Design and high temperature behavior of novel heat resistant steels strengthened by high density of stable nanoprecipitates

Vivas, Javier; De-Castro, David; Altstadt, E.; Houška, M.; San-Martín, David; Capdevila, Carlos

doi:10.1016/j.msea.2020.139799

Cited by 10 publications

(5 citation statements)

References 59 publications

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“…Currently, with the advances in the nuclear industry, there is an increasing need for the development or improvement of the structural materials used for critical structural elements -claddings of fuel elements of fast neutron reactors and in-core devices of the thermonuclear reactors [1][2][3][4].…”

Section: Introductionmentioning

confidence: 99%

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Fracture features of impact samples of low-activation ferritic-martensitic steel EK-181 after high-temperature thermomechanical treatment

et al. 2022

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A comparative fractographic investigation of fracture in the temperature range from −186 to 100°C of the Charpy impact samples is performed for the reactor low-activation ferritic-martensitic steel EK-181 after its high-temperature thermomechanical treatment (HTMT) and traditional heat treatment (THT). The mechanisms of steel fracture are revealed depending on the impact test temperature and treatment mode. On the upper and lower shelves of the impact toughness temperature curve, the steel fractures by the mechanism of transcrystalline ductile dimple fracture and transcrystalline quasicleavage, respectively. In the intermediate region (in ductile-brittle transition area), fracture occurs by a mixed mechanism. The transition temperature to the brittle state is determined, at which the proportion of ductile and brittle fractures is the same (after THT it is −3°C; after HTMT it is −14°C). It is established that HTMT significantly changes the type of fracture of the impact samples in comparison with THT. The microstructure formed during HTMT with hot deformation of austenite leads to the appearance of a crack-arrester type of delamination during the impact tests in the cold brittleness region, favoring an increase in the fracture toughness of the steel at a lower ductile-brittle transition temperature.

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Section: Introductionmentioning

confidence: 99%

“…These problems limit the lower and upper bounds of the operating temperatures range for such materials in the reactor core. The solution of these problems may be found in the development of optimal treatment modes or the selection of optimal compositions of ferriticmartensitic steels [2,4,11].…”

Section: Introductionmentioning

confidence: 99%

Fracture features of impact samples of low-activation ferritic-martensitic steel EK-181 after high-temperature thermomechanical treatment

et al. 2022

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“…[31,32] This indicates that the grain boundary strength has decreased to be lower than intragranular strength, [33,34] After the nucleation of voids, some voids grow and coalesce with the surrounding voids along boundaries to form large crack until the final rupture, which is consistent with what Vivas et al inferred. [10] In addition, the recovery of the matrix not only leads to grain softening to facilitate macroscopic deformations, but also accelerates the dynamic redistribution of alloying elements and speeds up the precipitation of alloy carbides, as shown in Figure 11a. However, for #3 steel, due to low degree of dynamic recovery, smaller sized lath-like shape grain has higher grain boundary strength and less stress concentration during the tensile test, thus decreasing the number of voids at boundaries.…”

Section: Correlation Between Grain Evolution and Fracture Behaviormentioning

confidence: 99%

“…[7,8] Zhang et al reported that the addition of 1.2% V could enhance the ultimate tensile strength (UTS) of MPS700V die steel from 400 to 550 MPa at 700 °C due to the increased nucleation of MC carbides. [9] According to Vivas et al, higher density of MX nanoprecipitates promoted by Co increases the high-temperature strength of 9Cr steels; [10] Jung et al reported that trace Mo and Mn additions favorably affected the high-temperature strength of austenitic cast steels. [11] Taneike et al demonstrated that replacing M 23 C 6 carbides with more stable precipitates, such as MX nanoscaled precipitates on lath and block boundaries, contributes to increasing high-temperature strength by a considerable degree due to the higher thermal stability of these latter precipitates.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

Gu,

Chi,

Zhou

et al. 2023

steel research int.

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In present work, nitrogen effects on microstructural evolution, fracture behavior of Cr‐Mo‐V hot‐working die steel during high‐temperature deformation at 700 °C are systematically investigated. The results reveal that increasing N/C ratio can enhance the amounts and stability of undissolved V(C, N) and enable austenitizing temperature of steel increase from 1030 °C to 1080‐1100 °C. Adding both nitrogen and nitrogen‐substituted carbon can increase the ultimate tensile strength (UTS) at 700 °C from 380 MPa to 480‐490 MPa, but had the inverse effect on resistance to crack initiation. Nitrogen addition promotes the M23C6 nucleation locating on the boundary and decrease resistance to crack initiation. The mechanisms of nitrogen‐substituted carbon contributing to the improvement of resistance to crack initiation and high‐temperature strength could be ascribed to several reasons. First, allowed higher austenitizing temperatures and lower carbides coarsening rates delayed matrix recovery and voids formation, ensuring grain boundary strength. Next, the amounts and coarsening rate of undesirable M23C6 located on the grain boundaries were effectively decreased, reducing the crack initiation. Then, increasing desirable V(C, N) could act as strong obstacles to the crack propagation. These results contributed to the further interpretation of nitrogen mechanisms in steels worked at high temperature.This article is protected by copyright. All rights reserved.

