Nucleation of W-rich carbides and Laves phase in a Re-containing 10% Cr steel during creep at 650 °C

Published on Nov 1, 2020in Materials Characterization3.562
· DOI :10.1016/J.MATCHAR.2020.110651
Alexandra Fedoseeva10
Estimated H-index: 10
,
I. Nikitin5
Estimated H-index: 5
+ 1 AuthorsRustam Kaibyshev58
Estimated H-index: 58
Source
Abstract
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) carbides precipitate during both tempering at 770 °C and creep at 650 °C on the M23C6/ferrite surfaces and on the martensitic lath boundaries. The M6C carbides have the mutual relationship of crystal orientations with both the M23C6 carbides and ferrite. The chemical composition of the M6C carbides depends on their nucleation sites. After 83 h of creep, the M6C carbides starts to dissolve, whereas the Laves phase particles are nucleated on the M6C/ferrite surface and separately on the martensitic lath boundaries. The Laves phase particles nucleate on the M6C/ferrite surface are smaller than those nucleated on the martensitic lath boundaries. The Laves phase particles exhibit the unique orientation relationships with a high misfit. The transformation of M23C6 → M6C → Laves phase is an in-situ transformation accompanied by chemical compositional changes.
📖 Papers frequently viewed together
54 Citations
32 Citations
5 Authors (O. Prat, ..., Gerhard Inden)
69 Citations
References56
Newest
#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
view all 3 authors...
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
view all 5 authors...
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
view all 4 authors...
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
#1Kevin Gordon Abstoss (Chemnitz University of Technology)H-Index: 3
#2S. SchmigallaH-Index: 1
Last. Peter Mayr (Chemnitz University of Technology)H-Index: 18
view all 4 authors...
Abstract The high creep strength of advanced boron alloyed 9 wt% Cr steels results from a precipitate stabilised martensitic microstructure. Grain boundaries and sub-boundaries are effectively pinned by boron stabilised precipitates. However, during creep exposure several degradation mechanisms with regards to precipitates are active such as, particle coarsening, phase transformations, dissolution of precipitates and precipitation of new phases. This diffusion driven phenomena affect the type, s...
7 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
#1P. Prakash (NITW: National Institute of Technology, Warangal)H-Index: 3
#2J. Vanaja (RRC: Indira Gandhi Centre for Atomic Research)H-Index: 10
Last. Kinkar LahaH-Index: 9
view all 6 authors...
Abstract Effect of thermo-mechanical processing on tensile behaviour of reduced activation ferritic martensitic (RAFM) steel has been assessed and compared with those of the normalized and tempered steel. The thermo-mechanical treatment (TMT) was carried out by performing hot rolling and ageing in the austenite phase field, air cooled followed by tempering. TMT of the steel increased its hardness compared to the normalized and tempered condition. Tensile strength of the steel increased on TMT ov...
12 CitationsSource
Cited By5
Newest
Source
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
Abstract Nano-scale precipitation is critical for martensitic steels to achieve ultra-high strengths. To date, there is a lack of in-depth understanding about tailoring Co addition to optimize strengthening precipitations in Fe-Cr-Co-Mo-Ni-C steels. This research reveals that a high addition of Co in a Fe-Cr-Co-Mo-Ni-C steel significantly promotes multiple precipitation of Mo-rich intermetallic compounds (IMCs), carbides and α’-Cr, and achieve an exceptional hardening effect during aging at 540 ...
Source
view all 6 authors...
Source
#1Alexandra FedoseevaH-Index: 10
#2Ivan NikitinH-Index: 2
Last. Rustam KaibyshevH-Index: 58
view all 6 authors...
3 CitationsSource