Influence of Excess Volumes Induced by Re and W on Dislocation Motion and Creep in Ni-Base Single Crystal Superalloys: A 3D Discrete Dislocation Dynamics Study

Gao, Siwen; Yang, Zerong; Grabowski, Maximilian; Rogal, Jutta; Drautz, Ralf; Hartmaier, Alexander

doi:10.3390/met9060637

Cited by 9 publications

(3 citation statements)

References 70 publications

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“…This precaution is needed in order to prevent artifacts due to a source activation stress operating within the γ channel which may be superior to the dominant threshold stress for dislocation bowing out in the channel. Actually, this treatment follows other DDD simulation by Gao et al [56]. For all models, the initial dislocation density is set to 1.4 × 10 13 m −2 [38].…”

Section: Scnbss Modelsmentioning

confidence: 99%

An efficient algorithm of dislocation-precipitate interactions for single crystal nickel-based superalloys within discrete dislocation dynamics and its application

Huang¹,

Huang²

2021

Modelling Simul. Mater. Sci. Eng.

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In this paper, the discrete dislocation dynamics (DDD) framework for single crystal nickel-based superalloys (SCNBSs) modeling is extended to simulate the superdislocation pairs shearing numerous precipitates more efficiently. An adaptive dislocation segment meshing scheme by specially treating the dislocation segments deposited on the γ/γ′ interfaces is also used to decrease the computational expense. In addition, the MPI parallel algorithm is also realized to increase the computational speed. Through this DDD framework, the size-related plastic response of SCNBSs microcrystal containing collections of precipitates is systematically investigated. Two types of SCNBSs microcrystal samples, one with intact precipitates and the other with partial precipitates truncated by free surfaces, are established for different sample sizes. The influence of the sample size, two types of boundary, and the coherency stress induced by lattice mismatch between the two phases are discussed. The results show that the influence of sample size on the yield strength and the dispersity of stress–strain curves are relatively weak when more than four precipitates across the cross section. And the effect of sample size on deformation mode and the dislocation density is still evident for all the considered sample sizes. For two types (intact and truncated precipitates) of SCNBSs microcrystal samples, the remarkable difference in their mechanical responses and dislocation evolution appears when there is only one precipitate across the cross section. In addition, the misfit stress can significantly change the dislocation distribution in different channels. However, it has less influence on the tensile stress–strain response for the considered tensile loading condition. Our results indicate that to properly characterize the global mechanical behavior of bulk SCNBSs by micro-test, the microcrystal sample should present more than sixteen whole precipitates across the cross section.

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Section: Scnbss Modelsmentioning

confidence: 99%

An efficient algorithm of dislocation-precipitate interactions for single crystal nickel-based superalloys within discrete dislocation dynamics and its application

Huang¹,

Huang²

2021

Modelling Simul. Mater. Sci. Eng.

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“…In the gamma prime-containing Ni-base superalloys, the creep resistance at high temperature is also affected by the presence of solute atoms in solid solution. In their paper, Gao et al [13], by three-dimensional (3D) discrete dislocation dynamics simulations, proved that solute atoms such as Re and W affect dislocation glide and climb differently, and thus the back stress on dislocation motion. The different effects of these elements and their concentration as solute atoms on creep deformation resistance have also been proven.…”

Section: Creep-microstructure Correlations For Specific Materials Classesmentioning

confidence: 99%

Creep and High-Temperature Deformation of Metals and Alloys

Gariboldi

Spigarelli

2019

Metals

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“…In this work, the complex rafted microstructures obtained from PF simulations [17][18][19] are introduced into our previously developed comprehensive 3D DDD model [47,49] to clarify the influence of N-type rafting and P-type rafting on the creep behavior at the primary and secondary stage. The evolution of microstructure and dislocation during creep happens simultaneously in the real case.…”

Section: Introductionmentioning

confidence: 99%

Influence of rafted microstructures on creep in Ni-base single crystal superalloys: a 3D discrete dislocation dynamics study

Gao

Ali

Hartmaier

2019

Modelling Simul. Mater. Sci. Eng.

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Ni-base single-crystal superalloys exhibit a dynamic evolution of their microstructure during operation at elevated temperatures. The rafting of γ′ precipitates changes the mechanical behavior in a way that was understood insufficiently. In this work, we combine a phase-field method with a discrete dislocation dynamics model to clarify the influence of different rafted microstructures with the same initial dislocation density and configuration on creep behavior. The unrafted and rafted microstructures of Ni-base single crystal superalloys are simulated by a phase-field crystal plasticity method. By introducing these microstructures into a 3D discrete dislocation dynamics (DDD) model, the creep behavior under uniaxial loads of 350 and 250 MPa along [100] direction at 950 °C is studied. Due to the negative lattice mismatch of Ni-base superalloys, the N-type rafting with the formation of plate-like γ′ precipitates occurs under uniaxial tensile loads along {100} direction at high temperatures, while the P-type rafting with the formation of rod-like γ′ precipitates occurs under compressive loads. Taking the cuboidal, N-type rafted and P-type rafted microstructures as the initial and fixed microstructures for the same loading conditions, it is found from DDD simulations that the rafted microstructures result in smaller creep deformation than the cuboidal microstructure. The reason for this is that the coalescence of γ′ precipitates during the rafting diminishes the width of some γ channels, so as to increase the local Orowan stresses which retard the dislocation glide. For tensile loads, the N-type rafted microstructure has the best creep resistance. For a low compressive load, the P-type rafting shows a better creep resistance than N-type rafting.

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Influence of Excess Volumes Induced by Re and W on Dislocation Motion and Creep in Ni-Base Single Crystal Superalloys: A 3D Discrete Dislocation Dynamics Study

Cited by 9 publications

References 70 publications

An efficient algorithm of dislocation-precipitate interactions for single crystal nickel-based superalloys within discrete dislocation dynamics and its application

An efficient algorithm of dislocation-precipitate interactions for single crystal nickel-based superalloys within discrete dislocation dynamics and its application

Creep and High-Temperature Deformation of Metals and Alloys

Influence of rafted microstructures on creep in Ni-base single crystal superalloys: a 3D discrete dislocation dynamics study

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