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“…The current working temperature of TC4 is lower than 500 C, which is much lower than some other alloys such as steel and nickel-based superalloys. [6,7] In addition, Ti alloys usually have poor electrical and thermal conductivity (around 10 W/ (m K)), [8] which greatly limits their applications. [9][10][11] Introducing reinforcements with high strength and high thermal conductivity in Ti alloys to make a Ti matrix composite (TMC) is an effective method to improve its overall properties.…”

mentioning

confidence: 99%

Room‐/High‐Temperature Mechanical Properties of Titanium Matrix Composites Reinforced with Discontinuous Carbon Fibers

et al. 2021

Adv Eng Mater

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Titanium (Ti) and its alloys possessing high specific strength, specific stiffness, good heat and corrosion resistance, and a relatively low density are widely used as structural materials in aviation, aerospace, automotive, biomedical, and many other industry fields. [1][2][3] TiÀ6AlÀ4V (TC4) is the most representative Ti alloy because of its overall excellent room-temperature properties. [4,5] However, the high-temperature mechanical properties of the TC4 alloy are relatively poor. The current working temperature of TC4 is lower than 500 C, which is much lower than some other alloys such as steel and nickel-based superalloys. [6,7] In addition, Ti alloys usually have poor electrical and thermal conductivity (around 10 W/ (m K)), [8] which greatly limits their applications. [9][10][11] Introducing reinforcements with high strength and high thermal conductivity in Ti alloys to make a Ti matrix composite (TMC) is an effective method to improve its overall properties. [12][13][14] Carbon fiber (CFs) is a fiber material with excellent physical, mechanical, and thermal properties. Its diameter is on the level of several micrometers, while the length can reach up to centimeters. This characteristic makes them not only possess high aspect ratios but also be easier to disperse homogeneously in metal matrices compared with nanocarbon reinforcements. [15][16][17] The density of CFs is only %1.80 g cm À3 (40% of Ti) but the axial tensile strength of CFs is above 3.5 GPa (>300% of Ti). CFs' high-temperature resistance ranks among the top in all chemical fibers, [18] which are shown to be ultrahigh temperature (over 2000 C) resistant in the nonoxidizing environment. Last but not least, the thermal conductivity of CFs is around 5000 W/(m K) (%500 times of Ti). Therefore, CF is a promising reinforcement to prepare high-performance TMCs, which can be expected to make up the aforementioned shortcomings of Ti alloys.Currently, continuous long CFs are often applied to fabricate high-strength TMCs. [19][20][21][22][23] Even et al. [24] adhered long CFs on the surface of titanium alloy powder by viscous organic polymers and then used hot isostatic pressing (HIP) to produce continuous CFs-reinforced TMCs under the conditions of 600À700 C, 200 MPa, and 1 h. The composites were all above 98% in density and the ultimate tensile strength (UTS) reached 600 MPa at room temperature. Yang et al. [25] used copper-coated continuous CF cloth as reinforcement and TC4 as matrix. After they were compressed and stacked on top of each other, CF cloth/TC4 composites were manufactured by spark plasma sintering (SPS). The compressive yield strength (YS) increased by 370 MPa compared with TC4 matrix at a strain rate of 4200 s À1 because of the tight interface bonding. Overall, the fabrication process of the aforementioned continuous CFs-reinforced TMCs is complicate. In addition, they can only achieve good performance in certain specific directions, showing anisotropic characteristics.

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Design and high temperature behavior of novel heat resistant steels strengthened by high density of stable nanoprecipitates

Cited by 10 publications

References 59 publications

Fracture features of impact samples of low-activation ferritic-martensitic steel EK-181 after high-temperature thermomechanical treatment

Fracture features of impact samples of low-activation ferritic-martensitic steel EK-181 after high-temperature thermomechanical treatment

Nitrogen Effects on Microstructural Evolution, Fracture Behavior of Cr–Mo–V Hot‐Working Die Steel during High‐Temperature Deformation at 700 °C

Room‐/High‐Temperature Mechanical Properties of Titanium Matrix Composites Reinforced with Discontinuous Carbon Fibers

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