A mechanism governing oxidation-assisted low-cycle fatigue of superalloys

Evans, A.G.; He, Ming; Suzuki, Akihito; Gigliotti, M. F. X.; Hazel, Brian; Pollock, Tresa M.

doi:10.1016/j.actamat.2009.02.047

Cited by 55 publications

(40 citation statements)

References 26 publications

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“…Nevertheless, this has led to high alloy density and a high propensity to form refractory oxides that degrade the surface stability [6][7][8][9][10]. The ability to maintain surface stability in oxidizing and corrosive environments is one of the most critical requirements for high temperature application materials, since material loss and surface degradation due to oxidation and corrosion can ultimately lead to the failure of structural components [11][12][13][14]. Recently, novel high temperature alloys based on the "high entropy alloy" concept have been designed by incorporating both sluggish diffusion and lattice distortion strengthening effects [15][16][17][18], and these materials have been referred to as "high entropy superalloys" (HESAs) [19]; this alloy design approach allows HESAs to be strengthened by high contents of various solutes rather than alloying with a high content of refractory elements.…”

Section: Introductionmentioning

confidence: 99%

High Temperature Oxidation and Corrosion Properties of High Entropy Superalloys

Tsao

Yeh

Kuo

et al. 2016

Entropy

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Abstract:The present work investigates the high temperature oxidation and corrosion behaviour of high entropy superalloys (HESA). A high content of various solutes in HESA leads to formation of complex oxides, however the Cr and Al activities of HESA are sufficient to promote protective chromia or alumina formation on the surface. By comparing the oxidation and corrosion resistances of a Ni-based superalloy-CM247LC, Al 2 O 3 -forming HESA can possess comparable oxidation resistance at 1100˝C, and Cr 2 O 3 -forming HESA can exhibit superior resistance against hot corrosion at 900˝C. This work has demonstrated the potential of HESA to maintain surface stability in oxidizing and corrosive environments.

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Section: Introductionmentioning

confidence: 99%

High Temperature Oxidation and Corrosion Properties of High Entropy Superalloys

Tsao

Yeh

Kuo

et al. 2016

Entropy

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“…Moreover, they must withstand the large mechanical loads necessary for efficient extraction of mechanical energy from the hot gas stream. Hence, creep [1,2] and fatigue [3,4] must be resisted. Recently, a new grade of single-crystal superalloy was developed for such applications, which displays a good balance of environmental and mechanical properties.…”

mentioning

confidence: 99%

On the Mechanical Behavior of a New Single-Crystal Superalloy for Industrial Gas Turbine Applications

Sato

Moverare

Hasselqvist

et al. 2012

Metall Mater Trans A

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“…Evans et al [3][4][5] examined the role of compressive growth strains of the α-Al 2 O 3 layer in extension of a crack in isothermal compressive cyclic loading using a finite element model, and predicted that the compressive stress of the α-Al 2 O 3 layer causes crack extension by inward extrusion of the α-Al 2 O 3 layer along the crack front during compressive loading. The predicted crack growth rate was close to the crack growth rate observed in the interrupted specimens.…”

Section: Crack Growth In Hold-time Lcf Of Single-crystal Ni-base Supementioning

confidence: 99%

Oxide-assisted crack growth in hold-time low-cycle-fatigue of single-crystal superalloys

Suzuki

Gao

Lipkin

et al. 2014

MATEC Web of Conferences

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Abstract.Compressive hold-time low-cycle fatigue is one of the important damage modes in Ni-based superalloy hot-gas path components. In strain controlled LCF, the compressive hold typically degrades fatigue life significantly due to creep relaxation and the resultant generation of tensile stress upon returning to zero strain. Crack initiation typically occurs on the surface, and therefore, the cracks are covered with layers of oxides. Recent finite element modeling based on experimental observations has indicated that the in-plane compressive stress in the alumina layer formed on the surface of the bond coat assists rumpling and, eventually, leads to initiation of cracks. The stress in the oxide layer continues to assist crack extension by pushing the alumina layer along the crack front during the compressive hold. In-situ measurements of the growth strains of alumina were performed using high energy synchrotron X-rays at Argonne National Lab. Specimens of single-crystal superalloys with and without aluminide coatings were statically pre-oxidized to form a layer of alumina at 1093 and 982• C. For the in-situ synchrotron measurements, the specimens were heated up to the pre-oxidation temperatures with a heater. The alumina layers on both bare and coated specimens show compressive in-plane strains at both temperatures. The oxide strains on the superalloys showed dependency on temperature; on the other hand, the oxide strains in the aluminide coatings were insensitive to temperature. The magnitude of the compressive strains was larger on the superalloys than the ones on the aluminide coatings.

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A mechanism governing oxidation-assisted low-cycle fatigue of superalloys

Cited by 55 publications

References 26 publications

High Temperature Oxidation and Corrosion Properties of High Entropy Superalloys

High Temperature Oxidation and Corrosion Properties of High Entropy Superalloys

On the Mechanical Behavior of a New Single-Crystal Superalloy for Industrial Gas Turbine Applications

Oxide-assisted crack growth in hold-time low-cycle-fatigue of single-crystal superalloys

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