Effect of Alloying on the Nucleation and Growth of Laves Phase in the 9–10%Cr-3%Co Martensitic Steels during Creep

Published on Dec 30, 2020
· DOI :10.3390/MET11010060
Alexandra Fedoseeva10
Estimated H-index: 10
,
Ivan Nikitin2
Estimated H-index: 2
+ 3 AuthorsRustam Kaibyshev58
Estimated H-index: 58
Source
Abstract
References49
Newest
#1Alexandra FedoseevaH-Index: 10
#2I. NikitinH-Index: 5
Last. Rustam KaibyshevH-Index: 58
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Abstract The nucleation of the Laves phase particles in a Re-containing 10% wt. Cr-3% Co-3% W steel with a low nitrogen and a high boron contents during creep is characterized by distinctive features. The precipitation process can be written as M23C6 carbide → M6C carbide → Laves phase. The nucleation of all phases in this precipitation sequence is heterogeneous. The M23C6 carbides precipitate on the boundaries of martensitic structure during tempering at temperature of 770 °C. The M6C (Fe3W3C) ...
5 CitationsSource
#1I. NikitinH-Index: 5
#2Alexandra FedoseevaH-Index: 10
Last. Rustam KaibyshevH-Index: 58
view all 3 authors...
The contributions from the martensitic laths, dislocations, secondary phase particles, and supersaturated solid solutions to the overall strength of the 12%Cr–3%Co–2.5%W creep-resistant steel with low N and high B contents were calculated after various heat treatments consisting of normalizing followed by medium-temperature tempering. An increase in the normalizing temperature from 1050 to 1150 °C led to an increase in the average size of the prior austenitic grains from 44 to 68 μm, but the δ-f...
6 CitationsSource
#1Alexandra FedoseevaH-Index: 10
#2I. NikitinH-Index: 5
Last. Rustam KaibyshevH-Index: 58
view all 4 authors...
Abstract Re-containing 10Cr-3Co-3W martensitic steel with low nitrogen and high boron contents exhibited a rupture time of 10,987 h at 650°C/140 MPa. This superior creep resistance was caused by partially saved tempered martensite lath structure due to precipitation of M23C6 carbides and Laves phase chains on lath boundaries as well as their high resistance to coarsening. M23C6 carbides were characterized by decreased interfacial energy that resulted in the retention of the orientation relations...
5 CitationsSource
Abstract A 9%Cr–3%Co steel with high B and low N contents exhibits creep strength breakdown at a temperature of 923 K after 3000 h. Specific feature of this steel is a distinct difference between short-term and long-term creep regimes for transient, steady state and tertiary creep stages. This behavior is unusual for high Cr steels and attributed to low density of M23C6 carbides precipitated on lath boundaries during tempering. Precipitation of Laves phase along these boundaries during transient...
7 CitationsSource
#1Nadezhda Dudova (Belgorod State University)H-Index: 13
#2R. Mishnev (Belgorod State University)H-Index: 10
Last. Rustam Kaibyshev (Belgorod State University)H-Index: 58
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Abstract The purpose of this study is to identify the relationships between the creep behavior of the 10% Cr martensitic steel with 0.008% B and 0.003% N and changes in microstructure and precipitations of secondary phases. Creep tests were carried out at 650 °C under an applied stress ranging from 180 to 120 MPa. The 10% Cr steel exhibits a linear stress vs. time to rupture dependence without creep strength breakdown up to approximately 40 000 h. The 100 000 h creep rupture strength at 650 °C i...
16 CitationsSource
#1Fujio Abe (National Institute for Materials Science)H-Index: 52
#2Toshio Ohba (National Institute for Materials Science)H-Index: 4
Last. Masaaki Tabuchi (National Institute for Materials Science)H-Index: 26
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ABSTRACTThe effect of tungsten–molybdenum (W–Mo) balance on creep life has been investigated for five heats of martensitic 9Cr steel with 1.5 % Mo equivalent (= 1/2W + Mo) at 600, 650 and 700°C. The combination of W and Mo concentrations in the present steel is 3W–0Mo, 2.8W–0.1Mo, 2.4W–0.3Mo, 1.8W–0.6Mo and 0W–1.5Mo. The time to rupture tr exhibits a monotonous increase with increasing the W–Mo balance parameter 1/2W/(1/2W + Mo), namely, with increasing W concentration and concomitantly with dec...
8 CitationsSource
#1Zhen Liu (USTB: University of Science and Technology Beijing)H-Index: 6
#2Zhengdong LiuH-Index: 2
Last. Zhengzong ChenH-Index: 3
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Abstract The microstructure and creep strength of three G115 specimens, 9 Cr-(2.3, 2.6, 3.0)W-3 Co (wt%), were investigated after creep test at 650 °C under 120 MPa using field emission transmission electron microscopy, field emission scanning electron microscopy, X-ray diffraction, and Ultra-high temperature confocal microscope, focusing on martensitic lath, precipitates, dislocation densities and the block boundaries. The results show that the coarsening rates of the laths and Laves phase part...
8 CitationsSource
#1Alexandra FedoseevaH-Index: 10
#2I. NikitinH-Index: 5
Last. Rustam KaibyshevH-Index: 58
view all 4 authors...
Abstract 9–12%Cr martensitic steels are perspective materials for critical components of new high-efficiency power plants working at ultra-supercritical parameters of steam. Addition of 0.2% rhenium in the experimental steel improved the short-term creep strength at 650 °C. Comparison of kinetics of tungsten depletion from the matrix in different high-Cr martensitic steels showed that rhenium in the experimental 10Cr-3Co-3W-0.2Re steel did not lead to retaining an increased amount of solute W in...
8 CitationsSource
#1E. Tkachev (Belgorod State University)H-Index: 6
#2Andrey Belyakov (Belgorod State University)H-Index: 41
Last. Rustam Kaibyshev (Belgorod State University)H-Index: 58
view all 3 authors...
Abstract The creep behavior of a 3%Co modified P92-type steel with high content of boron and low content of nitrogen was studied. The precipitation of Laves phase at lath boundaries provides a rapid decrease in the strain rate during transient creep. The finely dispersed (V,Nb)(C,N) carbonitrides uniformly distributed throughout and M23C6 carbides located at various boundaries/subboundaries result in extended steady-state creep. Gradual coarsening and an increase in the volume fraction of M23C6 ...
13 CitationsSource
#1J. P. Sanhueza (UdeC: University of Concepción)H-Index: 5
#2D. Rojas (UdeC: University of Concepción)H-Index: 11
Last. Sebastian Suarez (Saarland University)H-Index: 15
view all 6 authors...
A 12 pct Cr martensitic/ferritic steel was designed and produced to study Laves and Z-phase as precipitation hardening particles under creep conditions (650 °C). According to thermodynamic calculations, W and Cu additions were selected to ensure the precipitation of Laves after tempering. It is known that Z-phase formation does not follow the classical nucleation theory. Indeed, MX particles are transformed into Z-phase by Cr diffusion from the matrix to the precipitate. Therefore, to promote fa...
9 CitationsSource
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Abstract The coarsening of Laves phase in a Re-containing 10% Cr-3% Co-3% W steel during both creep and ageing at 923 K was investigated. The depletion of W solutes from the ferrite matrix is accompanied with the precipitation of Laves phase, wherein creep strain accelerates both these processes. The equilibrium W content in the ferritic matrix of 1.24 wt% and the volume fraction of Laves phase of 1.6% is reached after 500 h of creep and 1000 h of ageing. This is related to lower activation ener...
1 CitationsSource