Ni-Base Single-Crystal Superalloys

Suzuki

Kawagishi

Yokokawa

et al. 2011

Metall Mater Trans A

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“…The internal subscale oxide layer formed when oxygen from the atmosphere diffused through the NiO scale. The similar morphology was reported by Pruessner in a third generation Nibase single crystal superalloy, TMS-75[20]. These oxide morphologies observed in Figure2are comparable with other Ni-…”

supporting

confidence: 88%

“…""#$%) *+#,-%! *+#,-%) base superalloys, and more characterizations of the oxides were reported [14,20,21]. Some alloys in group A, e.g.…”

Section: Relationships Between Observed Calculated Weight Gains and T...mentioning

confidence: 99%

Prediction of Initial Oxidation Behavior of Ni‐Base Single Crystal Superalloys: A New Oxidation Map and Regression Analysis

et al. 2012

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“…A dense, slow-growing and well-adherent alumina scale has been reported to develop on René N5 following high temperature (~1000˚C) oxidation [82,83,84]. A summary of the oxides formed on René N5 for different heat treatment temperatures and times are outlined in Table 5, where numbered items indicate the sequence of oxides (1=adjacent to substrate).…”

Section: René N5 247mentioning

confidence: 99%

“…The YSZ adheres well to this layer and adhesion is improved with the addition of REs [63]. However, α-Al 2 O 3 scales are known to develop on oxidized nickel-based superalloy substrate materials as well; such as IN-738, CMSX-4 and René N5 [79,80,81,82,83,84]. Theoretically, if an α-Al 2 O 3 scale were formed directly on a nickelbased superalloy than a YSZ should be able to adhere directly to the substrate material itself.…”

Section: René N5 247mentioning

confidence: 99%

Effect of Pre-Oxidation and Thermal Exposure on the Microstructure of Superalloys and Thermal Barrier Coating Systems

Walker¹

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Thermal barrier coatings (TBCs) enable the nickel-base superalloy gas turbine blades of modern gas turbine engines to run at their highest possible temperatures. Currently, a bond coat (BC) is utilized to adhere the yttria-stabilized zirconia (YSZ) top coat to the nickel-base superalloy substrate. However, the addition of this manufacturing step increases cost. In this study, three nickel-based superalloys: IN-738, CMSX-4 and Rene N5 are considered. Isothermal oxidation studies were conducted at 1150°C in atmosphere for holding times ranging from 30 minutes to 16 hours. YSZ top coats were applied directly to the nickel-base superalloy René N5 isothermally oxidized for 2hrs at 1150°C in atmosphere. Rene N5 oxidized at this time and temperature produced the most adherent, dense and uniform α-Al 2 O 3 scale which was anticipated to enhance YSZ adhesion. YSZ coatings were then applied using suspension plasma spraying technology (SPS). Coatings of dense vertically cracked (DVC) and columnar morphologies were applied. Following YSZ application, the samples were subjected to a diffusion heat treatment in vacuum at 1080°C to promote YSZ/substrate adhesion. These samples were then cyclically and isothermally tested in atmosphere at 1150°C. Both SPS DVC and SPS Columnar coatings were found to have poor adhesion (delaminated in less than 25 cycles). The lack of adequate α-Al 2 O 3 coverage, the rapid formation of spinel and grit blasting prior to coating deposition were determined to be the primary causes of poor performance.

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Microstructural Observations on Oxidized Ni-Based Superalloy TMS-75 and PGM-Doped Derivatives

Cited by 6 publications

References 42 publications

A New Oxide Morphology Map: Initial Oxidation Behavior of Ni-Base Single-Crystal Superalloys

A New Oxide Morphology Map: Initial Oxidation Behavior of Ni-Base Single-Crystal Superalloys

Prediction of Initial Oxidation Behavior of Ni‐Base Single Crystal Superalloys: A New Oxidation Map and Regression Analysis

Effect of Pre-Oxidation and Thermal Exposure on the Microstructure of Superalloys and Thermal Barrier Coating Systems

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