Creep deformation related to dislocations cutting the γ′ phase of a Ni-base single crystal superalloy

Wang, X.G.; Liu, J.L.; Jin, Tao; Sun, Xiaofeng; Zhou, Yu; Hu, Z.Q.; Do, Jeonghyeon; Choi, Baig-Gyu; Kim, I.S.; Jo, Chang-Yong

doi:10.1016/j.msea.2014.12.060

Cited by 53 publications

(9 citation statements)

References 25 publications

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“…The accumulation of the different dislocation could promote the formation the network formation at the γ/γ′ interface. The present creep was conducted in the high temperatures and low stresses 43 , 44 . The dislocations glide is observed in the γ channel of the samples without the magnetic field (Fig.…”

Section: Resultsmentioning

confidence: 99%

Improvement in creep life of a nickel-based single-crystal superalloy via composition homogeneity on the multiscales by magnetic-field-assisted directional solidification

Ren

Niu

Ding

et al. 2018

Sci Rep

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The improvement of the creep properties of single-crystal superalloys is always strongly motivated by the vast growing demand from the aviation, aerospace, and gas engine. In this study, a static magnetic-field-assisted solidification process significantly improves the creep life of single-crystal superalloys. The mechanism originates from an increase in the composition homogeneity on the multiscales, which further decreases the lattice misfit of γ/γ′ phases and affects the phase precipitation. The phase-precipitation change is reflected as the decrease in the γ′ size and the contents of carbides and γ/γ′ eutectic, which can be further verified by the variation of the cracks number and raft thickness near the fracture surface. The variation of element partition decreases the dislocation quantity within the γ/γ′ phases of the samples during the crept deformation. Though the magnetic field in the study destroys the single-crystal integrity, it does not offset the benefits from the compositional homogeneity. The proposed means shows a great potential application in industry owing to its easy implement. The uncovered mechanism provides a guideline for controlling microstructures and mechanical properties of alloys with multiple components and multiple phases using a magnetic field.

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Section: Resultsmentioning

confidence: 99%

Improvement in creep life of a nickel-based single-crystal superalloy via composition homogeneity on the multiscales by magnetic-field-assisted directional solidification

Ren

Niu

Ding

et al. 2018

Sci Rep

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“…The formation mechanism of these dislocations is shown in the inset at the top right corner of Figure 5E. There may be a dislocation source (Wang et al, 2015), which constantly generates new dislocations in response to the stress, near the γ′ precipitates and when an accumulated number of dislocations is sufficient, the stress field generated by the blocked dislocations will push the former dislocations to cut into the γ′ precipitates and then generate a dislocation row. In addition, it is also worth noting that there are quite a few secondary γ′ precipitates observed in Figure 5F.…”

Section: The Behavior Of Dislocations and Stacking Faults At Point C ...mentioning

confidence: 99%

Microstructure degradation of service-exposed turbine blades made of directionally solidified DZ125 superalloy

et al. 2022

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The investigation about the degradation behavior of turbine blades exposed to complex and extreme environments for long-term service is of great importance to assess the remaining life of the blades. In our work, the microstructure at different positions of the service-exposed turbine blade was characterized from the micron scale to the nanoscale. The results showed that there are noticeable differences in the microstructure at different positions of the blade and the blade has a complex service history. These conclusions suggest that the most severely damaged part of the blade should be responsible for assessing the remaining life of the blade, moreover, the mechanical properties of materials should not be limited to life at constant temperature and stress, rather non-isothermal and variable stress tests are more instructive in assessing the performance or life of aircraft engine blade materials.

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“…where m is the mobile dislocation density, b is the magnitude of Burgers vectors, and v is the average velocity of the mobile dislocations. That is to say, the density, type and mobility of superdislocations in γʹ phase control the creep rates [25,37] [25,40]. Therefore, the formation of a[100] superdislocations in [001] and [011] specimens may be responsible for a low creep strain rate.…”

Section: Effects Of Microstructure and Dislocations On Stress Rupture Anisotropymentioning

confidence: 99%

“…Considering the deformation mechanism, both interfacial dislocation networks and superdislocations are observed in three oriented specimens, but the morphology of dislocation networks and type of superdislocations are distinct. The regular dislocation networks may enhance the creep resistance of [001] specimens [26], and the a[100] superdislocations with low mobility may be responsible for the low creep strain rate of [001] and [011] specimens [25,40]. Whereas, further work is required to quantitatively study the correlation between creep performance and interfacial dislocation spacings of different oriented specimens based on a unified scale.…”

Section: Effects Of Microstructure and Dislocations On Stress Rupture Anisotropymentioning

confidence: 99%

Anisotropic Stress Rupture Properties of a 3rd-Generation Nickel-Based Single-Crystal Superalloy at 1100 °C/150 MPa

Wang

Gong

et al. 2019

Acta Metall. Sin. (Engl. Lett.)

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The influence of orientation on the stress rupture behaviors of a 3rd-generation nickel-based single-crystal superalloy was investigated at 1100 °C/150 MPa. It is found that the stress rupture anisotropy is shown at 1100 °C, but not so obvious compared with that at intermediate temperatures. The [001] specimens display the longest rupture life, [111] specimens show the shortest rupture life, and [011] specimens exhibit the intermediate life. Detailed observations show that the final fracture is caused by crack initiation and propagation, and the anisotropy of three oriented specimens is related to the fracture modes, γ/γʹ microstructures, interfacial dislocation networks and cutting mechanisms in γʹ phase. For [001] specimens, N-type rafted structures are formed which can well hinder the slip and climb of dislocations. Besides, the regular interfacial dislocation networks can prevent dislocations from cutting into γʹ phase, leading to the improvement of the creep resistance. For [011] specimens, ± 45° rafted structures and irregular networks result in less strain hardening. For [111] specimens, a large number of crack propagation paths and inhomogeneous deformations caused by irregular rafted structures deteriorate the property and result in the shortest life. Furthermore, a[100] superdislocations with low mobility are widely formed in [001] and [011] specimens which suggests the low creep strain rate during steady creep stage, whereas superdislocations in [111] specimens possess high mobility, which indicates the high strain rate and corresponding poor stress rupture property.

show abstract

Creep deformation related to dislocations cutting the γ′ phase of a Ni-base single crystal superalloy

Cited by 53 publications

References 25 publications

Improvement in creep life of a nickel-based single-crystal superalloy via composition homogeneity on the multiscales by magnetic-field-assisted directional solidification

Improvement in creep life of a nickel-based single-crystal superalloy via composition homogeneity on the multiscales by magnetic-field-assisted directional solidification

Microstructure degradation of service-exposed turbine blades made of directionally solidified DZ125 superalloy

Anisotropic Stress Rupture Properties of a 3rd-Generation Nickel-Based Single-Crystal Superalloy at 1100 °C/150 MPa

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