Investigating the Dislocation-Driven Micro-mechanical Response Under Non-isothermal Creep Conditions in Single-Crystal Superalloys

Schwalbe, Caspar; Cormier, Jonathan; Jones, C.N.; Galindo-Nava, E.I.; Rae, C.M.F.

doi:10.1007/s11661-018-4764-3

Cited by 15 publications

(2 citation statements)

References 43 publications

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“…Tensile creep tests were performed in air using a Setra SF 2400 in-house-customized creep testing frame equipped with a radiant heating furnace [29,30]. The temperature of a specimen was controlled within 1250 ± 2 • C by a Eurotherm 2408 temperature controller (Eurotherm Ltd., Worthing, UK) connected to an S-type thermocouple spot-welded in the middle of the gauge section, in accordance with TMF Code of Practice [31].…”

Section: Creep Testsmentioning

confidence: 99%

Ultra-High Temperature Creep of Ni-Based SX Superalloys at 1250 °C

Utada

Despres

Cormier

2021

Metals

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Very high temperature creep properties of twelve different Ni-based single crystal superalloys have been investigated at 1250 °C and under different initial applied stresses. The creep strength at this temperature is mainly controlled by the remaining γ′ volume fraction. Other parameters such as the γ′ precipitate after microstructure evolution and the γ/γ′ lattice parameter mismatch seem to affect the creep strength to a lesser degree in these conditions. The Norton Law creep exponent lies in the range 6–9 for most of the alloys studied, suggesting that dislocation glide and climb are the rate limiting deformation mechanisms. Damage mechanisms in these extreme conditions comprise creep strain accumulation leading to pronounced necking and to recrystallization in the most severely deformed sections of the specimens.

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Section: Creep Testsmentioning

confidence: 99%

Ultra-High Temperature Creep of Ni-Based SX Superalloys at 1250 °C

Utada

Despres

Cormier

2021

Metals

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“…Both the in-service and processing behaviour of single crystal nickel-base superalloys has been traditionally derived from isothermal stress-strain measurements, often performed under constant stress or constant strain rate [14,15,16,17]. The transient temperature regimes subjected to nickel-base superalloys during casting may be better represented by non-isothermal creep deformation experiments, where there is extensive data in the high temperature (up to ∼1200 • C), low stress condition in several alloy systems including CMSX4 [18,19], MC2 [20,21,22] & MC-NG [23,24]. In creep behaviour, capturing the thermo-mechanical history dependence of deformation and microstructure is known to be critical in predicting subsequent plasticity [25,26], which must also play a governing role in the behaviour of transient micromechanical and microstructural phenomena during an investment casting process.…”

Section: Introductionmentioning

confidence: 99%

Ultra high-temperature deformation in a single crystal superalloy: Meso-scale process simulation and micro-mechanisms

Tang¹,

D’Souza²,

Roebuck³

et al. 2020

Preprint

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A mesoscale study of a single crystal nickel-base superalloy subjected to an industrially relevant process simulation has revealed the complex interplay between microstructural development and the micromechanical behaviour. As sample gauge volumes were smaller than the length scale of the highly cored structure of the parent material from which they were produced, their subtle composition differences gave rise to differing work hardening rates, influenced by varying secondary dendrite arm spacings, γ phase solvus temperatures and a topologically inverted γ/γ microstructure. The γ precipitates possessed a characteristic 'X' morphology, resulting from the simultaneously active solute transport mechanisms of thermally favoured octodendritic growth and N-type rafting, indicating creep-type mechanisms were prevalent. High resolution-electron backscatter diffraction (HR-EBSD) characterisation reveals deformation patterning that follows the γ/γ microstructure, with high geometrically necessary dislocation density fields localised to the γ/γ interfaces; Orowan looping is evidently the mechanism that mediated plasticity. Examination of the residual elastic stresses indicated the 'X' γ precipitate morphology had significantly enhanced the deformation heterogeneity, resulting in stress states within the γ channels that favour slip, and that encourage further growth of γ precipitate protrusions. The combination of such localised plasticity and residual stresses are considered to be critical in the formation of the recrystallisation defect in subsequent post-casting homogenisation heat treatments.

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Evaluation and Comparison of Damage Accumulation Mechanisms During Non-isothermal Creep of Cast Ni-Based Superalloys

Antonov

Utada

et al. 2020

The Minerals, Metals &Amp; Materials Series

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Investigating the Dislocation-Driven Micro-mechanical Response Under Non-isothermal Creep Conditions in Single-Crystal Superalloys

Cited by 15 publications

References 43 publications

Ultra-High Temperature Creep of Ni-Based SX Superalloys at 1250 °C

Ultra-High Temperature Creep of Ni-Based SX Superalloys at 1250 °C

Ultra high-temperature deformation in a single crystal superalloy: Meso-scale process simulation and micro-mechanisms

Evaluation and Comparison of Damage Accumulation Mechanisms During Non-isothermal Creep of Cast Ni-Based Superalloys

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