AFM, SEM AND TEM study of damage mechanisms in cyclically strained mar-M247 at room temperature and high temperatures

Šulák, Ivo; Obrtlík, Karel

doi:10.1016/j.tafmec.2020.102606

Cited by 24 publications

(15 citation statements)

References 65 publications

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“…Softening is presumably promoted by the localization of cyclic plastic strain in PSBs and by shearing of γ 0 precipitates in agreement with numerous studies on high-temperature deformation of Ni-based superalloys. 3,5,11,32 This corresponds to the observation of dislocation bands of various thicknesses (Figure 13B,C) and finally also to the appearance of PSMs on the specimen surface (Figure 11). The cyclic stressstrain response of René 41 at 800 C is different from many other wrought alloys which often exhibit initial cyclic hardening at comparably high temperatures (e.g., Waspaloy, 14 GH4742 16 or 718 Plus 9 ).…”

Section: Cyclic Deformation Behavior At 800 Csupporting

confidence: 53%

“…36 Softening behavior has been assigned to the localization of cyclic slip in PSBs (Figure 11) and the shearing of γ 0 precipitates (Figure 13), in agreement with numerous studies on high-temperature deformation of Ni-based superalloys. 3,5,11,32,37 The comparison with room temperature shows that cyclic deformation at 800 C is more homogeneous. It is manifested in frequent shearing of γ 0 precipitates (Figure 13) and a lower tendency to form slip bands (Figure 13A).…”

Section: Cyclic Deformation Behavior At 800 Cmentioning

confidence: 99%

“…This process has been documented for superalloys. 9,11,12,16,19 Fatigue cracks start mostly from PSMs (see the statistics in Figure 14). Multiple fatigue crack initiation occurred, and the fracture surfaces were dimple-like, indicating transgranular fatigue crack propagation, typical for superalloys at room temperature.…”

Section: Fatigue Damage and Fatigue Life At Room Temperaturementioning

confidence: 99%

“…Further studies [6][7][8] yielded further information on the behavior of various types of fatigued nickel-base superalloys. In recent years, attention has been concentrated on the stress response, 9 the details of the interaction of slip bands with precipitates, 10 and the mechanism of PSMs formation and crack initiation 11,12 at ambient and elevated temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…Both these phenomena depend on cyclic strain localization. 18 Recent studies of cyclic strain localization in polycrystalline superalloys 11,12,19 revealed basic information on the importance of cyclic slip localization in the initiation of fatigue cracks in room temperature cyclic loading. Information concerning high temperatures is sometimes contradictory.…”

Section: Introductionmentioning

confidence: 99%

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Importance of γ′ shearing in low‐cycle fatigue of a wrought superalloy

Babinský,

Poczklán,

Gálíková

et al. 2024

Fatigue Fract Eng Mat Struct

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The present study deals with the fatigue behavior of a wrought nickel‐based superalloy René 41. Uniaxial, fully reversed low‐cycle fatigue tests were conducted at room and elevated (800°C) temperatures under total strain control. Cyclic response was analyzed using the statistical theory of the hysteresis loop, and scanning and transmission electron microscopies were employed to study relevant damage mechanisms. At room temperature, cyclic deformation was found to localize to slip bands since the first cycle, and most slip bands were formed very early in the fatigue life. Hence, shearing of the strengthening phase, coherent γ′ precipitates, was found to be significant only in the first few cycles. At 800°C, fatigue life was affected by an environmental attack resulting in a surface oxide layer. Cyclic deformation was less localized; nevertheless, cyclic slip localization in persistent slip bands and resulting γ′ shearing contributed to cyclic softening throughout the fatigue life.

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Section: Cyclic Deformation Behavior At 800 Csupporting

confidence: 53%

Section: Cyclic Deformation Behavior At 800 Cmentioning

confidence: 99%

Section: Fatigue Damage and Fatigue Life At Room Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Importance of γ′ shearing in low‐cycle fatigue of a wrought superalloy

Babinský,

Poczklán,

Gálíková

et al. 2024

Fatigue Fract Eng Mat Struct

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Eddy Current Testing in the Quantitive Assessment of Degradation State in MAR247 Nickel Superalloy with Aluminide Coatings

Tytko,

Adamczyk-Habrajska,

Luo

et al. 2024

J Nondestruct Eval

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In this paper, the effectiveness of the eddy current methodology for crack detection in MAR 247 nickel-based superalloy with aluminide coatings subjected to cyclic loading was investigated. The specimens were subjected to force-controlled fatigue tests under zero mean level, constant stress amplitude from 300 MPa to 600 MPa and a frequency of 20 Hz. During the fatigue, a particular level of damage was introduced into the material leading to the formation of microcracks. Subsequently, a new design of probe with a pot core was developed to limit magnetic flux leakage and directed it towards the surface under examination. The suitability of the new methodology was further confirmed as the specimens containing defects were successfully identified. The changes in probe resistance values registered for damaged specimens ranged approximately from 8 to 14%.

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