Development of a New Cast and Wrought Alloy (Rene 65) for High Temperature Disk Applications

Heaney, J.; Powell, A.; Bond, B.; O'Brien, C.; Lasonde, Michael L.

doi:10.7449/2014/superalloys_2014_67_77

Cited by 23 publications

(14 citation statements)

References 3 publications

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“…René 65 TM is a commercial polycrystalline γ-γ' nickel based superalloy, which nominal composition in wt% is 13 Cr-16 Co-3.7 Ti-2.1 Al-4 Mo-4 W-1 Fe-0.7 Nb-0.05 Zr, 0.016 B, balance Ni [31]. Double-cone shaped samples were withdrawn from an industrially forged piece.…”

Section: Materials and Experimental Setupmentioning

confidence: 99%

Heteroepitaxial recrystallization: A new mechanism discovered in a polycrystalline γ-γ′ nickel based superalloy

Charpagne

Billot

Franchet

et al. 2016

Journal of Alloys and Compounds

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International audienceThe dynamic recrystallization mechanisms and kinetics of a recently developed γ-γ′ nickel based superalloy are studied at different subsolvus temperatures. Special care is paid to the evolution of γ′ particles and their influence on recrystallization phenomena. An original dynamic recrystallization mechanism is highlighted thanks to the combined use of Energy Dispersive Spectrometry and Electron BackScattered Diffraction mapping techniques. This mechanism leads to the formation of large heteroepitaxial pairs, made of a primary precipitate embedded in a recrystallized grain having the same crystallographic orientation. Recrystallization nuclei arise from inverse precipitation of γ phase at the rim of primary γ′ precipitates, prior to deformation. This heteroepitaxial recrystallization mechanism is reported here for the first time. It controls dynamic microstructure evolution at low strains and is then progressively replaced by the conventional discontinuous necklace recrystallization process at higher strains

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Section: Materials and Experimental Setupmentioning

confidence: 99%

Heteroepitaxial recrystallization: A new mechanism discovered in a polycrystalline γ-γ′ nickel based superalloy

Charpagne

Billot

Franchet

et al. 2016

Journal of Alloys and Compounds

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“…René 65 TM is a γ–γ’ polycrystalline nickel‐based superalloy that has been derivated from the René 88 TM PM alloy for allowing the casting and forging processing route (Heaney et al ., ). γ–γ’ nickel‐based superalloys are basically composed of a γ matrix (FCC solid solution) and second‐phase γ’ precipitates adopting a L1 2 crystal structure.…”

Section: Introductionmentioning

confidence: 97%

Evidence of multimicrometric coherent γ′ precipitates in a hot‐forged γ–γ′ nickel‐based superalloy

Charpagne

Vennéguès

Billot

et al. 2016

Journal of Microscopy

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This paper demonstrates the existence of large γ' precipitates (several micrometres in diameter) that are coherent with their surrounding matrix grain in a commercial γ-γ' nickel-based superalloy. The use of combined energy dispersive X-ray spectrometry and electron backscattered diffraction (EBSD) analyses allowed for revealing that surprising feature, which was then confirmed by transmission electron microscopy (TEM). Coherency for such large second-phase particles is supported by a very low crystal lattice misfit between the two phases, which was confirmed thanks to X-ray diffractograms and TEM selected area electron diffraction patterns. Dynamic recrystallization of polycrystalline γ-γ' nickel-based superalloys has been extensively studied in terms of mechanisms and kinetics. As in many materials with low stacking fault energy, under forging conditions, the main softening mechanism is discontinuous dynamic recrystallization. This mechanism occurs with preferential nucleation on the grain boundaries of the deformed matrix. The latter is then being consumed by the growth of the newly formed grains of low energy and by nucleation that keeps generating new grains. In the case of sub-solvus forging, large γ' particles usually pin the migrating boundaries and thus limit grain growth to a size which is determined by the distribution of second-phase particles, in good agreement with the Smith-Zener model. Under particular circumstances, the driving force associated with the difference in stored energy between the growing grains and the matrix can be large enough that the pinning forces can be overcome, and some grains can then reach much larger grain sizes. In the latter exceptional case, some intragranular primary γ' particles can be observed, although they are almost exclusively located on grain boundaries and triple junctions otherwise. In both cases, primary precipitates have no special orientation relationship with the surrounding matrix grain(s). This paper demonstrates the existence of high fractions of large γ' precipitate (several micrometres in diameter) that are coherent with their surrounding matrix grain, in a commercial γ-γ' nickel-based superalloy. Such a configuration is very surprising, because there is apparently no reason for the coherency of such particles.

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“…a, with dimensions following ASTM E1820. The material was a Nickel superalloy with yield strength of 1213 MPa (176 ksi) at 0.2% offset, Young's modulus of 219.9 GPa (31.9 Msi), Poisson's ratio of 0.3 and density of 27 680 kg m −3 (14.15 lb/in 3 ) . Prior to fatigue crack experiments, a similar setup was used in accordance to ASTM E1820 to grow pre‐cracks of approximately 60 mils (1.52 mm), which were monitored using the DIC system with a field of view (FOV) of 10 × 8 mm (393.70 × 314.96 mils).…”

Section: Methodsmentioning

confidence: 99%

Validation of a cyclic plasticity computational method using fatigue full‐field deformation measurements

Cuadra

Baxevanakis

Loghin

et al. 2016

Fatigue Fract Eng Mat Struct

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The evolution of crack tip displacement and strain fields during uniaxial, room temperature, low‐cycle fatigue experiments of Nickel superalloy compact tension specimens was measured by a digital image correlation approach and was further used to validate a cyclic plasticity model and corresponding deformation calculations made by a finite elements methodology. The experimental results provided data trends for the opening displacements and near crack tip strains as function of cycles. A finite element model was developed to capture test conditions for a measured crack size. The model captures crack tip plasticity by using a constitutive model calibrated against stress‐strain measurements performed on a round bar. Similar quantities were extracted from the model predictions to compare with the digital image correlation measurements for model validation purposes. This type of direct comparison demonstrated that the computational model was capable to adequately capture the crack opening displacements at various stages of the specimen's fatigue life, providing in this way a tool for quantitative cyclic plasticity model validation. In addition, this integrated experimental‐computational approach provides a framework to accelerate our understanding related to interactions of fatigue test data and models, as well as ways to inform one another.

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Development of a New Cast and Wrought Alloy (Rene 65) for High Temperature Disk Applications

Cited by 23 publications

References 3 publications

Heteroepitaxial recrystallization: A new mechanism discovered in a polycrystalline γ-γ′ nickel based superalloy

Heteroepitaxial recrystallization: A new mechanism discovered in a polycrystalline γ-γ′ nickel based superalloy

Evidence of multimicrometric coherent γ′ precipitates in a hot‐forged γ–γ′ nickel‐based superalloy

Validation of a cyclic plasticity computational method using fatigue full‐field deformation measurements

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