Effects of Dislocation Substructure on Creep Deformation Behavior in 0.2%C-9%Cr Steel

Mikami, Masato

doi:10.2355/isijinternational.isijint-2016-203

Cited by 8 publications

(9 citation statements)

References 31 publications

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“…Fine M 23 C 6 is also effective in this respect, by slowing down the recovery of dislocation structure while its coarsening during creep results in acceleration of creep deformation [35]. This is also consistent with Mikami [36] who reported a condensation and coarsening of precipitates accelerating the degradation. The increase in creep resistance due to fine Fe 2 M has been reported by Igarashi [37].…”

Section: Precipitate Strengtheningsupporting

confidence: 83%

Creep-resistant aeroengine shaft steels: Precipitates and consequences

Huang

2019

Materials Science and Technology

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Creep resistant steels must be stable over long periods of time under severe operating conditions. This paper reviews precipitation in Cr-Mo steels and maraging steels destined for elevated temperature applications. It also covers aspects of structural evolution, strengthening and degradation, all of which are essential for alloy design. Two classes of steels are emphasised, those with origins in the power generation industries, and a novel approach based on intermetallic precipitates.

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Section: Precipitate Strengtheningsupporting

confidence: 83%

Creep-resistant aeroengine shaft steels: Precipitates and consequences

Huang

2019

Materials Science and Technology

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“…The average lath misorientation (θ) remained at about 2.7 ± 0.2 deg from creep up to rupture (Figure 7, Table 2). related processes because new low-angle boundaries have dislocation origins [36]. But the EBSD and TEM results were in contrast to each other: the strong reduction in dislocation density occurred before the significant increase in the fraction of the LABs with 𝜃 ranging from 2 to 5 deg (Figure 8).…”

mentioning

confidence: 89%

“…This indicated that most fine particles were retained along the LABs up to rupture. Moreover, the fraction of the large carbides At the primary creep stage, the reduction of dislocation density occurred due to the annihilation and rearrangement into dislocation walls [11,35,36]. The lath widening should lead to the decrease in the fraction of the LABs.…”

Section: • Evolution Of Secondary Phase Particlesmentioning

confidence: 99%

“…Notably, the increase in the fraction of the LABs with θ ranging from 2 to 5 deg had non-monotonic behavior: at the end of the primary creep stage, the fraction of these LABs increased by 12.9% compared to the tempered state; then, during the steady-state creep stage, their fraction was slightly decreased by 6.3%; further, during the transition from the steady-state creep stage to the tertiary creep stage, the remarkable increment in the fraction of such LABs by 52% was revealed; and finally, the fraction of such LABs was decreased again in the ruptured state (Figure 7). The reduction in dislocation density within the lath interior and increase in the fraction of the LABs were considered to be related processes because new low-angle boundaries have dislocation origins [36]. But the EBSD and TEM results were in contrast to each other: the strong reduction in dislocation density occurred before the significant increase in the fraction of the LABs with θ ranging from 2 to 5 deg (Figure 8).…”

mentioning

confidence: 99%

“…In our opinion, the evolution of both dislocations and LABs could be described as follows. At the primary creep stage, the reduction of dislocation density occurred due to the annihilation and rearrangement into dislocation walls [11,35,36]. The lath widening should lead to the decrease in the fraction of the LABs.…”

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confidence: 99%

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Microstructural Evolution of a Re-Containing 10% Cr-3Co-3W Steel during Creep at Elevated Temperature

Fedoseeva,

Brazhnikov,

Degtyareva

et al. 2023

Metals

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Ten percent Cr steels are considered to be prospective materials for the production of pipes, tubes, and blades in coal-fired power plants, which are able to operate within ultra-supercritical steam parameters. The microstructural evolution of a Re-containing 10% Cr-3Co-3W steel with low N and high B content during creep was investigated at different strains at 923 K and under an applied stress of 120 MPa using TEM and EBSD analyses. The studied steel had been previously normalized at 1323 K and tempered at 1043 K for 3 h. In the initial state, the tempered martensite lath structure with high dislocation density was stabilized by M23C6 carbides, NbX carbonitrides, and M6C carbides. At the end of the primary creep stage, the main microstructural change was found to be the precipitation of the fine Laves phase particles along the boundaries of the prior austenite grains, packets, blocks, and martensitic laths. The remarkable microstructural degradation processes, such as the significant growth of martensitic laths, the reduction in dislocation density within the lath interiors, and the growth of the grain boundary Laves phase particles, occurred during the steady-state and tertiary creep stages. Moreover, during the steady-state creep stage, the precipitation of the V-rich phase was revealed. Softening was in accordance with the dramatic reduction in hardness during the transition from the primary creep stage to the steady-state creep stage. The reasons for the softening were considered to be due to the change in the strengthening mechanisms and the interactions of the grain boundary M23C6 carbides and Laves phase with the low-angle boundaries of the martensitic laths and free dislocations.

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