The сrack growth characteristics are investigated in situ in a scanning electron microscope column during the tension of the welded joints of two-phase (γ + δ) and single-phase (γ) 05Kh22AG16N8M ...steel containing 0.36 and 0.52 wt % N, respectively. A crack in the steel with 0.36% N and its welded joint is shown to form and develop at a low load and strain due to the existence of the σ phase in the steel structure and δ ferrite in the welded joint.
This article focuses on modeling 90Sr migration in strong nitrate solutions in aquifers used for radioactive waste disposal. This type of radioactive waste disposal is typical only for the Russian ...Federation and is a unique object of study. The calculations are based on the laboratory study of strontium sorption in nitrate solutions on sandy, loamy and clayey rocks under biotic (with natural microbial communities obtained from Seversky repository) and abiotic conditions. To obtain a strontium sorption model, first, an ion exchange model in PHREEQC software is fitted to the experimental data both manually and automatically (using MOUSE software). Since real nitrate-ion concentrations at radioactive waste injection sites can reach values of hundreds of grams per liter, strontium Kd values are predicted for high ionic strength (for which no experimental study of strontium sorption efficiency has been carried out) with PHREEQC-model. The strontium transport models accounting for sorption and the nitrate reduction processes have been developed using two numerical software packages: the GeRa 3D hydrogeological simulation code and the PHREEQC reactive transport code. Reactive transport modeling under different conditions shows a high sensitivity to dispersion. A significant effect of sorption of nitrate ion on Sr sorption is shown and a relatively small contribution of microbial processes to strontium transport is noted for liquid radioactive waste injection sites.
Display omitted
•Model of ion exchange and NO3− reduction was used for Sr reactive transport modeling.•Microbial nitrate reduction can affect Sr transport in subsurface media.•Nitrate-ion cannot be considered as a neutral non-absorbable tracer.
The crack growth characteristics are investigated in situ in a scanning electron microscope column during the tension of nonmagnetic 04Kh18AG20 steel specimens with a overequilibrium nitrogen content ...(0.98 wt % N) and various vanadium contents. The character of crack nucleation and propagation in steel after quenching from 1200°С and after subsequent aging at 650°С for 5 h is shown to be the same. The critical shear crack size at the maximum load is 300 μm in vanadium-free 04Kh18AG20 steel and 120 μm in vanadium-bearing 04Kh18AG20F steel. Corrosion-resistant nickel and vanadium-free austenitic 04Kh18AG20 steel (0.98 wt % N) after quenching from 1200°C is recommended for heavy-duty nonmagnetic structures.
The results of the structure and stacking fault energy (SFE) investigations of low-carbon austenitic steels alloyed with substitutional elements are summarized. An increase in the manganese content ...in the range 7–20 wt % in Fe–Mn alloys is shown to make austenite stable to the γ–α transformation and unstable to the γ–ε transformation. Ferromanganese steel containing 20 wt % Mn has the maximum number (50–55%) of stacking faults after deformation. The SFE of Fe–Mn alloys is inversely proportional to the manganese content at Mn < 14 wt % and directly proportional at higher manganese concentrations. A temperature dependence of the SFE on the manganese content is found for Fe–Mn alloys. The effect of chromium on the SFE depends on the manganese content. A linear dependence of the SFE on the nickel content in Cr–Ni steels with 10–25 wt % Cr is found in the concentration range 10–25 wt %.
The structure and mechanical properties of martensitic–ferritic nitrogen-bearing 08Kh17N2AF steel after quenching in the temperature range 800–1200°C are studied. This steel after quenching from ...950°C is found to have a high strength (σ
u
= 1290 MPa, σ
0.2
= 850 MPa) and impact toughness at +20°C (
KCU
= 0.8 MJ/m
2
) but a low impact toughness at –70°C (
KCU
= 0.3 MJ/m
2
) as a result of the formation of a martensitic–ferritic–austenitic structure containing ∼82% α, ∼17% δ, ∼1% γ, and a small amount of chromium carbonitrides. The 08Kh17N2AF steel is noted to have the best combination of strength (σ
u
= 950 MPa, σ
0.2
= 800 MPa) and impact toughness at +20 and –70°C (
KCU
+20°C
= 1.65 MJ/m
2
,
KCU
–70°C
= 0.7 MJ/m
2
) after quenching from 800°C and cooling in water as a result of the formation of a martensitic–ferritic–austenitic structure containing 75% martensitic with a high dislocation density, 17% ferrite with grain sizes 2–3 μm, and 8% austenite. The increased impact toughness at +20°C and –70°C is shown to be related to a low content of chromium and vanadium carbonitrides and thin-lamellar martensite having formed from fine austenite grains.
—The structure and mechanical properties of rods of low-alloy martensitic steels with an overequilibrium nitrogen content, which are melted in a vacuum induction furnace with subsequent electroslag ...remelting under nitrogen pressure and are manufactured by free forging, are studied. The distribution of alloying elements and the hardness along the rod length is found to be uniform. The α → γ transformation temperature on hearting,
Ac
1
= 662°C and
Ac
3
= 838°C, of the steels are determined by differential scanning calorimetry. The structure of these steels contains a small amount of disperse particles of manganese sulfides and vanadium nitrides. Quenching and low tempering of the steels are shown to lead to a good combination of a high strength (σ
u
= 2150–2170 MPa, σ
0.2
= 1450–1480 MPa), ductility (δ = 12–14%, ψ = 35–40%), and impact toughness (KCU = 0.6–0.7 MJ/m
2
) as a result of formation of a fine-grained structure consisting of 85–87% lath martensite and 13–15% retained austenite, thin layers of which are placed between martensite laths.
The works on the structure and mechanical properties of aluminum-alloyed austenitic steels are analyzed. Aluminum in aging high-nitrogen Cr–Mn–Ni–V nonmagnetic steels is shown to decrease the ...strength due to a decrease in the amount of dispersed VN nitrides having precipitated during aging because of the formation of coarse AlN particles hard to dissolve on quenching heating. An additional increase in the strength of aging nonmagnetic Mn–Ni–V–C steels is reached by their alloying with aluminum, which does not form hard to dissolve compounds with carbon. A significant increase in the surface hardness and the wear resistance during nitriding is reached as a result of separate or complex alloying of Mn–Ni–V steels with chromium up to 3% and aluminum up to 1.2%, which increase the nitrided layer thickness. The best combination of the properties of the nitrided layer is achieved after nitriding these steels containing 2.5–3.5% V at 700°C (12 h) in a 80% N
2
+ 20% HN
3
medium. In this case, the hardening of the core during aging is related to the precipitation of VC carbides, and that of the nitrided layer, to the formation of VN nitrides. A significant increase in the volume fraction of strengthening phases in manganese steels is reached by complex alloying with Al, Ni, Cu, and V in the amounts that provide the simultaneous precipitation of the VC carbide and NiAl intermetallics during aging. Nonmagnetic 50G17N10Yu4F2 steel with a combined carbide–intermetallic hardening is highly competitive in strength (σ
u
> 1600 MPa, σ
0.2
> 1400 MPa) with high-strength 18Kh2N4VA ferromagnetic steels and significantly surpasses the well-known aging nonmagnetic high-nitrogen alloys.
Stability of the structure and mechanical properties of high-strength cryogenic nonmagnetic steels 10Kh19G10N6AM2 and 09Kh19G10N6AM2D2 under long-term thermocycling and multicycle mechanical loading ...is investigated. The mechanical properties of the steels are determined by measuring the
HV
hardness and testing for tensile strength and impact bending. The phase compositions and the structures of the steels are studied by dilatometry, magnetometry and x-ray diffractometry after various impacts (thermocycling, fatigue loading, and final testing for determination of mechanical properties).
Experiments at the Super Charm-Tau factory Achasov, Mikhail N.; Blinov, Vladimir E.; Bobrov, Alexander V. ...
Physics Uspekhi,
01/2024, Letnik:
67, Številka:
1
Journal Article
The synthesis and
in silico
prediction of the molecular-targeted anti-EGFR inhibitory activity of a novel dihydroacridinone derivative are reported. 9-Aminium-3,3-dimethyl-3,4-dihydroacridin-1(2
H
...)-one
L
-2-hydroxybutanedioate (LHT-17-19) was obtained 99.8% pure by mixing and heating equimolar amounts of 9-amino-3,3-dimethyl-3,4-dihydroacridin-1(2
H
)-one and
L
-2-hydroxybutanedioic acid in 50% EtOH. Virtual molecular screening of the spectrum of effects of the compound revealed inhibitory properties against several intracellular targets, i.e., carcinogenesis drivers, among which the EGFR kinase domain had the highest probability. Docking of LHT-17-19 base to the EGFR kinase domain formed a molecular complex with a high affinity and bonding energy. The results suggested that LHT-17-19 had high antitumor activity against malignant neoplasms expressing EGFR.
